**Tegillarca nodifera (Martens, 1860)**

Figs 12A, 14A

*Arca nodifera* Martens, 1860: 17. Type locality: Bankok [Bangkok, Thailand].

*Anadara nodifera*. Nateewathana et al. 1981: 63. Nateewathana 1995: 101, with in-text fig. Poutiers 1998a: 148, with in-text figs. Aungtonya et al. 1999: 372. Hylleberg and Kilburn 2003: 148–149, pl. 1, fig. 5. Nabhitabhata 2009: 284. Hylleberg and Aungtonya 2013: 94.

*Anadara* (*Tegillarca*) *nodifera*. Vongpanich 1996: 189–190, figs 51–54.

*Tegillarca nodifera*. Swennen et al. 2001: 44, 67, text-fig. 26, fig. 36. Thach 2005: 244, pl. 75, fig. 18. Huber 2010: 141, with in-text fig. Huber 2015: C3366. BEDO 2017a: 28, with in-text fig. Yang et al. 2017: 150, fig. 587. Tudu et al. 2018: table 1. Tudu et al. 2019: 44, fig. 5e, f. Wells et al. 2021: 54.

**Referred material.** CUF-NKNY-B01, B02, B15 (26L+31R shells; Figs 12A, 14A).

**Habitat.** On mud and sand bottoms, in intertidal or near mangrove forests and shallow sublittoral waters down to a depth of 10 m (Poutiers 1998a; Huber 2015).

**Distribution.** Eastern Indian Ocean; Indo-West Pacific, from East China Sea to Indonesia (Poutiers 1998a; Huber 2015; Tudu et al. 2019).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species, *Tegillarca granosa*, by having a more elongated shell with a higher number of ribs (19–23) and a higher number of nodules on ribs (Tudu et al. 2019).

**Family Noetiidae Stewart, 1930**

*Estellacar* Iredale, 1939

**Estellacar olivacea (Reeve, 1844)**

Figs 12F, 14B

*Arca olivacea* Reeve, 1844: *Arca*, pl. 16, sp. 113. Type locality: San Nicolas, island of Zebu [the Philippines] (found in sandy mud at the depth of four fathoms).

*Estellacar olivacea*. Poutiers 1998a: 160, with in-text figs. Swennen et al. 2001: 44, 68, fig. 42. Robba et al. 2002: 61, pl. 2, fig. 13. Hylleberg and Kilburn 2003: 153. Robba et al. 2003: table 2. Vongpanich and Matsukuma 2004: 41, pl. 2, figs. r, s. Robba et al. 2007: 84 (appendix). Nabhitabhata 2009: 297. Huber 2010: 146, with in-text fig. Negri et al. 2014: table 3. Huber 2015: C3594. BEDO 2017a: 42, with in-text fig. Wells et al. 2021: 55.

*Striarca olivacea*. Printrakoon et al. 2008: table 1.

**Referred material.** CUF-NKNY-B18 (16L+14R shells; Figs 12F, 14B).

**Habitat.** In mud and sand from intertidal zones, often near mangrove forests, down to 20 m depth (Poutiers 1998a; Robba et al. 2002).

**Distribution.** India; Indo-West Pacific, from South China to the Philippines (Huber 2015). Records of fossils from the Holocene in Thailand (Robba et al. 2002).
**Tegillarca nodifera (Martens, 1860)**

Figs 12A, 14A

*Arca nodifera* Martens, 1860: 17. Type locality: Bankok [Bangkok, Thailand].

*Anadara nodifera*. Nateewathana et al. 1981: 63. Nateewathana 1995: 101, with in-text fig. Poutiers 1998a: 148, with in-text figs. Aungtonya et al. 1999: 372. Hylleberg and Kilburn 2003: 148–149, pl. 1, fig. 5. Nabhitabhata 2009: 284. Hylleberg and Aungtonya 2013: 94.

*Anadara* (*Tegillarca*) *nodifera*. Vongpanich 1996: 189–190, figs 51–54.

*Tegillarca nodifera*. Swennen et al. 2001: 44, 67, text-fig. 26, fig. 36. Thach 2005: 244, pl. 75, fig. 18. Huber 2010: 141, with in-text fig. Huber 2015: C3366. BEDO 2017a: 28, with in-text fig. Yang et al. 2017: 150, fig. 587. Tudu et al. 2018: table 1. Tudu et al. 2019: 44, fig. 5e, f. Wells et al. 2021: 54.

**Referred material.** CUF-NKNY-B01, B02, B15 (26L+31R shells; Figs 12A, 14A).

**Habitat.** On mud and sand bottoms, in intertidal or near mangrove forests and shallow sublittoral waters down to a depth of 10 m (Poutiers 1998a; Huber 2015).

**Distribution.** Eastern Indian Ocean; Indo-West Pacific, from East China Sea to Indonesia (Poutiers 1998a; Huber 2015; Tudu et al. 2019).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species, *Tegillarca granosa*, by having a more elongated shell with a higher number of ribs (19–23) and a higher number of nodules on ribs (Tudu et al. 2019).

**Family Noetiidae Stewart, 1930**

*Estellacar* Iredale, 1939

**Estellacar olivacea (Reeve, 1844)**

Figs 12F, 14B

*Arca olivacea* Reeve, 1844: *Arca*, pl. 16, sp. 113. Type locality: San Nicolas, island of Zebu [the Philippines] (found in sandy mud at the depth of four fathoms).

*Estellacar olivacea*. Poutiers 1998a: 160, with in-text figs. Swennen et al. 2001: 44, 68, fig. 42. Robba et al. 2002: 61, pl. 2, fig. 13. Hylleberg and Kilburn 2003: 153. Robba et al. 2003: table 2. Vongpanich and Matsukuma 2004: 41, pl. 2, figs. r, s. Robba et al. 2007: 84 (appendix). Nabhitabhata 2009: 297. Huber 2010: 146, with in-text fig. Negri et al. 2014: table 3. Huber 2015: C3594. BEDO 2017a: 42, with in-text fig. Wells et al. 2021: 55.

*Striarca olivacea*. Printrakoon et al. 2008: table 1.

**Referred material.** CUF-NKNY-B18 (16L+14R shells; Figs 12F, 14B).

**Habitat.** In mud and sand from intertidal zones, often near mangrove forests, down to 20 m depth (Poutiers 1998a; Robba et al. 2002).

**Distribution.** India; Indo-West Pacific, from South China to the Philippines (Huber 2015). Records of fossils from the Holocene in Thailand (Robba et al. 2002).
**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species *Estellacar galactodes* (Benson, 1842) by having a higher number of coarser riblets (Robba et al. 2002).

**Noetiella Thiele, 1931**

**Noetiella pectunculiformis (Dunker, 1866)**

Figs 12D, 14C

*Barbatia pectunculiformis* Dunker, 1866: 88–89, pl. 28, figs 4–6. Type locality: Borneo.

*Arca* (*Fossularca*) *pectunculiformis*. Lynge 1909: 115.

*Striarca pectunculiformis*. Tantanasiriwong 1979: 4. Morris and Purchon 1981: 323. Nateewathana et al. 1981: 63. Aungtonya et al. 1999: 373.

*Scelidionarca pectunculiformis*. Robba et al. 2002: 61, pl. 2, fig. 14q, b. Robba et al. 2007: 84 (appendix). Nabhitabhata 2009: 297.

*Noetiella pectunculiformis*. Huber 2010: 146, with in-text fig. Huber 2015: C3575. BEDO 2017a: 43, with in-text fig. Kantharajan et al. 2017: table 1, fig. 2-11. Wells et al. 2021: 55.

**Referred material.** CUF-NKNY-B27 (4L+4R shells; Figs 12D, 14C).

**Habitat.** In soft clay, mud or sand, in subtidal zones from a depth of 2–43 m, and in mangrove forests (Huber 2015; Kantharajan et al. 2017).

**Distribution.** India Ocean; Indo-West Pacific, from South China to Indonesia (Huber 2015; Kantharajan et al. 2017). Records of fossils from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Robba et al. (2002) and Huber (2010), specifically in having a roundly trapezoidal and inequilateral shell shape with the sculpture of dense, faint radials, and coarse growth markings.

**Order Ostreida Férussac, 1822**

**Superfamily Ostreoidea Rafinesque, 1815**

**Family Ostreidae Rafinesque, 1815**

**Magallana Salvi & Mariottini, 2016**

**Magallana cf. gigas (Thunberg, 1793)**

Figs 12E, 14D

cf. *Ostrea gigas* Thunberg, 1793: 140–142, pl. 6, figs 1–3. Type locality: Japan. Yokoyama 1927: 402.

cf. *Crassostrea gigas*. Tantanasiriwong 1979: 7. Nateewathana et al. 1981: 65. Poutiers 1998a: 233, with in-text figs. Aungtonya et al. 1999: 375. Robba et al. 2002: 69, 71, pl. 5, fig. 3a, b. Hylleberg and Kilburn 2003: 162. Beu et al. 2004: 154–156, fig. 9d. Thach 2005: 257. Robba et al. 2007: 84 (appendix). Printrakoon et al. 2008: table 1. Huber 2010: 180, with in-text fig. Sanpanich 2011: table 2. Huber 2015: C5155. Okutani 2017: 1183, pl. 483, fig. 7. Yang
**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species *Estellacar galactodes* (Benson, 1842) by having a higher number of coarser riblets (Robba et al. 2002).

**Noetiella Thiele, 1931**

**Noetiella pectunculiformis (Dunker, 1866)**

Figs 12D, 14C

*Barbatia pectunculiformis* Dunker, 1866: 88–89, pl. 28, figs 4–6. Type locality: Borneo.

*Arca* (*Fossularca*) *pectunculiformis*. Lynge 1909: 115.

*Striarca pectunculiformis*. Tantanasiriwong 1979: 4. Morris and Purchon 1981: 323. Nateewathana et al. 1981: 63. Aungtonya et al. 1999: 373.

*Scelidionarca pectunculiformis*. Robba et al. 2002: 61, pl. 2, fig. 14q, b. Robba et al. 2007: 84 (appendix). Nabhitabhata 2009: 297.

*Noetiella pectunculiformis*. Huber 2010: 146, with in-text fig. Huber 2015: C3575. BEDO 2017a: 43, with in-text fig. Kantharajan et al. 2017: table 1, fig. 2-11. Wells et al. 2021: 55.

**Referred material.** CUF-NKNY-B27 (4L+4R shells; Figs 12D, 14C).

**Habitat.** In soft clay, mud or sand, in subtidal zones from a depth of 2–43 m, and in mangrove forests (Huber 2015; Kantharajan et al. 2017).

**Distribution.** India Ocean; Indo-West Pacific, from South China to Indonesia (Huber 2015; Kantharajan et al. 2017). Records of fossils from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Robba et al. (2002) and Huber (2010), specifically in having a roundly trapezoidal and inequilateral shell shape with the sculpture of dense, faint radials, and coarse growth markings.

**Order Ostreida Férussac, 1822**

**Superfamily Ostreoidea Rafinesque, 1815**

**Family Ostreidae Rafinesque, 1815**

**Magallana Salvi & Mariottini, 2016**

**Magallana cf. gigas** (Thunberg, 1793)

Figs 12E, 14D

cf. *Ostrea gigas* Thunberg, 1793: 140–142, pl. 6, figs 1–3. Type locality: Japan. Yokoyama 1927: 402.

cf. *Crassostrea gigas*. Tantanasiriwong 1979: 7. Nateewathana et al. 1981: 65. Poutiers 1998a: 233, with in-text figs. Aungtonya et al. 1999: 375. Robba et al. 2002: 69, 71, pl. 5, fig. 3a, b. Hylleberg and Kilburn 2003: 162. Beu et al. 2004: 154–156, fig. 9d. Thach 2005: 257. Robba et al. 2007: 84 (appendix). Printrakoon et al. 2008: table 1. Huber 2010: 180, with in-text fig. Sanpanich 2011: table 2. Huber 2015: C5155. Okutani 2017: 1183, pl. 483, fig. 7. Yang
et al. 2017: 176, 178, fig. 685. Surakiatchai et al. 2018: table 6, pl. 3, fig. 6a, b. Tudu et al. 2018: table 1.

cf. *Crassostrea* cf. *gigas*. Swennen et al. 2001: 45, 72, text-fig. 62, fig. 62.

cf. *Crassostrea* (*Magallana*) *gigas*. Lutaenko et al. 2019: 187–188, pl. 15, fig. a–f.

cf. *Magallana gigas*. Wells et al. 2021: 60.

**Referred material.** CUF-NKNY-B13 (130L+16R shells; Figs 12E, 14D).

**Habitat.** Attached to rocks from intertidal zones down to 30 m depth, in mud, bays, and sheltered areas that are often brackish with low salinity water (Thach 2005; Huber 2015).

**Distribution.** Cosmopolitan (Huber 2015). Records of fossils from the Miocene to Holocene in Japan, New Zealand, Taiwan, and Thailand (Robba et al. 2002; Beu et al. 2004; Surakiatchai et al. 2018).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** The cupped oysters in the subfamily Crassostreinae could not be identified at species level based on shell characters or soft tissue alone (Salvi and Mariottini 2021). Therefore, we tentatively identify these specimens of giant cupped oysters as belonging to *Magallana gigas*, due to large and thick shells and the presence of this species in Thailand (Wells et al. 2021).

**Order Pectinida Gray, 1854**

**Superfamily Anomioidea Rafinesque, 1815**

**Family Placunidae Rafinesque, 1815**

**Placuna Lightfoot, 1786**

**Placuna placenta (Linnaeus, 1758)**

Figs 13A, 14E

*Anomia placenta* Linnaeus, 1758: 703. Type locality: unknown.

*Placuna placenta*. Lynge 1909: 107–108. Tantanasiriwong 1979: 6. Morris and Purchon 1981: 324. Nateewathana et al. 1981: 64. Oliver 1992: 86, pl. 17, fig. 6a, b. Bosch et al. 1995: 234, fig. 1018. Poutiers 1998a: 218, with in-text figs. Aungtonya et al. 1999: 376. Subba Rao and Dey 2000: 230. Swennen et al. 2001: 46, 76, text-fig. 80, fig. 80. Robba et al. 2002: 77, pl. 6, fig. 10a, b. Hylleberg and Kilburn 2003: 169–170. Robba et al. 2003: table 5. Dharma 2005: 246, pl. 98, fig. 17. Dey and Ramakrishna 2007: 154, 197. Robba et al. 2007: 84 (appendix). Nabhitabhata 2009: 20, with in-text fig., 347. Huber 2010: 190, with in-text fig. Sanpanich 2011: table 2. Huber 2015: C5627. Yang et al. 2017: 176, fig. 681. Surakiatchai et al. 2018: table 6, pl. 3, fig. 8a, b. Tudu et al. 2018: table 1. Wells et al. 2021: 64.

*Placuna* (*Placuna*) *placenta*. Dheeradilok et al. 1984: pl. 2, fig. 14. Thach 2005: 266, pl. 81, fig. 4.

**Referred material.** CUF-NKNY-B22 (19L+18R shells; Figs 13A, 14E).

**Habitat.** Sandy mud in intertidal zones and shallow waters down to 35 m depth, in quiet waters of lagoons, protected bays, and mangrove areas, or near estuaries (Poutiers 1998a; Thach 2005; Yang et al. 2017).
et al. 2017: 176, 178, fig. 685. Surakiatchai et al. 2018: table 6, pl. 3, fig. 6a, b. Tudu et al. 2018: table 1.

cf. *Crassostrea* cf. *gigas*. Swennen et al. 2001: 45, 72, text-fig. 62, fig. 62.

cf. *Crassostrea* (*Magallana*) *gigas*. Lutaenko et al. 2019: 187–188, pl. 15, fig. a–f.

cf. *Magallana gigas*. Wells et al. 2021: 60.

**Referred material.** CUF-NKNY-B13 (130L+16R shells; Figs 12E, 14D).

**Habitat.** Attached to rocks from intertidal zones down to 30 m depth, in mud, bays, and sheltered areas that are often brackish with low salinity water (Thach 2005; Huber 2015).

**Distribution.** Cosmopolitan (Huber 2015). Records of fossils from the Miocene to Holocene in Japan, New Zealand, Taiwan, and Thailand (Robba et al. 2002; Beu et al. 2004; Surakiatchai et al. 2018).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** The cupped oysters in the subfamily Crassostreinae could not be identified at species level based on shell characters or soft tissue alone (Salvi and Mariottini 2021). Therefore, we tentatively identify these specimens of giant cupped oysters as belonging to *Magallana gigas*, due to large and thick shells and the presence of this species in Thailand (Wells et al. 2021).

**Order Pectinida Gray, 1854**

**Superfamily Anomioidea Rafinesque, 1815**

**Family Placunidae Rafinesque, 1815**

**Placuna Lightfoot, 1786**

**Placuna placenta (Linnaeus, 1758)**

Figs 13A, 14E

*Anomia placenta* Linnaeus, 1758: 703. Type locality: unknown.

*Placuna placenta*. Lynge 1909: 107–108. Tantanasiriwong 1979: 6. Morris and Purchon 1981: 324. Nateewathana et al. 1981: 64. Oliver 1992: 86, pl. 17, fig. 6a, b. Bosch et al. 1995: 234, fig. 1018. Poutiers 1998a: 218, with in-text figs. Aungtonya et al. 1999: 376. Subba Rao and Dey 2000: 230. Swennen et al. 2001: 46, 76, text-fig. 80, fig. 80. Robba et al. 2002: 77, pl. 6, fig. 10a, b. Hylleberg and Kilburn 2003: 169–170. Robba et al. 2003: table 5. Dharma 2005: 246, pl. 98, fig. 17. Dey and Ramakrishna 2007: 154, 197. Robba et al. 2007: 84 (appendix). Nabhitabhata 2009: 20, with in-text fig., 347. Huber 2010: 190, with in-text fig. Sanpanich 2011: table 2. Huber 2015: C5627. Yang et al. 2017: 176, fig. 681. Surakiatchai et al. 2018: table 6, pl. 3, fig. 8a, b. Tudu et al. 2018: table 1. Wells et al. 2021: 64.

*Placuna* (*Placuna*) *placenta*. Dheeradilok et al. 1984: pl. 2, fig. 14. Thach 2005: 266, pl. 81, fig. 4.

**Referred material.** CUF-NKNY-B22 (19L+18R shells; Figs 13A, 14E).

**Habitat.** Sandy mud in intertidal zones and shallow waters down to 35 m depth, in quiet waters of lagoons, protected bays, and mangrove areas, or near estuaries (Poutiers 1998a; Thach 2005; Yang et al. 2017).
<figure><img src="image_14.png" /><figcaption>**Figure 14.** Bivalves A *Tegillarca nodifera* B *Estellacar olivacea* C *Noetiella pectunculiformis* D *Magallana cf. gigas* E *Placuna placenta* F *Volachlamys singaporina*.</figcaption></figure>

**Distribution.** Indian Ocean; Indo-West Pacific, from Japan to Australia (Hu-ber 2015). Records of fossils from the Late Miocene to Holocene in Indonesia, Japan, the Philippines, Taiwan, and Thailand (Robba et al. 2002; Surakiatchai et al. 2018).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species, *Placuna ephippium* (Philipsson, 1788), by having an almost circular shell and a right valve bearing a hinge plate with arrowhead-shaped lamellar teeth with the posterior ridge distinctly longer than the anterior one (Poutiers 1998a; Swennen et al. 2001).
<figure><img src="image_15.png" /><figcaption>**Figure 14.** Bivalves A *Tegillarca nodifera* B *Estellacar olivacea* C *Noetiella pectunculiformis* D *Magallana cf. gigas* E *Placuna placenta* F *Volachlamys singaporina*.</figcaption></figure>

**Distribution.** Indian Ocean; Indo-West Pacific, from Japan to Australia (Hu-ber 2015). Records of fossils from the Late Miocene to Holocene in Indonesia, Japan, the Philippines, Taiwan, and Thailand (Robba et al. 2002; Surakiatchai et al. 2018).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species, *Placuna ephippium* (Philipsson, 1788), by having an almost circular shell and a right valve bearing a hinge plate with arrowhead-shaped lamellar teeth with the posterior ridge distinctly longer than the anterior one (Poutiers 1998a; Swennen et al. 2001).
**Superfamily Pectinoidea Rafinesque, 1815**

**Family Pectinidae Rafinesque, 1815**

**Volachlamys Iredale, 1939**

**Volachlamys singaporina (Sowerby II, 1842)**

Figs 12B, 14F

*Pecten singaporinus* Sowerby II, 1842: 74, pl. 13, fig. 55; pl. 14, fig. 71. Type locality: Singapore. Lynge 1909: 155.

*Volachlamys singaporina*. Roussy 1991: 21. Poutiers 1998a: 210, with in-text figs. Aungtonya et al. 1999: 376. Swennen et al. 2001: 45, 74, fig. 70. Gemert 2003: 108. Hylleberg and Kilburn 2003: 169. Dharma 2005: 248, pl. 99, fig. 13a-e; 364, pl. 147, fig. 3a, b. Thach 2005: 263, pl. 80, fig. 13. Nabhitabha-ta 2009: 342. Huber 2010: 203, with in-text fig. Huber 2015: C6118. BEDO 2017a: 236, with in-text fig. Yang et al. 2017: 172, fig. 667. Dijkstra and Beu 2018: 296-298, figs 98, 100j, l, 101d, e. Wells et al. 2021: 67.

**Referred material.** CUF-NKNY-B07 (32L+32R shells; Figs 12B, 14F).

**Habitat.** Byssally attached under coral boulders and rocks, on sand and sandy mud in intertidal zones down to 22 m depth (Huber 2015).

**Distribution.** Indo-West Pacific, from China to Australia (Huber 2015; Dijkstra and Beu 2018). Records of fossils from the Middle to Late Pliocene in Indonesia (Dharma 2005).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species, *Volachlamys tranquebaria* (Gmelin, 1791) and *V. hirasei* (Bavay, 1904), by having square and well-defined 18-24 ribs with wider interspaces between the ribs (Dharma 2005; Dijkstra and Beu 2018). See also comprehensive taxonomic remarks in Dijkstra and Beu (2018)

**Superorder Heteroconchia Gray, 1854**

**Order Lucinida Gray, 1854**

**Superfamily Lucinoidea J. Fleming, 1828**

**Family Lucinidae J. Fleming, 1828**

**Pegophysema Stewart, 1930**

**Pegophysema bialata (Pilsbry, 1895)**

Figs 13E, 15A

*Loripes bialata* Pilsbry, 1895: 133-134, pl. 3, figs 13, 14. Type locality: Inland Sea, Japan.

*Anodontia (?Pegophysema) bialata*. Taylor and Glover 2005: 305-306, figs 11a, 12a, 22, 23.

*Pegophysema bialata*. Huber 2015: 102, 455-456, with in-text figs; C10244. Wells et al. 2021: 35.

**Referred material.** CUF-NKNY-B11 (3L+3R shells; Figs 13E, 15A).

**Habitat.** Muddy bottoms and sandy mud among weed in intertidal zones down to 60 m depth (Huber 2015).
**Superfamily Pectinoidea Rafinesque, 1815**

**Family Pectinidae Rafinesque, 1815**

**Volachlamys Iredale, 1939**

**Volachlamys singaporina (Sowerby II, 1842)**

Figs 12B, 14F

*Pecten singaporinus* Sowerby II, 1842: 74, pl. 13, fig. 55; pl. 14, fig. 71. Type locality: Singapore. Lynge 1909: 155.

*Volachlamys singaporina*. Roussy 1991: 21. Poutiers 1998a: 210, with in-text figs. Aungtonya et al. 1999: 376. Swennen et al. 2001: 45, 74, fig. 70. Gemert 2003: 108. Hylleberg and Kilburn 2003: 169. Dharma 2005: 248, pl. 99, fig. 13a-e; 364, pl. 147, fig. 3a, b. Thach 2005: 263, pl. 80, fig. 13. Nabhitabha-ta 2009: 342. Huber 2010: 203, with in-text fig. Huber 2015: C6118. BEDO 2017a: 236, with in-text fig. Yang et al. 2017: 172, fig. 667. Dijkstra and Beu 2018: 296-298, figs 98, 100j, l, 101d, e. Wells et al. 2021: 67.

**Referred material.** CUF-NKNY-B07 (32L+32R shells; Figs 12B, 14F).

**Habitat.** Byssally attached under coral boulders and rocks, on sand and sandy mud in intertidal zones down to 22 m depth (Huber 2015).

**Distribution.** Indo-West Pacific, from China to Australia (Huber 2015; Dijkstra and Beu 2018). Records of fossils from the Middle to Late Pliocene in Indonesia (Dharma 2005).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species, *Volachlamys tranquebaria* (Gmelin, 1791) and *V. hirasei* (Bavay, 1904), by having square and well-defined 18-24 ribs with wider interspaces between the ribs (Dharma 2005; Dijkstra and Beu 2018). See also comprehensive taxonomic remarks in Dijkstra and Beu (2018).

**Superorder Heteroconchia Gray, 1854**

**Order Lucinida Gray, 1854**

**Superfamily Lucinoidea J. Fleming, 1828**

**Family Lucinidae J. Fleming, 1828**

**Pegophysema Stewart, 1930**

**Pegophysema bialata (Pilsbry, 1895)**

Figs 13E, 15A

*Loripes bialata* Pilsbry, 1895: 133-134, pl. 3, figs 13, 14. Type locality: Inland Sea, Japan.

*Anodontia (?Pegophysema) bialata*. Taylor and Glover 2005: 305-306, figs 11a, 12a, 22, 23.

*Pegophysema bialata*. Huber 2015: 102, 455-456, with in-text figs; C10244. Wells et al. 2021: 35.

**Referred material.** CUF-NKNY-B11 (3L+3R shells; Figs 13E, 15A).

**Habitat.** Muddy bottoms and sandy mud among weed in intertidal zones down to 60 m depth (Huber 2015).
**Distribution.** Indian Ocean; Indo-West Pacific, from Japan to Malaysia (Taylor and Glover 2005; Huber 2015).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species, *Pegophysema philippiana* (Reeve, 1850), by having a ligament that is shallowly inset and an absence of secondary pallial attachment scars (Taylor and Glover 2005). See also comprehensive taxonomic remarks in Taylor and Glover (2005).

**Order Venerida Gray, 1854**

**Superfamily Cyrenoidea Gray, 1840**

**Family Cyrenidae Gray, 1840**

**Geloina Gray, 1842**

**Geloina bengalensis (Lamarck, 1818)**

Figs 13C, 15B

*Cyrena bengalensis* Lamarck, 1818: 554. Type locality: Bengal.

*Polymesoda (Geloina) bengalensis*. Brandt 1974: 310–311, pl. 28, fig. 83. Nattewathana 1995: 106, with in-text fig. Aungtonya et al. 1999: 380. Robba et al. 2002: 106, pl. 16, fig. 9. Robba et al. 2003: tables 1, 2. Robba et al. 2007: 87 (appendix). Nabhitabhata 2009: 21, with in-text fig, 471.

*Polymesoda bengalensis*. Poutiers 1998a: 319, with in-text figs. Dharma 2005: 266, pl. 108, fig. 25. Dey 2006: 74–75, figs 113, 114. Tudu et al. 2018: table 1.

*Geloina bengalensis*. Huber 2015: 319; C20908. BEDO 2017a: 252, with in-text fig. Wells et al. 2021: 39.

**Referred material.** CUF-NKNY-B31 (2L+3R shells; Figs 13C, 15B).

**Habitat.** In intertidal zones, river deltas, estuaries, mud flats, and in mangrove areas (Poutiers 1998a; Huber 2015).

**Distribution.** Bay of Bengal; Indo-West Pacific, from Taiwan to Indonesia (Huber 2015). Records of fossils from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Robba et al. (2002) and Huber (2015), specifically in having a solid, inflated, pronounced inequilateral, and subtriangular shell shape.

**Superfamily Mactroidea Lamarck, 1809**

**Family Mactridae Lamarck, 1809**

**Lutraria Lamarck, 1799**

**Lutraria complanata (Gmelin, 1791)**

Figs 13H, 15C

*Mactra complanata* Gmelin, 1791: 3261. Type locality: the Indian Ocean.

*Lutraria (Lutrophora)* cf. *complanata*. Dheeradilok et al. 1984: pl. 2, fig. 5.

*Lutraria complanata*. Swennen et al. 2001: 47, 82, fig. 112. Hylleberg and Kilburn 2003: 186. Yang et al. 2017: 194, fig. 742. Wells et al. 2021: 40.
**Distribution.** Indian Ocean; Indo-West Pacific, from Japan to Malaysia (Taylor and Glover 2005; Huber 2015).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species, *Pegophysema philippiana* (Reeve, 1850), by having a ligament that is shallowly inset and an absence of secondary pallial attachment scars (Taylor and Glover 2005). See also comprehensive taxonomic remarks in Taylor and Glover (2005).

**Order Venerida Gray, 1854**

**Superfamily Cyrenoidea Gray, 1840**

**Family Cyrenidae Gray, 1840**

**Geloina Gray, 1842**

**Geloina bengalensis (Lamarck, 1818)**

Figs 13C, 15B

*Cyrena bengalensis* Lamarck, 1818: 554. Type locality: Bengal.

*Polymesoda (Geloina) bengalensis*. Brandt 1974: 310–311, pl. 28, fig. 83. Nattewathana 1995: 106, with in-text fig. Aungtonya et al. 1999: 380. Robba et al. 2002: 106, pl. 16, fig. 9. Robba et al. 2003: tables 1, 2. Robba et al. 2007: 87 (appendix). Nabhitabhata 2009: 21, with in-text fig, 471.

*Polymesoda bengalensis*. Poutiers 1998a: 319, with in-text figs. Dharma 2005: 266, pl. 108, fig. 25. Dey 2006: 74–75, figs 113, 114. Tudu et al. 2018: table 1.

*Geloina bengalensis*. Huber 2015: 319; C20908. BEDO 2017a: 252, with in-text fig. Wells et al. 2021: 39.

**Referred material.** CUF-NKNY-B31 (2L+3R shells; Figs 13C, 15B).

**Habitat.** In intertidal zones, river deltas, estuaries, mud flats, and in mangrove areas (Poutiers 1998a; Huber 2015).

**Distribution.** Bay of Bengal; Indo-West Pacific, from Taiwan to Indonesia (Huber 2015). Records of fossils from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Robba et al. (2002) and Huber (2015), specifically in having a solid, inflated, pronounced inequilateral, and subtriangular shell shape.

**Superfamily Mactroidea Lamarck, 1809**

**Family Mactridae Lamarck, 1809**

**Lutraria Lamarck, 1799**

**Lutraria complanata (Gmelin, 1791)**

Figs 13H, 15C

*Mactra complanata* Gmelin, 1791: 3261. Type locality: the Indian Ocean.

*Lutraria (Lutrophora)* cf. *complanata*. Dheeradilok et al. 1984: pl. 2, fig. 5.

*Lutraria complanata*. Swennen et al. 2001: 47, 82, fig. 112. Hylleberg and Kilburn 2003: 186. Yang et al. 2017: 194, fig. 742. Wells et al. 2021: 40.
<figure><img src="image_15.png" /><figcaption>**Figure 15.** Bivalves **A Pegophysema bialata** **B Geloina bengalensis** **C Lutraria complanata** **D Standella pellucida** **E Tellinides conspicuus** **F Joannisiella oblonga**.</figcaption></figure>

*Lutraria (Lutrophora) complanata*. Robba et al. 2002: 91, pl. 12, fig. 4. Robba et al. 2007: 86 (appendix). Huber 2010: 451, with in-text figs. Huber 2015: C21984.

*Lutraria (Goniomactra) complanata*. Beu 2006: 242.

*Lutraria (Lutropbora) complanata* [sic]. Nabhitabhata 2009: 412.
<figure><img src="image_16.png" /><figcaption>**Figure 15.** Bivalves **A Pegophysema bialata** **B Geloina bengalensis** **C Lutraria complanata** **D Standella pellucida** **E Tellinides conspicuus** **F Joannisiella oblonga**.</figcaption></figure>

*Lutraria (Lutrophora) complanata*. Robba et al. 2002: 91, pl. 12, fig. 4. Robba et al. 2007: 86 (appendix). Huber 2010: 451, with in-text figs. Huber 2015: C21984.

*Lutraria (Goniomactra) complanata*. Beu 2006: 242.

*Lutraria (Lutropbora) complanata* [sic]. Nabhitabhata 2009: 412.
**Referred material.** CUF-NKNY-B29 (1L+2R shells; Figs 13H, 15C).

**Habitat.** Sandy and muddy sand in subtidal zones from a depth of 8–20 m (Huber 2015).

**Distribution.** Indian Ocean; Indo-West Pacific, from South China to Indonesia (Huber 2015; Yang et al. 2017). Records of fossils from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Robba et al. (2002) and Huber (2010), specifically in having an elongate-elliptical and markedly inequilateral thin shell with arched anterior and posterior margins, and an outer surface sculptured with irregular crenulated growth lines.

**Standella Gray, 1853**

**Standella pellucida (Gmelin, 1791)**

Figs 13B, 15D

*Mactra pellucida* Gmelin, 1791: 3260–3261. Type locality: “Guinea coast.” Spanish 2011: table 2.

*Standella pellucida*. Lynge 1909: 224. Nabhitabhata 2009: 418. Huber 2010: 451, with in-text figs. Huber 2015: C22028. Tudu et al. 2018: table 1. Wells et al. 2021: 42.

*Meropesta pellucida*. Bosch et al. 1995: 248, fig. 1100. Poutiers 1998a: 281, with in-text figs. Swennen et al. 2001: 47, 83, text-fig. 116, fig. 116. Robba et al. 2002: 91–92, pl. 12, fig. 6. Dey and Ramakrishna 2007: 211. Robba et al. 2007: 86 (appendix). Meyer et al. 2008: tables 2, 3. Nabhitabhata 2009: 417. Wong 2009: 289, figs 9a, b, 22. BEDO 2017a: 155. Yang et al. 2017: 196, fig. 752.

**Referred material.** CUF-NKNY-B30 (1L+1R shells; Figs 13B, 15D).

**Habitat.** Fine sand and mud in intertidal zones down to 4 m depth, in lagoons, and at the fringe of mangrove areas (Poutiers 1998a; Huber 2015).

**Distribution.** Arabian Gulf and Indian Ocean; Indo-West Pacific, from Japan to Australia (Bosch et al. 1995; Wong 2009; Huber 2015). Records of fossils from the Quaternary in Indonesia and from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Robba et al. (2002) and Huber (2010), specifically in having a longer than high, inequilateral, and elliptical shell with an oval-shaped anterior margin and a somewhat pointed posterior margin, an outer surface sculptured with uneven and fine growth markings, and faint posterior radial striation. An exceedingly shallow radial depression is sometimes observed in the mid-anterior part. Huber (2015) indicated that the type locality in Guinea is erroneous.
**Referred material.** CUF-NKNY-B29 (1L+2R shells; Figs 13H, 15C).

**Habitat.** Sandy and muddy sand in subtidal zones from a depth of 8–20 m (Huber 2015).

**Distribution.** Indian Ocean; Indo-West Pacific, from South China to Indonesia (Huber 2015; Yang et al. 2017). Records of fossils from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Robba et al. (2002) and Huber (2010), specifically in having an elongate-elliptical and markedly inequilateral thin shell with arched anterior and posterior margins, and an outer surface sculptured with irregular crenulated growth lines.

**Standella Gray, 1853**

**Standella pellucida (Gmelin, 1791)**

Figs 13B, 15D

*Mactra pellucida* Gmelin, 1791: 3260–3261. Type locality: “Guinea coast.” Spanish 2011: table 2.

*Standella pellucida*. Lynge 1909: 224. Nabhitabhata 2009: 418. Huber 2010: 451, with in-text figs. Huber 2015: C22028. Tudu et al. 2018: table 1. Wells et al. 2021: 42.

*Meropesta pellucida*. Bosch et al. 1995: 248, fig. 1100. Poutiers 1998a: 281, with in-text figs. Swennen et al. 2001: 47, 83, text-fig. 116, fig. 116. Robba et al. 2002: 91–92, pl. 12, fig. 6. Dey and Ramakrishna 2007: 211. Robba et al. 2007: 86 (appendix). Meyer et al. 2008: tables 2, 3. Nabhitabhata 2009: 417. Wong 2009: 289, figs 9a, b, 22. BEDO 2017a: 155. Yang et al. 2017: 196, fig. 752.

**Referred material.** CUF-NKNY-B30 (1L+1R shells; Figs 13B, 15D).

**Habitat.** Fine sand and mud in intertidal zones down to 4 m depth, in lagoons, and at the fringe of mangrove areas (Poutiers 1998a; Huber 2015).

**Distribution.** Arabian Gulf and Indian Ocean; Indo-West Pacific, from Japan to Australia (Bosch et al. 1995; Wong 2009; Huber 2015). Records of fossils from the Quaternary in Indonesia and from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Robba et al. (2002) and Huber (2010), specifically in having a longer than high, inequilateral, and elliptical shell with an oval-shaped anterior margin and a somewhat pointed posterior margin, an outer surface sculptured with uneven and fine growth markings, and faint posterior radial striation. An exceedingly shallow radial depression is sometimes observed in the mid-anterior part. Huber (2015) indicated that the type locality in Guinea is erroneous.
**Superfamily Tellinoidea Blainville, 1814**

**Family Tellinidae Blainville, 1814**

**Tellinides Lamarck, 1818**

**Tellinides conspicuus (Hanley, 1846)**

Figs 13J, 15E

*Tellina conspicuca* Hanley, 1846b: 293, pl. 58, fig. 100. Type locality: unknown.
Coan and Kabat 2012: 309.

*Tellina* (*Tellinides*) sp. Robba et al. 2002: 98, pl. 14, fig. 7a, b.

*Tellinides conspicuus*. Huber 2015: 220, 639, with in-text figs; C14877. Wells et al. 2021: 30.

**Referred material.** CUF-NKNY-B04 (33L+40R shells; Figs 13J, 15E).

**Habitat.** Shallow water (Huber 2015).

**Distribution.** Indo-West Pacific, from southern China to New Guinea (Huber 2015).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** *Tellina* (*Tellinides*) sp. in Robba et al. (2002) was identified as belonging to this species by Huber (2015). This species differs from its similar species, *Tellinides timorensis* Lamarck, 1818, by having a higher shell that lacks the posterior truncation with oblique anterior striae fading posteriorly (Robba et al. 2002; Huber 2015).

**Superfamily Ungulinoidea Gray, 1854**

**Family Ungulinidae Gray, 1854**

**Joannisiella Dall, 1895**

**Joannisiella oblonga (Hanley, 1846)**

Figs 12S, 15F

*Cyrenoidea oblonga* Hanley, 1846a: 10 (plate explanation). Type locality: Philippines. Hanley 1856: 353, pl. 15, fig. 6. Coan and Kabat 2012: 320.

*Diplodonta* (*Joannisiella*) oblonga. Lynge 1909: 176.

*Cycladicama oblonga*. Dheeradilok et al. 1984: pl. 2, figs 6, 7. Robba et al. 2002: 79, pl. 7, fig. 9a, b. Hylleberg and Kilburn 2003: 174. Robba et al. 2003: tables 3, 4. Robba et al. 2007: 85 (appendix). Nabhitabhata 2009: 389. Yang et al. 2017: 182, fig. 704. Surakiatchai et al. 2018: table 6, pl. 3, fig. 10a, b.

*Joannisiella oblonga*. Huber 2015: 341, 829, with in-text figs; C21436. Wells et al. 2021: 42.

**Referred material.** CUF-NKNY-B09, B17 (59L+66R shells; Figs 12S, 15F).

**Habitat.** Muddy bottom with soft clay, muddy sediments on mud flats, and in the shallow waters from intertidal zones down to 36 m depth (Huber 2015; Yang et al. 2017).
**Superfamily Tellinoidea Blainville, 1814**

**Family Tellinidae Blainville, 1814**

**Tellinides Lamarck, 1818**

**Tellinides conspicuus (Hanley, 1846)**

Figs 13J, 15E

*Tellina conspicuca* Hanley, 1846b: 293, pl. 58, fig. 100. Type locality: unknown.
Coan and Kabat 2012: 309.

*Tellina* (*Tellinides*) sp. Robba et al. 2002: 98, pl. 14, fig. 7a, b.

*Tellinides conspicuus*. Huber 2015: 220, 639, with in-text figs; C14877. Wells et al. 2021: 30.

**Referred material.** CUF-NKNY-B04 (33L+40R shells; Figs 13J, 15E).

**Habitat.** Shallow water (Huber 2015).

**Distribution.** Indo-West Pacific, from southern China to New Guinea (Huber 2015).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** *Tellina* (*Tellinides*) sp. in Robba et al. (2002) was identified as belonging to this species by Huber (2015). This species differs from its similar species, *Tellinides timorensis* Lamarck, 1818, by having a higher shell that lacks the posterior truncation with oblique anterior striae fading posteriorly (Robba et al. 2002; Huber 2015).

**Superfamily Ungulinoidea Gray, 1854**

**Family Ungulinidae Gray, 1854**

**Joannisiella Dall, 1895**

**Joannisiella oblonga (Hanley, 1846)**

Figs 12S, 15F

*Cyrenoidea oblonga* Hanley, 1846a: 10 (plate explanation). Type locality: Philippines. Hanley 1856: 353, pl. 15, fig. 6. Coan and Kabat 2012: 320.

*Diplodonta (Joannisiella) oblonga*. Lynge 1909: 176.

*Cycladicama oblonga*. Dheeradilok et al. 1984: pl. 2, figs 6, 7. Robba et al. 2002: 79, pl. 7, fig. 9a, b. Hylleberg and Kilburn 2003: 174. Robba et al. 2003: tables 3, 4. Robba et al. 2007: 85 (appendix). Nabhitabhata 2009: 389. Yang et al. 2017: 182, fig. 704. Surakiatchai et al. 2018: table 6, pl. 3, fig. 10a, b.

*Joannisiella oblonga*. Huber 2015: 341, 829, with in-text figs; C21436. Wells et al. 2021: 42.

**Referred material.** CUF-NKNY-B09, B17 (59L+66R shells; Figs 12S, 15F).

**Habitat.** Muddy bottom with soft clay, muddy sediments on mud flats, and in the shallow waters from intertidal zones down to 36 m depth (Huber 2015; Yang et al. 2017).
**Distribution.** Indo-West Pacific, from Japan to Indonesia and the Philippines (Huber 2015; Yang et al. 2017). Records of fossils from the Middle Miocene to Holocene in Indonesia, Japan, the Philippines, Taiwan, and Thailand (Robba et al. 2002; Surakiatchai et al. 2018).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is characterised by its elongate, ovate-triangular shaped, and posteriorly grooved shell (Robba et al. 2002; Huber 2015).

**Superfamily Veneroidea Rafinesque, 1815**

**Family Veneridae Rafinesque, 1815**

**Dosinia Scopoli, 1777**

**Dosinia dilecta A. Adams, 1856**

Figs 12R, 16A

*Dosinia dilecta* A. Adams, 1856: 224. Type locality: Malacca. Lynge 1909: 249–250, pl. 5, figs 11–13. Morris and Purchon 1981: 326. Swennen et al. 2001: 49, 95, text-fig. 201, fig. 201. Robba et al. 2002: 115, pl. 19, fig. 4. Dharma 2005: 266, pl. 108, fig. 30. Robba et al. 2007: 88 (appendix). Sartori et al. 2008: table 1. Nabhitabhata 2009: 482. Poppe 2010c: 304, pl. 1147, figs 5, 6. Surakiatchai et al. 2018: table 6, pl. 5, fig. 8a, b. Wells et al. 2021: 44.

*Dosinia* (*Dosinella*) *dilecta*. Fischer-Piette and Delmas 1967: 77, pl. 14, figs 1–3. Dheeradilok et al. 1984: pl. 2, figs 9–12. Huber 2010: 414, with in-text fig. Huber 2015: C19500.

**Referred material.** CUF-NKNY-B10 (2L+5R shells; Figs 12R, 16A).

**Habitat.** Soft clay and mud bottoms in subtidal zones at a depth from 5 to 20 m (Huber 2015).

**Distribution.** Indo-West Pacific, from southern China to Indonesia (Huber 2015). Records of fossils from the Holocene in Thailand (Robba et al. 2002; Surakiatchai et al. 2018).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Fischer-Piette and Delmas (1967), Robba et al. (2002), and Huber (2010), specifically in having deeply demarcated and exceedingly small lunulae and a shell with low concentric ribs. See also comprehensive taxonomic remarks in Fischer-Piette and Delmas (1967).

**Paratapes Stoliczka, 1870**

**Paratapes undulatus (Born, 1778)**

Figs 12Q, 16B

*Venus undulata* Born, 1778: 54–55. Type locality: unknown.

*Tapes (Paratapes) undulatus*. Lynge 1909: 237.

*Paphia undulata*. Tantanasiriwong 1979: 13. Morris and Purchon 1981: 326. Nateewathana et al. 1981: 67. Dheeradilok et al. 1984: pl. 2, fig. 13. Oliver 1992: 191, pl. 43, fig. 6a, b. Bosch et al. 1995: 273, fig. 1227. Nateewathana 1995:
**Distribution.** Indo-West Pacific, from Japan to Indonesia and the Philippines (Huber 2015; Yang et al. 2017). Records of fossils from the Middle Miocene to Holocene in Indonesia, Japan, the Philippines, Taiwan, and Thailand (Robba et al. 2002; Surakiatchai et al. 2018).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is characterised by its elongate, ovate-triangular shaped, and posteriorly grooved shell (Robba et al. 2002; Huber 2015).

**Superfamily Veneroidea Rafinesque, 1815**

**Family Veneridae Rafinesque, 1815**

**Dosinia Scopoli, 1777**

**Dosinia dilecta A. Adams, 1856**

Figs 12R, 16A

*Dosinia dilecta* A. Adams, 1856: 224. Type locality: Malacca. Lynge 1909: 249–250, pl. 5, figs 11–13. Morris and Purchon 1981: 326. Swennen et al. 2001: 49, 95, text-fig. 201, fig. 201. Robba et al. 2002: 115, pl. 19, fig. 4. Dharma 2005: 266, pl. 108, fig. 30. Robba et al. 2007: 88 (appendix). Sartori et al. 2008: table 1. Nabhitabhata 2009: 482. Poppe 2010c: 304, pl. 1147, figs 5, 6. Surakiatchai et al. 2018: table 6, pl. 5, fig. 8a, b. Wells et al. 2021: 44.

*Dosinia* (*Dosinella*) *dilecta*. Fischer-Piette and Delmas 1967: 77, pl. 14, figs 1–3. Dheeradilok et al. 1984: pl. 2, figs 9–12. Huber 2010: 414, with in-text fig. Huber 2015: C19500.

**Referred material.** CUF-NKNY-B10 (2L+5R shells; Figs 12R, 16A).

**Habitat.** Soft clay and mud bottoms in subtidal zones at a depth from 5 to 20 m (Huber 2015).

**Distribution.** Indo-West Pacific, from southern China to Indonesia (Huber 2015). Records of fossils from the Holocene in Thailand (Robba et al. 2002; Surakiatchai et al. 2018).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Fischer-Piette and Delmas (1967), Robba et al. (2002), and Huber (2010), specifically in having deeply demarcated and exceedingly small lunulae and a shell with low concentric ribs. See also comprehensive taxonomic remarks in Fischer-Piette and Delmas (1967).

**Paratapes Stoliczka, 1870**

**Paratapes undulatus (Born, 1778)**

Figs 12Q, 16B

*Venus undulata* Born, 1778: 54–55. Type locality: unknown.

*Tapes (Paratapes) undulatus*. Lynge 1909: 237.

*Paphia undulata*. Tantanasiriwong 1979: 13. Morris and Purchon 1981: 326. Nateewathana et al. 1981: 67. Dheeradilok et al. 1984: pl. 2, fig. 13. Oliver 1992: 191, pl. 43, fig. 6a, b. Bosch et al. 1995: 273, fig. 1227. Nateewathana 1995:
111, with in-text fig. Poutiers 1998a: 339, with in-text figs. Aungtonya et al. 1999: 382. Subba Rao and Dey 2000: 283. Swennen et al. 2001: 49, 95, text-fig. 198, fig. 198. Hylleberg and Kilburn 2003: 217. Dharma 2005: 270, pl. 110, fig. 16; 368, pl. 149, fig. 13. Thach 2005: 300, pl. 90, fig. 3. Dey and Ramakrishna 2007: 160, 244–245. Nabhitabhata 2009: 492. Poppe 2010c: 296, pl. 1143, figs 7–9. Sanpanich 2011: table 2. Okutani 2017: 1248, pl. 543, fig. 4. Yang et al. 2017: 232, fig. 871. Surakiatchai et al. 2018: table 6, pl. 5, fig. 4a, b.

*Paphia* cf. *undulata*. Aungtonya and Hylleberg 1998: 320.

*Paphia* (*Paphia*) *undulata*. Gemert 2003: 109. Robba et al. 2002: 113, pl. 18, fig. 8a, b. Robba et al. 2003: tables 1, 3–5. Robba et al. 2007: 88 (appendix). Negri et al. 2014: table 3.

*Neotapes* *undulata*. Sartori et al. 2008: 115, table 1, figs 4I, 5I.

*Paphia* (*Neotapes*) *undulata*. Huber 2010: 423, with in-text fig.

*Paratapes undulatus*. Huber 2015: C19932. Tudu et al. 2018: table 1. Wells et al. 2021: 47.

*Paratapes undulata*. BEDO 2017a: 281, with in-text fig.

**Referred material.** CUF-NKNY-B12 (2L shells; Figs 12Q, 16B).

**Habitat.** Fine sandy sediments and mud as well as silty clay bottoms in intertidal to subtidal zones at a depth of 1–50 m (Huber 2015).

**Distribution.** Red Sea and Indian Ocean; Indo-West Pacific, from Japan to Australia (Robba et al. 2002; Huber 2015). Records of fossils from the Late Miocene to Holocene in Indonesia, Japan, the Philippines, Taiwan, and Thailand (Robba et al. 2002; Dharma 2005; Surakiatchai et al. 2018).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** Despite having no colour and patterns, the elongate-oval and inequilateral shell shape with growth lines as well as slightly oblique and somewhat undulating commarginal grooves on outer surface of the specimens conform to the characters of this species (Robba et al. 2002; Huber 2010).

## Placamen Iredale, 1925

### Placamen lamellatum (Röding, 1798)

Figs 12L, 16C

*Venus lamellata* Röding, 1798: 183. Type locality: the East Indian Seas.

*Venus tiara* Dillwyn, 1817: 162. Type locality: the East Indian Seas.

*Venus calophylla* Philippi, 1836: 229–230, pl. 8, fig. 2 Type locality: the Chinese Sea.

*Chione* (*Circomphalus*) *calophylla*. Lynge 1909: 150–151.

*Callanaitis calophylla*. Tantanasiriwong 1979: 13. Nateewathana et al. 1981: 67.

*Placamen tiara*. Tantanasiriwong 1979: 13. Nateewathana et al. 1981: 67. Poutiers 1998a: 351, with in-text figs. Aungtonya et al. 1999: 382. Hylleberg and Kilburn 2003: 219. Dharma 2005: 268, pl. 109, fig. 24. Thach 2005: 292. Dey and Ramakrishna 2007: 159, 238. Nabhitabhata 2009: 495. Poppe 2010c: 274, pl. 1132, figs 1–3.

*Bassina calophylla*. Bosch et al. 1995: 266, fig. 1191. Subba Rao and Dey 2000: 284.
111, with in-text fig. Poutiers 1998a: 339, with in-text figs. Aungtonya et al. 1999: 382. Subba Rao and Dey 2000: 283. Swennen et al. 2001: 49, 95, text-fig. 198, fig. 198. Hylleberg and Kilburn 2003: 217. Dharma 2005: 270, pl. 110, fig. 16; 368, pl. 149, fig. 13. Thach 2005: 300, pl. 90, fig. 3. Dey and Ramakrishna 2007: 160, 244–245. Nabhitabhata 2009: 492. Poppe 2010c: 296, pl. 1143, figs 7–9. Sanpanich 2011: table 2. Okutani 2017: 1248, pl. 543, fig. 4. Yang et al. 2017: 232, fig. 871. Surakiatchai et al. 2018: table 6, pl. 5, fig. 4a, b.

*Paphia* cf. *undulata*. Aungtonya and Hylleberg 1998: 320.

*Paphia* (*Paphia*) *undulata*. Gemert 2003: 109. Robba et al. 2002: 113, pl. 18, fig. 8a, b. Robba et al. 2003: tables 1, 3–5. Robba et al. 2007: 88 (appendix). Negri et al. 2014: table 3.

*Neotapes* *undulata*. Sartori et al. 2008: 115, table 1, figs 4I, 5I.

*Paphia* (*Neotapes*) *undulata*. Huber 2010: 423, with in-text fig.

*Paratapes undulatus*. Huber 2015: C19932. Tudu et al. 2018: table 1. Wells et al. 2021: 47.

*Paratapes undulata*. BEDO 2017a: 281, with in-text fig.

**Referred material.** CUF-NKNY-B12 (2L shells; Figs 12Q, 16B).

**Habitat.** Fine sandy sediments and mud as well as silty clay bottoms in intertidal to subtidal zones at a depth of 1–50 m (Huber 2015).

**Distribution.** Red Sea and Indian Ocean; Indo-West Pacific, from Japan to Australia (Robba et al. 2002; Huber 2015). Records of fossils from the Late Miocene to Holocene in Indonesia, Japan, the Philippines, Taiwan, and Thailand (Robba et al. 2002; Dharma 2005; Surakiatchai et al. 2018).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** Despite having no colour and patterns, the elongate-oval and inequilateral shell shape with growth lines as well as slightly oblique and somewhat undulating commarginal grooves on outer surface of the specimens conform to the characters of this species (Robba et al. 2002; Huber 2010).

Placamen Iredale, 1925

Placamen lamellatum (Röding, 1798)

Figs 12L, 16C

*Venus lamellata* Röding, 1798: 183. Type locality: the East Indian Seas.

*Venus tiara* Dillwyn, 1817: 162. Type locality: the East Indian Seas.

*Venus calophylla* Philippi, 1836: 229–230, pl. 8, fig. 2 Type locality: the Chinese Sea.

*Chione* (*Circomphalus*) *calophylla*. Lynge 1909: 150–151.

*Callanaitis calophylla*. Tantanasiriwong 1979: 13. Nateewathana et al. 1981: 67.

*Placamen tiara*. Tantanasiriwong 1979: 13. Nateewathana et al. 1981: 67. Poutiers 1998a: 351, with in-text figs. Aungtonya et al. 1999: 382. Hylleberg and Kilburn 2003: 219. Dharma 2005: 268, pl. 109, fig. 24. Thach 2005: 292. Dey and Ramakrishna 2007: 159, 238. Nabhitabhata 2009: 495. Poppe 2010c: 274, pl. 1132, figs 1–3.

*Bassina calophylla*. Bosch et al. 1995: 266, fig. 1191. Subba Rao and Dey 2000: 284.
*Placamen calophyllum*. Kilburn and Hylleberg 1998: 315. Aungtonya et al. 1999: 382. Swennen et al. 2001: 48, 92, fig. 180. Robba et al. 2002: 107, pl. 17, fig. 4. Gemert 2003: 15. Hylleberg and Kilburn 2003: 218–219. Dharma 2005: 268, pl. 109, fig. 25. Thach 2005: 292, pl. 89, fig. 11. Robba et al. 2007: 87 (appendix). Meyer et al. 2008: tables 2, 4. Sartori et al. 2008: table 1. Nabhitabhata 2009: 494. Poppe 2010c: 272, pl. 1131, figs 4–7. Sanpanich 2011: table 2.

*Placamen lamellatum*. Huber 2010: 369, with in-text figs. Huber 2015: C18043. BEDO 2017a: 287. Tudu et al. 2018: table 1. Wells et al. 2021: 48.

*Clausinella calophylla*. Yang et al. 2017: 222, 224, fig. 834.

*Clausinella tiara*. Yang et al. 2017: 224, fig. 836.

**Referred material.** CUF-NKNY-B28 (1R shell; Figs 12L, 16C).

**Habitat.** Muddy sand, sand, and shell gravels from intertidal zones down to 100 m depth (Bosch et al. 1995; Robba et al. 2002; Yang et al. 2017).

**Distribution.** Arabian Gulf and Indian Ocean; Indo-West Pacific, from Japan to Indonesia (Bosch et al. 1995; Huber 2015; Yang et al. 2017). Records of fossils from the Late Neogene to Holocene in Fiji, India, Indonesia, Japan, the Philippines and Taiwan (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species, *Placamen chloroticum* (Philippi, 1849), by having a somewhat shallower and trigonal pallial sinus as well as more widely spaced and more raised commarginal lamellae (Robba et al. 2002).

## Order Myida Stoliczka, 1870

### Superfamily Myoidea Lamarck, 1809

### Family Corbulidae Lamarck, 1818

### Corbula Bruguière, 1797

### Corbula fortisulcata Smith, 1879

Figs 12J, 16D

*Corbula fortisulcata* Smith, 1879a: 819–820, pl. 50, fig. 23, 23b. Type locality: the Andaman Islands. Subba Rao and Dey 2000: 286. Swennen et al. 2001: 49, 97, text-fig. 212, fig. 212. Hylleberg and Kilburn 2003: 222. Poppe 2010b: 388, pl. 1189, figs 6, 7a, b. Yang et al. 2017: 240, 242, fig. 899. Surakiatchai et al. 2018: table 6, pl. 5, fig. 10a, b. Wells et al. 2021: 36.

*Corbula (Corbula) fortisulcata*. Robba et al. 2002: 117–118, pl. 20, fig. 5. Robba et al. 2003: table 3. Robba et al. 2007: 88 (appendix). Nabhitabhata 2009: 506.

*Corbula (Notocorbula) cf. fortisulcata*. Thach 2005: 303, pl. 91, fig. 4.

*Corbula (Notocorbula) fortisulcata*. Huber 2010: 467, with in-text fig. Huber 2015: C22606.

**Referred material.** CUF-NKNY-B19 (154 shells; Figs 12J, 16D).

**Habitat.** Fine sand, sandy mud and muddy bottoms at intertidal to sublittoral zones at a depth from 1 to 70 m (Huber 2015).

**Distribution.** Indian Ocean; Indo-West Pacific, from Taiwan to Australia (Huber 2015). Records of fossils from the Late Miocene in the Philippines and from the Holocene in Thailand (Robba et al. 2002; Surakiatchai et al. 2018).
*Placamen calophyllum*. Kilburn and Hylleberg 1998: 315. Aungtonya et al. 1999: 382. Swennen et al. 2001: 48, 92, fig. 180. Robba et al. 2002: 107, pl. 17, fig. 4. Gemert 2003: 15. Hylleberg and Kilburn 2003: 218–219. Dharma 2005: 268, pl. 109, fig. 25. Thach 2005: 292, pl. 89, fig. 11. Robba et al. 2007: 87 (appendix). Meyer et al. 2008: tables 2, 4. Sartori et al. 2008: table 1. Nabhitabhata 2009: 494. Poppe 2010c: 272, pl. 1131, figs 4–7. Sanpanich 2011: table 2.

*Placamen lamellatum*. Huber 2010: 369, with in-text figs. Huber 2015: C18043. BEDO 2017a: 287. Tudu et al. 2018: table 1. Wells et al. 2021: 48.

*Clausinella calophylla*. Yang et al. 2017: 222, 224, fig. 834.

*Clausinella tiara*. Yang et al. 2017: 224, fig. 836.

**Referred material.** CUF-NKNY-B28 (1R shell; Figs 12L, 16C).

**Habitat.** Muddy sand, sand, and shell gravels from intertidal zones down to 100 m depth (Bosch et al. 1995; Robba et al. 2002; Yang et al. 2017).

**Distribution.** Arabian Gulf and Indian Ocean; Indo-West Pacific, from Japan to Indonesia (Bosch et al. 1995; Huber 2015; Yang et al. 2017). Records of fossils from the Late Neogene to Holocene in Fiji, India, Indonesia, Japan, the Philippines and Taiwan (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species differs from its similar species, *Placamen chloroticum* (Philippi, 1849), by having a somewhat shallower and trigonal pallial sinus as well as more widely spaced and more raised commarginal lamellae (Robba et al. 2002).

**Order Myida Stoliczka, 1870**

**Superfamily Myoidea Lamarck, 1809**

**Family Corbulidae Lamarck, 1818**

**Corbula Bruguière, 1797**

**Corbula fortisulcata Smith, 1879**

Figs 12J, 16D

*Corbula fortisulcata* Smith, 1879a: 819–820, pl. 50, fig. 23, 23b. Type locality: the Andaman Islands. Subba Rao and Dey 2000: 286. Swennen et al. 2001: 49, 97, text-fig. 212, fig. 212. Hylleberg and Kilburn 2003: 222. Poppe 2010b: 388, pl. 1189, figs 6, 7a, b. Yang et al. 2017: 240, 242, fig. 899. Surakiatchai et al. 2018: table 6, pl. 5, fig. 10a, b. Wells et al. 2021: 36.

*Corbula (Corbula) fortisulcata*. Robba et al. 2002: 117–118, pl. 20, fig. 5. Robba et al. 2003: table 3. Robba et al. 2007: 88 (appendix). Nabhitabhata 2009: 506.

*Corbula (Notocorbula) cf. fortisulcata*. Thach 2005: 303, pl. 91, fig. 4.

*Corbula (Notocorbula) fortisulcata*. Huber 2010: 467, with in-text fig. Huber 2015: C22606.

**Referred material.** CUF-NKNY-B19 (154 shells; Figs 12J, 16D).

**Habitat.** Fine sand, sandy mud and muddy bottoms at intertidal to sublittoral zones at a depth from 1 to 70 m (Huber 2015).

**Distribution.** Indian Ocean; Indo-West Pacific, from Taiwan to Australia (Huber 2015). Records of fossils from the Late Miocene in the Philippines and from the Holocene in Thailand (Robba et al. 2002; Surakiatchai et al. 2018).
<figure><img src="image_16.png" /><figcaption>**Figure 16.** Bivalves **A Dosinia dilecta** **B Paratapes undulatus** **C Placamen lamellatum** **D Corbula fortisulcata** **E Potamocorbula** sp. **F, G Martesia striata** **G** showing the shells with burrow casts along with mangrove roots **H Pholas orientalis** **I** calcareous burrows of Teredinidae indet.</figcaption></figure>

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).
**Taxonomic remarks and comparisons.** This species differs from its similar species, *Corbula tunicata* Reeve, 1843, by having a weaker keel on the juvenile shell part (Swennen et al. 2001).
<figure><img src="image_17.png" /><figcaption>**Figure 16.** Bivalves **A Dosinia dilecta** **B Paratapes undulatus** **C Placamen lamellatum** **D Corbula fortisulcata** **E Potamocorbula** sp. **F, G Martesia striata** **G** showing the shells with burrow casts along with mangrove roots **H Pholas orientalis** **I** calcareous burrows of Teredinidae indet.</figcaption></figure>

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).
**Taxonomic remarks and comparisons.** This species differs from its similar species, *Corbula tunicata* Reeve, 1843, by having a weaker keel on the juvenile shell part (Swennen et al. 2001).
**Potamocorbula Habe, 1955**

**Potamocorbula sp.**
Figs 12N, 16E

**Referred material.** CUF-NKNY-B26 (112 shells; Figs 12N, 16E).

**Habitat.** Mostly present in intertidal zones, estuarine and brackish habitats
(Huber 2015).

**Distribution.** This genus is mostly distributed in the Indian Ocean and In-
do-West Pacific, except for the species *Potamocorbula adusta* (Reeve, 1844),
which is recorded only from West Africa (Huber 2015).

**Taxonomic remarks and comparisons.** These specimens are assigned to *Potamocorbula* based on the descriptions in Coan (2002), specifically in having smooth shells. Currently, there are a total of nine species in this genus (Huber 2015; MolluscaBase 2023), in which two species, *P. fasciata* (Reeve, 1843) and *P. laevis* (Hinds, 1843), are recorded from Thailand (Wells et al. 2021). However, our specimens have a more quadrate shell shape, probably suggesting the presence of other different species.

**Superfamily Pholadoidea Lamarck, 1809**

**Family Pholadidae Lamarck, 1809**

**Martesia Sowerby I, 1824**

**Martesia striata** (Linnaeus, 1758)
Figs 12M, 16F, G

*Pholas striatus* Linnaeus, 1758: 669. Type locality: southern Europe.

*Pholas* (*Martesia*) *striata*. Lynge 1909: 283–284.

*Martesia striata*. Cernohorsky 1978: 188, pl. 68, fig. 4. Morris and Purchon 1981: 327. Oliver 1992: 203, pl. 45, fig. 4a, b. Bosch et al. 1995: 279, fig. 1263. Yoosukh and Jitkaew 1997: 402, fig. 1a, b. Poutiers 1998a: 358, with in-text figs. Subba Rao and Dey 2000: 287. Swennen et al. 2001: 49, 99, fig. 223. Hyl-leberg and Kilburn 2003: 224. Dey and Ramakrishna 2007: 161, 252. Nabhi-tabhata 2009: 21, with in-text fig, 509. Haga 2010: 394, pl. 1192, figs 3, 4. Gopalakrishnan et al. 2012: 61. Okutani 2017: 1270, pl. 563, fig. 5. Yang et al. 2017: 246, fig. 914. Tudu et al. 2018: table 1. Wells et al. 2021: 37.

*Martesia* (*Martesia*) *striata*. Robba et al. 2002: 121–122, pl. 21, fig. 7a. Thach 2005: 304, pl. 91, fig. 10. Robba et al. 2007: 23, fig. 9p; 88 (appendix). Huber 2010: 476, with in-text figs. Huber 2015: C22956.

**Referred material.** CUF-NKNY-B14 (8L+8R shells; Figs 12M, 16F, G).

**Habitat.** Bored in old wood pilings, waterlogged tree trunks, and in driftwood but rarely in astreid corals, in soft rocks, or mangroves *Rhizophora stylosa*; from intertidal zones down to 20 m depth (Huber 2015).

**Distribution.** Cosmopolitan (Huber 2015). Records of fossils from the Middle Miocene to Holocene in Japan, Indonesia, New Hebrides, and Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).
**Potamocorbula Habe, 1955**

**Potamocorbula sp.**
Figs 12N, 16E

**Referred material.** CUF-NKNY-B26 (112 shells; Figs 12N, 16E).

**Habitat.** Mostly present in intertidal zones, estuarine and brackish habitats
(Huber 2015).

**Distribution.** This genus is mostly distributed in the Indian Ocean and In-
do-West Pacific, except for the species *Potamocorbula adusta* (Reeve, 1844),
which is recorded only from West Africa (Huber 2015).

**Taxonomic remarks and comparisons.** These specimens are assigned to *Potamocorbula* based on the descriptions in Coan (2002), specifically in having smooth shells. Currently, there are a total of nine species in this genus (Huber 2015; MolluscaBase 2023), in which two species, *P. fasciata* (Reeve, 1843) and *P. laevis* (Hinds, 1843), are recorded from Thailand (Wells et al. 2021). However, our specimens have a more quadrate shell shape, probably suggesting the presence of other different species.

**Superfamily Pholadoidea Lamarck, 1809**

**Family Pholadidae Lamarck, 1809**

**Martesia Sowerby I, 1824**

**Martesia striata** (Linnaeus, 1758)
Figs 12M, 16F, G

*Pholas striatus* Linnaeus, 1758: 669. Type locality: southern Europe.

*Pholas* (*Martesia*) *striata*. Lynge 1909: 283–284.

*Martesia striata*. Cernohorsky 1978: 188, pl. 68, fig. 4. Morris and Purchon 1981: 327. Oliver 1992: 203, pl. 45, fig. 4a, b. Bosch et al. 1995: 279, fig. 1263. Yoosukh and Jitkaew 1997: 402, fig. 1a, b. Poutiers 1998a: 358, with in-text figs. Subba Rao and Dey 2000: 287. Swennen et al. 2001: 49, 99, fig. 223. Hylleberg and Kilburn 2003: 224. Dey and Ramakrishna 2007: 161, 252. Nabhitabhata 2009: 21, with in-text fig, 509. Haga 2010: 394, pl. 1192, figs 3, 4. Gopalakrishnan et al. 2012: 61. Okutani 2017: 1270, pl. 563, fig. 5. Yang et al. 2017: 246, fig. 914. Tudu et al. 2018: table 1. Wells et al. 2021: 37.

*Martesia* (*Martesia*) *striata*. Robba et al. 2002: 121–122, pl. 21, fig. 7a. Thach 2005: 304, pl. 91, fig. 10. Robba et al. 2007: 23, fig. 9p; 88 (appendix). Huber 2010: 476, with in-text figs. Huber 2015: C22956.

**Referred material.** CUF-NKNY-B14 (8L+8R shells; Figs 12M, 16F, G).

**Habitat.** Bored in old wood pilings, waterlogged tree trunks, and in driftwood but rarely in astreid corals, in soft rocks, or mangroves *Rhizophora stylosa*; from intertidal zones down to 20 m depth (Huber 2015).

**Distribution.** Cosmopolitan (Huber 2015). Records of fossils from the Middle Miocene to Holocene in Japan, Indonesia, New Hebrides, and Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).
**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Poutiers (1998a), Robba et al. (2002), and Huber (2010), specifically in having an outer surface bearing a radial groove at the anterior one-third of the shell, sculptured with commarginal ridges that are minutely nodose and anterior to the radial groove with nodes arranged into radial rows.

**Pholas Linnaeus, 1758**

**Pholas orientalis Gmelin, 1791**

Figs 12U, 16H

*Pholas orientalis* Gmelin, 1791: 3216. Type locality: Siam [Thailand] and Tranquebar. Morris and Purchon 1981: 327. Nateewathana 1995: 111, with in-text fig. Poutiers 1998a: 356, with in-text figs. Subba Rao and Dey 2000: 286. Swennen et al. 2001: 50, 98, fig. 219. Haga 2010: 396, pl. 1193, figs 2, 3. BEDO 2017a: 168, with in-text fig. Hylleberg and Kilburn 2003: 224. Dey and Ramakrishna 2007: 160, 251–252. Nabhitabhata 2009: 510. Gopalakrishnan et al. 2012: 61. Yang et al. 2017: 246, fig. 916. Tudu et al. 2018: table 1. Wells et al. 2021: 37.

*Pholas siamensis* Spengler, 1792: 88–89. Type locality: the Gulf of Thailand, the mouth of the river Qweda, where it goes up to Alastav. Knudsen and Jensen 2001: 547–556, figs 1–4.

*Pholas (Monothyra) orientalis*. Lynge 1909: 282. Aungtonya et al. 1999: 383. Robba et al. 2002: 121, pl. 21, fig. 5. Robba et al. 2003: tables 3–5. Dharma 2005: 270, pl. 110, fig. 25; 368, pl. 149, fig. 18a, b. Thach 2005: 304, pl. 91, fig. 6. Robba et al. 2007: 88 (appendix). Huber 2010: 473, with in-text fig. Huber 2015: C22846.

**Referred material.** CUF-NKNY-B05 (26L+73R shells; Figs 12U, 16H).

**Habitat.** Boring down to 50 cm depth in peat, soft rocks, stiff clay, or sticky and soft sandy-mud bottoms rich in silt and detritus, often near river mouths, from intertidal and sublittoral zones at a depth from 1 to 30 m (Poutiers 1998a; Huber 2015).

**Distribution.** Indian Ocean; Indo-West Pacific, from Taiwan to Australia (Huber 2015). Records of fossils from the Middle Miocene to Holocene in Indonesia, Myanmar, and Thailand (Robba et al. 2002; Dharma 2005).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Poutiers (1998a), Swennen et al. (2001), and Robba et al. (2002), specifically in having antero-dorsal reflection that has axial supports.

**Famliy Teredinidae Rafinesque, 1815**

**Teredinidae indet.**

Fig. 16I

**Referred material.** CUF-NKNY-B14-4 (83 tube pieces; Fig. 16I).
**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Poutiers (1998a), Robba et al. (2002), and Huber (2010), specifically in having an outer surface bearing a radial groove at the anterior one-third of the shell, sculptured with commarginal ridges that are minutely nodose and anterior to the radial groove with nodes arranged into radial rows.

**Pholas Linnaeus, 1758**

**Pholas orientalis Gmelin, 1791**

Figs 12U, 16H

*Pholas orientalis* Gmelin, 1791: 3216. Type locality: Siam [Thailand] and Tranquebar. Morris and Purchon 1981: 327. Nateewathana 1995: 111, with in-text fig. Poutiers 1998a: 356, with in-text figs. Subba Rao and Dey 2000: 286. Swennen et al. 2001: 50, 98, fig. 219. Haga 2010: 396, pl. 1193, figs 2, 3. BEDO 2017a: 168, with in-text fig. Hylleberg and Kilburn 2003: 224. Dey and Ramakrishna 2007: 160, 251–252. Nabhitabhata 2009: 510. Gopalakrishnan et al. 2012: 61. Yang et al. 2017: 246, fig. 916. Tudu et al. 2018: table 1. Wells et al. 2021: 37.

*Pholas siamensis* Spengler, 1792: 88–89. Type locality: the Gulf of Thailand, the mouth of the river Qweda, where it goes up to Alastav. Knudsen and Jensen 2001: 547–556, figs 1–4.

*Pholas (Monothyra) orientalis*. Lynge 1909: 282. Aungtonya et al. 1999: 383. Robba et al. 2002: 121, pl. 21, fig. 5. Robba et al. 2003: tables 3–5. Dharma 2005: 270, pl. 110, fig. 25; 368, pl. 149, fig. 18a, b. Thach 2005: 304, pl. 91, fig. 6. Robba et al. 2007: 88 (appendix). Huber 2010: 473, with in-text fig. Huber 2015: C22846.

**Referred material.** CUF-NKNY-B05 (26L+73R shells; Figs 12U, 16H).

**Habitat.** Boring down to 50 cm depth in peat, soft rocks, stiff clay, or sticky and soft sandy-mud bottoms rich in silt and detritus, often near river mouths, from intertidal and sublittoral zones at a depth from 1 to 30 m (Poutiers 1998a; Huber 2015).

**Distribution.** Indian Ocean; Indo-West Pacific, from Taiwan to Australia (Huber 2015). Records of fossils from the Middle Miocene to Holocene in Indonesia, Myanmar, and Thailand (Robba et al. 2002; Dharma 2005).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Poutiers (1998a), Swennen et al. (2001), and Robba et al. (2002), specifically in having antero-dorsal reflection that has axial supports.

**Famliy Teredinidae Rafinesque, 1815**

**Teredinidae indet.**

Fig. 16I

**Referred material.** CUF-NKNY-B14-4 (83 tube pieces; Fig. 16I).
**Habitat.** Boring into submerged wood and other plant material (Poutiers 1998a).

**Taxonomic remarks and comparisons.** The calcareous burrows have a septum dividing the cavity in half, indicating that these burrows belong to the shipworm family Teredinidae (e.g., Chan and Lau 2021). Due to the absence of shells, it is impossible to assign the inhabitants to species or even genus level based on these trace fossils.

**Order Adapedonta Cossmann & Peyrot, 1909**

**Superfamily Solenoidea Lamarck, 1809**

**Family Pharidae H. Adams & A. Adams, 1856**

**Cultellus Schumacher, 1817**

**Cultellus maximus (Gmelin, 1791)**

Figs 13G, 17A

*Solen maximus* Gmelin, 1791: 3227. Type locality: Nicobar.

*Solen lacteus* Spengler, 1794: 94–95. Type locality: Nicobar.

*Cultellus lacteus*. Tantanasiriwong 1979: 11. Morris and Purchon 1981: 325. Nateewathana et al. 1981: 66. Aungtonya et al. 1999: 379. Robba et al. 2002: 92, pl. 12, fig. 10. Robba et al. 2007: 86 (appendix). Nabhitabhata 2009: 423.

*Cultellus maximus*. Subba Rao and Dey 2000: 251. Swennen et al. 2001: 47, 83, text-fig. 121, fig. 121. Huber 2010: 271, with in-text fig. Negri et al. 2014: table 3. Huber 2015: C12478. BEDO 2017a: 48, with in-text fig. Tudu et al. 2018: table 1. Wells et al. 2021: 18.

**Referred material.** CUF-NKNY-B23 (6L+3R shells; Figs 13G, 17A).

**Habitat.** Deeply (down to 40 cm) buried in soft mud at seaward fringes of mangrove forests or intertidal zones down to 3 m depth (Huber 2015).

**Distribution.** Indian Ocean; Indo-West Pacific, from Taiwan to Borneo Island (Huber 2015). Records of fossils from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** Due to the large size and oblong-eliptical shape of shells (Robba et al. 2002; Huber 2010), we identified these specimens as belonging to *Cultellus maximus*.

**Siliqua Megerle von Mühlfeld, 1811**

**Siliqua minima (Gmelin, 1791)**

Figs 12I, 17B

*Solen minimus* Gmelin, 1791: 3227. Type locality: Tranquebar.

*Siliqua minima*. Lynge 1909: 278. Swennen et al. 2001: 47, 84, text-fig. 126, fig. 126. Robba et al. 2002: 93, pl. 12, fig. 11a, b. Robba et al. 2003: tables 3–5. Robba et al. 2007: 86 (appendix). Nabhitabhata 2009: 424. Negri et al. 2014: table 3. Yang et al. 2017: 218, fig. 822. Wells et al. 2021: 19.

*Siliqua cf. minima*. Hylleberg and Kilburn 2003: 195–196, pl. 8, fig. 10. Thach 2005: 281.

*Siliqua (Neosiliqua) minima*. Huber 2010: 273, with in-text fig. Huber 2015: C12603.
**Habitat.** Boring into submerged wood and other plant material (Poutiers 1998a).

**Taxonomic remarks and comparisons.** The calcareous burrows have a septum dividing the cavity in half, indicating that these burrows belong to the shipworm family Teredinidae (e.g., Chan and Lau 2021). Due to the absence of shells, it is impossible to assign the inhabitants to species or even genus level based on these trace fossils.

**Order Adapedonta Cossmann & Peyrot, 1909**

**Superfamily Solenoidea Lamarck, 1809**

**Family Pharidae H. Adams & A. Adams, 1856**

**Cultellus Schumacher, 1817**

**Cultellus maximus (Gmelin, 1791)**

Figs 13G, 17A

*Solen maximus* Gmelin, 1791: 3227. Type locality: Nicobar.

*Solen lacteus* Spengler, 1794: 94–95. Type locality: Nicobar.

*Cultellus lacteus*. Tantanasiriwong 1979: 11. Morris and Purchon 1981: 325. Nateewathana et al. 1981: 66. Aungtonya et al. 1999: 379. Robba et al. 2002: 92, pl. 12, fig. 10. Robba et al. 2007: 86 (appendix). Nabhitabhata 2009: 423.

*Cultellus maximus*. Subba Rao and Dey 2000: 251. Swennen et al. 2001: 47, 83, text-fig. 121, fig. 121. Huber 2010: 271, with in-text fig. Negri et al. 2014: table 3. Huber 2015: C12478. BEDO 2017a: 48, with in-text fig. Tudu et al. 2018: table 1. Wells et al. 2021: 18.

**Referred material.** CUF-NKNY-B23 (6L+3R shells; Figs 13G, 17A).

**Habitat.** Deeply (down to 40 cm) buried in soft mud at seaward fringes of mangrove forests or intertidal zones down to 3 m depth (Huber 2015).

**Distribution.** Indian Ocean; Indo-West Pacific, from Taiwan to Borneo Island (Huber 2015). Records of fossils from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Wells et al. 2021).

**Taxonomic remarks and comparisons.** Due to the large size and oblong-eliptical shape of shells (Robba et al. 2002; Huber 2010), we identified these specimens as belonging to *Cultellus maximus*.

**Siliqua Megerle von Mühlfeld, 1811**

**Siliqua minima (Gmelin, 1791)**

Figs 12I, 17B

*Solen minimus* Gmelin, 1791: 3227. Type locality: Tranquebar.

*Siliqua minima*. Lynge 1909: 278. Swennen et al. 2001: 47, 84, text-fig. 126, fig. 126. Robba et al. 2002: 93, pl. 12, fig. 11a, b. Robba et al. 2003: tables 3–5. Robba et al. 2007: 86 (appendix). Nabhitabhata 2009: 424. Negri et al. 2014: table 3. Yang et al. 2017: 218, fig. 822. Wells et al. 2021: 19.

*Siliqua cf. minima*. Hylleberg and Kilburn 2003: 195–196, pl. 8, fig. 10. Thach 2005: 281.

*Siliqua (Neosiliqua) minima*. Huber 2010: 273, with in-text fig. Huber 2015: C12603.
<figure><img src="image_17.png" /><figcaption>**Figure 17.** Bivalves and other invertebrates A *Cultellus maximus* B *Siliqua minima* C *Dentalium variabile* D *Thalassina* sp. E *Fistulobalanus kondakovi* F *Megabalanus* cf. *tintinnabulum* G *Temnotrema siamense*.</figcaption></figure>

**Referred material.** CUF-NKNY-B16 (6L+6R shells; Figs 12I, 17B).

**Habitat.** Sand and mud bottoms from intertidal zones down to 30 m depth (Huber 2015).

**Distribution.** Indian Ocean; Indo-West Pacific, from Japan to the Philippines (Robba et al. 2002; Huber 2015). Records of fossils from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Robba et al. (2002) and Huber (2010), specifically in having an ovate-rectangular and inequilateral shell with a widely rounded and deep pallial sinus, the lower border of which coincides with the pallial line, and a thin and slightly oblique inner rib.
<figure><img src="image_18.png" /><figcaption>**Figure 17.** Bivalves and other invertebrates A *Cultellus maximus* B *Siliqua minima* C *Dentalium variabile* D *Thalassina* sp. E *Fistulobalanus kondakovi* F *Megabalanus* cf. *tintinnabulum* G *Temnotrema siamense*.</figcaption></figure>

**Referred material.** CUF-NKNY-B16 (6L+6R shells; Figs 12I, 17B).

**Habitat.** Sand and mud bottoms from intertidal zones down to 30 m depth (Huber 2015).

**Distribution.** Indian Ocean; Indo-West Pacific, from Japan to the Philippines (Robba et al. 2002; Huber 2015). Records of fossils from the Holocene in Thailand (Robba et al. 2002).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Robba et al. (2002) and Huber (2010), specifically in having an ovate-rectangular and inequilateral shell with a widely rounded and deep pallial sinus, the lower border of which coincides with the pallial line, and a thin and slightly oblique inner rib.
**Class Scaphopoda** Bronn, 1862

**Order Dentaliida** Starobogatov, 1974

**Family Dentaliidae** Children, 1834

**Dentalium** Linnaeus, 1758

**Dentalium variabile** Deshayes, 1826

Figs 12H, 17C

*Dentalium variabile* Deshayes, 1826: 352–353, pl. 16, fig. 30. Type locality: possibly India. Scarabino 1995: 200–201, fig. 16d, e. Robba et al. 2003: tables 1, 3–5. Robba et al. 2004: 13, pl. 1, fig. 1. Steiner and Kabat 2004: 660. Chaiwathee et al. 2007: table 1. Robba et al. 2007: 89 (appendix). Sahlmann and Poppe 2010: 406, pl. 1198, fig. 8. Negri et al. 2014: tables 3, 4. Wells et al. 2021: 164.

*Dentalium* (*Lentigodentalium*) *variabile*. Dey and Ramakrishna 2007: 162, 257.

**Referred material.** CUF-NKNY-001 (48 shells; Figs 12H, 17C).

**Habitat.** Mud bottoms from a depth of 10–75 m (Robba et al. 2004).

**Distribution.** Indo-West Pacific, from Japan to Reunion Island and New Caledonia. Records of fossils from the Quaternary in Thailand (Robba et al. 2004).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Scarabino (1995) and Robba et al. (2004), specifically in having a polygonal cross-section of apex and a circular aperture. See also comprehensive taxonomic remarks in Scarabino (1995).

**Phylum Arthropoda**

**Subphylum Crustacea** Brünnich, 1772

**Class Malacostraca** Latreille, 1802

**Order Decapoda** Latreille, 1802

**Family Thalassinidae** Latreille, 1831

**Thalassina** Latreille, 1806

**Thalassina** sp.

Figs 13I, 17D

**Referred material.** CUF-NKNY-009 (130 pieces; Figs 13I, 17D).

**Habitat.** Littoral and sublittoral zones, mangrove swamps and forests, and edges of estuaries (Ngoc-Ho and de Saint Laurent 2009).

**Distribution.** Indo-West Pacific, from Japan to Australia (Hyžný and de Angeli 2022). Records of fossils from the Miocene to Holocene in Indo-West Pacific, and from the Oligocene in Italy (Hyžný and de Angeli 2022).

**Taxonomic remarks and comparisons.** These specimens are assigned to *Thalassina* based on descriptions in Ngoc-Ho and de Saint Laurent (2009), Sakai and Türkay (2012), and Hyžný and de Angeli (2022), specifically in having a subchelate pereiopod 1 with its propodus having dorsomedially tuberculated or spinuous carinae. There is a total of 13 species within this genus (Hyžný and de Angeli 2022), in which three species, *T. anomala* (Herbst, 1804), *T. gracilis* Dana, 1852, and *T. squamifera* De Man, 1915, are recorded from Thailand
**Class Scaphopoda** Bronn, 1862

**Order Dentaliida** Starobogatov, 1974

**Family Dentaliidae** Children, 1834

**Dentalium** Linnaeus, 1758

**Dentalium variabile** Deshayes, 1826

Figs 12H, 17C

*Dentalium variabile* Deshayes, 1826: 352–353, pl. 16, fig. 30. Type locality: possibly India. Scarabino 1995: 200–201, fig. 16d, e. Robba et al. 2003: tables 1, 3–5. Robba et al. 2004: 13, pl. 1, fig. 1. Steiner and Kabat 2004: 660. Chaiwathee et al. 2007: table 1. Robba et al. 2007: 89 (appendix). Sahlmann and Poppe 2010: 406, pl. 1198, fig. 8. Negri et al. 2014: tables 3, 4. Wells et al. 2021: 164.

*Dentalium* (*Lentigodentalium*) *variabile*. Dey and Ramakrishna 2007: 162, 257.

**Referred material.** CUF-NKNY-001 (48 shells; Figs 12H, 17C).

**Habitat.** Mud bottoms from a depth of 10–75 m (Robba et al. 2004).

**Distribution.** Indo-West Pacific, from Japan to Reunion Island and New Caledonia. Records of fossils from the Quaternary in Thailand (Robba et al. 2004).

**Record in Thailand.** Gulf of Thailand (Wells et al. 2021).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Scarabino (1995) and Robba et al. (2004), specifically in having a polygonal cross-section of apex and a circular aperture. See also comprehensive taxonomic remarks in Scarabino (1995).

**Phylum Arthropoda**

**Subphylum Crustacea** Brünnich, 1772

**Class Malacostraca** Latreille, 1802

**Order Decapoda** Latreille, 1802

**Family Thalassinidae** Latreille, 1831

**Thalassina** Latreille, 1806

**Thalassina** sp.

Figs 13I, 17D

**Referred material.** CUF-NKNY-009 (130 pieces; Figs 13I, 17D).

**Habitat.** Littoral and sublittoral zones, mangrove swamps and forests, and edges of estuaries (Ngoc-Ho and de Saint Laurent 2009).

**Distribution.** Indo-West Pacific, from Japan to Australia (Hyžný and de Angeli 2022). Records of fossils from the Miocene to Holocene in Indo-West Pacific, and from the Oligocene in Italy (Hyžný and de Angeli 2022).

**Taxonomic remarks and comparisons.** These specimens are assigned to *Thalassina* based on descriptions in Ngoc-Ho and de Saint Laurent (2009), Sakai and Türkay (2012), and Hyžný and de Angeli (2022), specifically in having a subchelate pereiopod 1 with its propodus having dorsomedially tuberculated or spinuous carinae. There is a total of 13 species within this genus (Hyžný and de Angeli 2022), in which three species, *T. anomala* (Herbst, 1804), *T. gracilis* Dana, 1852, and *T. squamifera* De Man, 1915, are recorded from Thailand
(Ngoc-Ho and de Saint Laurent 2009; Sakai and Türkay 2012) (but see the comment on the record of *T. squamifera* in Thailand in Moh et al. (2013)). However, the pereiopod 1 observed in our specimens is shorter and has a more quadrate shape. The dactylus that has a hooked tip is nearly as long as the fixed finger, suggesting an as yet unidentified species.

**Class Thecostraca Gruvel, 1905**

**Subclass Cirripedia Burmeister, 1834**

**Order Balanomorpha Pilsbry, 1916**

**Family Balanidae Leach, 1817**

**Subfamily Amphibalaninae Pitombo, 2004**

**Fistulobalanus Zullo, 1984**

**Fistulobalanus kondakovi** (Tarasov & Zevina, 1957)

Figs 12K, 17E

*Balanus amphitrite* var. *kondakovi* Tarasov & Zevina, 1957: 179, 191, fig. 76a–d.
Type locality: Japan.

*Balanus kondakovi*. Henry and Mclaughlin 1975: 114–123, text-figs 21, 22b, c, f; pl. 2, figs a–m. Yamaguchi 1977a: pl. 19, figs 6, 7; pl. 20, figs 4, 8, 12; pl. 21, fig. 4; pl. 22, figs 13–18. Yamaguchi 1977b: 176, 178, text-fig. 18. Kim and Kim 1980: 176, pl. 6, figs 1–8. Yamaguchi 1980: tables 1, 2. Jones et al. 2000: 279. Puspasari et al. 2000: tables 1, 2. Kim 2011: 119–121, fig. 64.

*Balanus amphitrite kondakovi*. Rosell 1973: 88, fig. 8a–j. Newman and Ross 1976: 63.

*Fistulobalanus kondakovi*. Zullo 1984: 1330. Pitombo 2004: 275. Prabowo and Yamaguchi 2005: table 3, fig. 3f. Chan et al. 2009: 248–251, figs 214–217. Jones and Hosie 2016: 287–288. Kepel’ 2018: 50–51, fig. 1. Kim 2020: 75–78, figs 48, 49, table 2. Karasawa and Kobayashi 2022: 71, pl. 5, fig. 10a, b.

**Referred material.** CUF-NKNY-006-1 (217 individuals; Figs 12K, 17E).

**Habitat.** Attached to hard substrates, mainly shells of oysters and gastropod molluscs and stalks of seaweed, as well as wooden piles and supports, bamboo, various objects installed under water on muddy beds for oyster culture, and buoys, in freshened closed inner parts of bays and estuarine coastal areas, from intertidal to subtidal zones (Henry and Mclaughlin 1975; Chan et al. 2009; Kepel’ 2018).

**Distribution.** Indian Ocean; Indo-West Pacific, from Japan to New Zealand (Henry and Mclaughlin 1975; Puspasari et al. 2000; Jones and Hosie 2016). Records of fossils from the Pleistocene and Holocene in Japan (Yamaguchi 1977b; Karasawa and Kobayashi 2022).

**Record in Thailand.** Gulf of Thailand (Henry and Mclaughlin 1975; Puspasari et al. 2000).

**Taxonomic remarks and comparisons.** The subfamily *Amphibalaninae* was erected to incorporate most of the species under the *Balanus amphitrite* complex/group (Pitombo 2004). Currently, there are a total of six species from this subfamily recorded from Thailand: *Amphibalanus amphitrite* (Darwin, 1854), *A. reticulatus* (Utinomi, 1967), *A. thailandicus* (Puspasari, Yamaguchi & Angsupanich, 2001), *A. variegatus* (Darwin, 1854), *Fistulobalanus kondakovi* (Tarasov
(Ngoc-Ho and de Saint Laurent 2009; Sakai and Türkay 2012) (but see the comment on the record of *T. squamifera* in Thailand in Moh et al. (2013)). However, the pereiopod 1 observed in our specimens is shorter and has a more quadrate shape. The dactylus that has a hooked tip is nearly as long as the fixed finger, suggesting an as yet unidentified species.

**Class Thecostraca Gruvel, 1905**

**Subclass Cirripedia Burmeister, 1834**

**Order Balanomorpha Pilsbry, 1916**

**Family Balanidae Leach, 1817**

**Subfamily Amphibalaninae Pitombo, 2004**

**Fistulobalanus Zullo, 1984**

**Fistulobalanus kondakovi** (Tarasov & Zevina, 1957)

Figs 12K, 17E

*Balanus amphitrite* var. *kondakovi* Tarasov & Zevina, 1957: 179, 191, fig. 76a–d.
Type locality: Japan.

*Balanus kondakovi*. Henry and Mclaughlin 1975: 114–123, text-figs 21, 22b, c, f; pl. 2, figs a–m. Yamaguchi 1977a: pl. 19, figs 6, 7; pl. 20, figs 4, 8, 12; pl. 21, fig. 4; pl. 22, figs 13–18. Yamaguchi 1977b: 176, 178, text-fig. 18. Kim and Kim 1980: 176, pl. 6, figs 1–8. Yamaguchi 1980: tables 1, 2. Jones et al. 2000: 279. Puspasari et al. 2000: tables 1, 2. Kim 2011: 119–121, fig. 64.

*Balanus amphitrite kondakovi*. Rosell 1973: 88, fig. 8a–j. Newman and Ross 1976: 63.

*Fistulobalanus kondakovi*. Zullo 1984: 1330. Pitombo 2004: 275. Prabowo and Yamaguchi 2005: table 3, fig. 3f. Chan et al. 2009: 248–251, figs 214–217. Jones and Hosie 2016: 287–288. Kepel’ 2018: 50–51, fig. 1. Kim 2020: 75–78, figs 48, 49, table 2. Karasawa and Kobayashi 2022: 71, pl. 5, fig. 10a, b.

**Referred material.** CUF-NKNY-006-1 (217 individuals; Figs 12K, 17E).

**Habitat.** Attached to hard substrates, mainly shells of oysters and gastropod molluscs and stalks of seaweed, as well as wooden piles and supports, bamboo, various objects installed under water on muddy beds for oyster culture, and buoys, in freshened closed inner parts of bays and estuarine coastal areas, from intertidal to subtidal zones (Henry and Mclaughlin 1975; Chan et al. 2009; Kepel’ 2018).

**Distribution.** Indian Ocean; Indo-West Pacific, from Japan to New Zealand (Henry and Mclaughlin 1975; Puspasari et al. 2000; Jones and Hosie 2016). Records of fossils from the Pleistocene and Holocene in Japan (Yamaguchi 1977b; Karasawa and Kobayashi 2022).

**Record in Thailand.** Gulf of Thailand (Henry and Mclaughlin 1975; Puspasari et al. 2000).

**Taxonomic remarks and comparisons.** The subfamily *Amphibalaninae* was erected to incorporate most of the species under the *Balanus amphitrite* complex/group (Pitombo 2004). Currently, there are a total of six species from this subfamily recorded from Thailand: *Amphibalanus amphitrite* (Darwin, 1854), *A. reticulatus* (Utinomi, 1967), *A. thailandicus* (Puspasari, Yamaguchi & Angsupanich, 2001), *A. variegatus* (Darwin, 1854), *Fistulobalanus kondakovi* (Tarasov
& Zevina, 1957), and *F. patelliformis* (Bruguière, 1789) (Henry and Mclaughlin 1975; Puspasari et al. 2000, 2001; Pochai et al. 2017). The presence of two or more rows of parietal tubes on shell walls assigns these specimens to the genus *Fistulobalanus* (Zullo 1984; Chan et al. 2009). We attribute these specimens to *F. kondakovi* because of the smooth outer surface of shells without any longitudinal ribs (Henry and Mclaughlin 1975; Chan et al. 2009; Kim 2011; Kepel' 2018).

**Subfamily Megabalaninae Leach, 1817**

**Megabalanus Hoek, 1913**

**Megabalanus cf. tintinnabulum (Linnaeus, 1758)**

Figs 13F, 17F

cf. *Lepas tintinnabulum* Linnaeus, 1758: 668. Type locality: Amboina, Indonesia [lectotype designation by Henry and McLaughlin (1986)].

cf. *Balanus (Megabalanus) tintinnabulum*. Pilsbry 1916: 55–57, pl. 10, fig. 1, 1e. Hiro 1939: 258, fig. 7a–b.

cf. *Balanus tintinnabulum* var. *tintinnabulum*. Oliveira 1941: 11–14, text-fig. 1, pl. 2, figs. 1, 2; pl. 4, fig. 1; pl. 5, fig. 3; pl. 8, fig. 6.

cf. *Balanus tintinnabulum*. Holthuis and Heerebout 1972: 24–31, pl. 1, fig. a–e.

cf. *Megabalanus tintinnabulum*. Newman and Ross 1976: 68. Henry and Mc-Laughlin 1986: 17–21, figs 1e, 2a, g, h, 3a–c, 5a–l. Jones et al. 2000: 282. Pit-ombo 2004: 275. Lozano-Cortés and Londoño-Cruz 2013: 466–467. Jones and Hosie 2016: 289–290. Pochai et al. 2017: 28–29, fig. 11

**Referred material.** CUF-NKNY-006-2 (2 individuals; Figs 13F, 17F).

**Habitat.** Attached on low exposed rocky shores in littoral areas, ship bottoms, and floating pontoons (Chan et al. 2009; Jones and Hosie 2016)

**Distribution.** Cosmopolitan (Jones and Hosie 2016).

**Record in Thailand.** Andaman Sea (Pochai et al. 2017). This is the first record of this species from Gulf of Thailand.

**Taxonomic remarks and comparisons.** These specimens are tentatively identified as belonging to *Megabalanus tintinnabulum* based on the descriptions and figures in Henry and McLaughlin (1986), Chan et al. (2009), and Pochai et al. (2017), specifically in having large cylindrical shells with smooth parietal surfaces and without spines.

**Phylum Echinodermata**

**Class Echinoidea Schumacher, 1817**

**Order Camarodonta Jackson, 1912**

**Family Temnopleuridae Agassiz, 1872**

**Temnotrema Agassiz, 1864**

**Temnotrema siamense (Mortensen, 1904)**

Figs 12T, 17G

*Pleurechinus siamensis* Mortensen, 1904: 79–82, pl. 1, figs 2, 7, 11, 20; pl. 2, figs 2, 9, 14, 15, 22; pl. 6, figs 16, 36; pl. 7, figs 14, 44, 53. Type locality: Koh
& Zevina, 1957), and *F. patelliformis* (Bruguière, 1789) (Henry and Mclaughlin 1975; Puspasari et al. 2000, 2001; Pochai et al. 2017). The presence of two or more rows of parietal tubes on shell walls assigns these specimens to the genus *Fistulobalanus* (Zullo 1984; Chan et al. 2009). We attribute these specimens to *F. kondakovi* because of the smooth outer surface of shells without any longitudinal ribs (Henry and Mclaughlin 1975; Chan et al. 2009; Kim 2011; Kepel' 2018).

**Subfamily Megabalaninae Leach, 1817**

**Megabalanus Hoek, 1913**

**Megabalanus cf. tintinnabulum (Linnaeus, 1758)**

Figs 13F, 17F

cf. *Lepas tintinnabulum* Linnaeus, 1758: 668. Type locality: Amboina, Indonesia [lectotype designation by Henry and McLaughlin (1986)].

cf. *Balanus (Megabalanus) tintinnabulum*. Pilsbry 1916: 55–57, pl. 10, fig. 1, 1e. Hiro 1939: 258, fig. 7a–b.

cf. *Balanus tintinnabulum* var. *tintinnabulum*. Oliveira 1941: 11–14, text-fig. 1, pl. 2, figs. 1, 2; pl. 4, fig. 1; pl. 5, fig. 3; pl. 8, fig. 6.

cf. *Balanus tintinnabulum*. Holthuis and Heerebout 1972: 24–31, pl. 1, fig. a–e.

cf. *Megabalanus tintinnabulum*. Newman and Ross 1976: 68. Henry and Mc-Laughlin 1986: 17–21, figs 1e, 2a, g, h, 3a–c, 5a–l. Jones et al. 2000: 282. Pit-ombo 2004: 275. Lozano-Cortés and Londoño-Cruz 2013: 466–467. Jones and Hosie 2016: 289–290. Pochai et al. 2017: 28–29, fig. 11

**Referred material.** CUF-NKNY-006-2 (2 individuals; Figs 13F, 17F).

**Habitat.** Attached on low exposed rocky shores in littoral areas, ship bottoms, and floating pontoons (Chan et al. 2009; Jones and Hosie 2016)

**Distribution.** Cosmopolitan (Jones and Hosie 2016).

**Record in Thailand.** Andaman Sea (Pochai et al. 2017). This is the first record of this species from Gulf of Thailand.

**Taxonomic remarks and comparisons.** These specimens are tentatively identified as belonging to *Megabalanus tintinnabulum* based on the descriptions and figures in Henry and McLaughlin (1986), Chan et al. (2009), and Pochai et al. (2017), specifically in having large cylindrical shells with smooth parietal surfaces and without spines.

**Phylum Echinodermata**

**Class Echinoidea Schumacher, 1817**

**Order Camarodonta Jackson, 1912**

**Family Temnopleuridae Agassiz, 1872**

**Temnotrema Agassiz, 1864**

**Temnotrema siamense (Mortensen, 1904)**

Figs 12T, 17G

*Pleurechinus siamensis* Mortensen, 1904: 79–82, pl. 1, figs 2, 7, 11, 20; pl. 2, figs 2, 9, 14, 15, 22; pl. 6, figs 16, 36; pl. 7, figs 14, 44, 53. Type locality: Koh
Mesan, 3–15 fathoms; Koh Chuen, 15–38 faths.; Koh Kram, 20–30 faths.; Koh Kahdat, 10 faths.

*Temnotrema siamense*. Clark 1925: 92. Mortensen 1940: 45. Mortensen and Gislén 1940: 103. Mortensen 1943: 259–262, fig. 139. Clark and Rowe 1971: 155. Price 1981: 8. Liao 1998: table 1. Lane et al. 2000: 485. Samyn 2003: table 2. Marsh and Morrison 2004: tables 1, 2, 5. Gopalakrishnan et al. 2012: 32. Filander and Griffiths 2014: 53. Schultz 2015: 258, 263–264, fig. 4.169b, c. Arachchige et al. 2017: table 3. Putchakarn 2018: 57, table 1. Arachchige et al. 2019: table 1. Köhler 2020: 9, 72–73, pl. 14, figs 11, 14. Mucharin and Sumitrakij 2022: 6, pl. 4, fig. 1.

*Temnotrema siamensis*. Putchakarn and Sonchaeng 2004: table 1.

**Referred material.** CUF-NKNY-002 (23 shells; Figs 12T, 17G).

**Habitat.** Coarse and high energy subtidal sand from a depth of 5–350 m (Price 1981; Schultz 2015).

**Distribution.** Persian Gulf and Indian Ocean; Indo-West Pacific, from South China Sea to Australia (Mortensen 1904; Price 1981; Schultz 2015; Arachchige et al. 2019).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Putchakarn and Sonchaeng 2004).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Mortensen (1904), Clark and Rowe (1971) and Schultz (2015), specifically in having deep horizontal grooves in ambulacral and interambulacral plates and in lacking a horizontal series of tubercles.

### Phylum Chordata

*Subphylum Vertebrata Lamarck, 1801*

*Class Chondrichthyes Huxley, 1880*

*Subcohort Selachimorpha Nelson, 1984*

*Superorder Galeomorphii Compagno, 1973*

*Order Carcharhiniformes Compagno, 1977*

*Family Carcharhinidae Jordan & Evermann, 1896*

*Carcharhinus Blainville, 1816*

*Carcharhinus cf. amblyrhynchoides (Whitley, 1934)*

Fig. 18A–E

cf. *Gillisqualus amblyrhynchoides* Whitley, 1934: 189–191, text-fig. 4. Type locality: Cape Bowling Green, Queensland.

cf. *Carcharhinus amblyrhynchoides*. Compagno 1984: 458–459, with in-text figs. Krajangdara et al. 2022: 49, with in-text figs.

**Referred material.** CUF-NKNY-S3-2 (Fig. 18A–E) (1 upper tooth).

**Description.** The crown of CUF-NKNY-S3-2 is triangular and erect with fine serrations and displays well-developed heels mesially and distally. Its lingual face is distinctly more convex than the labial one. Its base presents a damaged lingual face.

**Habitat.** Tropical, inshore and offshore, coastal-pelagic species, found over the continental and insular shelves (Compagno 1984).
Mesan, 3–15 fathoms; Koh Chuen, 15–38 faths.; Koh Kram, 20–30 faths.; Koh Kahdat, 10 faths.

*Temnotrema siamense*. Clark 1925: 92. Mortensen 1940: 45. Mortensen and Gislén 1940: 103. Mortensen 1943: 259–262, fig. 139. Clark and Rowe 1971: 155. Price 1981: 8. Liao 1998: table 1. Lane et al. 2000: 485. Samyn 2003: table 2. Marsh and Morrison 2004: tables 1, 2, 5. Gopalakrishnan et al. 2012: 32. Filander and Griffiths 2014: 53. Schultz 2015: 258, 263–264, fig. 4.169b, c. Arachchige et al. 2017: table 3. Putchakarn 2018: 57, table 1. Arachchige et al. 2019: table 1. Köhler 2020: 9, 72–73, pl. 14, figs 11, 14. Mucharin and Sumitrakij 2022: 6, pl. 4, fig. 1.

*Temnotrema siamensis*. Putchakarn and Sonchaeng 2004: table 1.

**Referred material.** CUF-NKNY-002 (23 shells; Figs 12T, 17G).

**Habitat.** Coarse and high energy subtidal sand from a depth of 5–350 m (Price 1981; Schultz 2015).

**Distribution.** Persian Gulf and Indian Ocean; Indo-West Pacific, from South China Sea to Australia (Mortensen 1904; Price 1981; Schultz 2015; Arachchige et al. 2019).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Putchakarn and Sonchaeng 2004).

**Taxonomic remarks and comparisons.** This species is recognised based on the descriptions and figures in Mortensen (1904), Clark and Rowe (1971) and Schultz (2015), specifically in having deep horizontal grooves in ambulacral and interambulacral plates and in lacking a horizontal series of tubercles.

### Phylum Chordata

*Subphylum Vertebrata Lamarck, 1801*

*Class Chondrichthyes Huxley, 1880*

*Subcohort Selachimorpha Nelson, 1984*

*Superorder Galeomorphii Compagno, 1973*

*Order Carcharhiniformes Compagno, 1977*

*Family Carcharhinidae Jordan & Evermann, 1896*

*Carcharhinus Blainville, 1816*

*Carcharhinus cf. amblyrhynchoides (Whitley, 1934)*

Fig. 18A–E

cf. *Gillisqualus amblyrhynchoides* Whitley, 1934: 189–191, text-fig. 4. Type locality: Cape Bowling Green, Queensland.

cf. *Carcharhinus amblyrhynchoides*. Compagno 1984: 458–459, with in-text figs. Krajangdara et al. 2022: 49, with in-text figs.

**Referred material.** CUF-NKNY-S3-2 (Fig. 18A–E) (1 upper tooth).

**Description.** The crown of CUF-NKNY-S3-2 is triangular and erect with fine serrations and displays well-developed heels mesially and distally. Its lingual face is distinctly more convex than the labial one. Its base presents a damaged lingual face.

**Habitat.** Tropical, inshore and offshore, coastal-pelagic species, found over the continental and insular shelves (Compagno 1984).
**Distribution.** Gulf of Aden and Indian Ocean; Indo-West Pacific, from south-ern China to Australia (Compagno 1984).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Compagno 1984; Krajangdara et al. 2022).

**Taxonomic remarks and comparisons.** The specimen CUF-NKNY-S3-2 rep-resents an anterior upper tooth. Several species of *Carcharhinus* have similar upper teeth in terms of morphology. Additional teeth and larger assemblag-es are needed for a more precise identification. Nevertheless, the tooth most resembles the upper teeth of *C. amblyrhynchoides* (Garrick 1982: fig. 20). Male individuals of *C. brachyurus* have somewhat similar upper teeth (Garrick 1982: fig. 51), but the mesial cutting edge of their crown is often more convex. *Carcharhinus limbatus* also shows the same characters, but the serration on the cusps at the base of the crown is much finer (Bass et al. 1973: pl. 5; Garrick 1982: fig. 18). The pattern of serration also resembles that of the lower teeth of *C. sorrah*, although in the latter, the base of the root is more concave and the heels of the crown are better developed, the teeth being longer mesio-distally than high baso-apically (Voigt and Weber 2011). Regarding the fossil record in Southeast Asia, similar teeth have been reported from the Late Miocene depos-its of Brunei in Borneo (Kocsis et al. 2019).

**Carcharhinus cf. amblyrhynchos (Bleeker, 1856)**

Fig. 18F-J

cf. *Carcharias (Prionodon) amblyrhynchos* Bleeker, 1856: 467–468. Type locali-ty: Java Sea near Solombo Island.

cf. *Carcharhinus amblyrhynchos*. Compagno 1984: 459–461, with in-text figs.
Krajangdara et al. 2022: 49, with in-text figs.

**Referred material.** CUF-NKNY-S3-10 (Fig. 18F-J) (1 upper tooth).

**Description.** The crown of CUF-NKNY-S3-10 displays a rather narrow main cusp with well-developed heels. The main cusp is regularly serrated, with an almost straight mesial edge and a distal one that is slightly concave. It is thus inclined distally. The labial side of the main cusp is nearly flat, whereas the lingual one is convex. Both the mesial and distal heels of the crown are poorly preserved and their serration pattern cannot thus be observed. The base of the root is concave and the nutritive groove on the bulged lingual face is poorly developed or heavily worn. The labial face of the root is nearly flat.

**Habitat.** Continental and insular shelves and adjacent oceanic waters (Com-pagno 1984).

**Distribution.** Indo-western to Central Pacific (Compagno 1984).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Compagno 1984; Krajangdara et al. 2022).

**Taxonomic remarks and comparisons.** The general shape of the crown, the regular serration of the main cusp, and the arched root are reminiscent of *C. amblyrhynchos* (Bass et al. 1973; Garrick 1982; Kocsis et al. 2019; Malysh-kina et al. 2023), but the poorly preserved heels of the teeth make a definite identification difficult to ascertain.
**Distribution.** Gulf of Aden and Indian Ocean; Indo-West Pacific, from south-ern China to Australia (Compagno 1984).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Compagno 1984; Krajangdara et al. 2022).

**Taxonomic remarks and comparisons.** The specimen CUF-NKNY-S3-2 rep-resents an anterior upper tooth. Several species of *Carcharhinus* have similar upper teeth in terms of morphology. Additional teeth and larger assemblag-es are needed for a more precise identification. Nevertheless, the tooth most resembles the upper teeth of *C. amblyrhynchoides* (Garrick 1982: fig. 20). Male individuals of *C. brachyurus* have somewhat similar upper teeth (Garrick 1982: fig. 51), but the mesial cutting edge of their crown is often more convex. *Carcharhinus limbatus* also shows the same characters, but the serration on the cusps at the base of the crown is much finer (Bass et al. 1973: pl. 5; Garrick 1982: fig. 18). The pattern of serration also resembles that of the lower teeth of *C. sorrah*, although in the latter, the base of the root is more concave and the heels of the crown are better developed, the teeth being longer mesio-distally than high baso-apically (Voigt and Weber 2011). Regarding the fossil record in Southeast Asia, similar teeth have been reported from the Late Miocene depos-its of Brunei in Borneo (Kocsis et al. 2019).

**Carcharhinus cf. amblyrhynchos (Bleeker, 1856)**

Fig. 18F-J

cf. *Carcharias* (*Prionodon*) *amblyrhynchos* Bleeker, 1856: 467–468. Type locali-ty: Java Sea near Solombo Island.

cf. *Carcharhinus amblyrhynchos*. Compagno 1984: 459–461, with in-text figs.
Krajangdara et al. 2022: 49, with in-text figs.

**Referred material.** CUF-NKNY-S3-10 (Fig. 18F-J) (1 upper tooth).

**Description.** The crown of CUF-NKNY-S3-10 displays a rather narrow main cusp with well-developed heels. The main cusp is regularly serrated, with an almost straight mesial edge and a distal one that is slightly concave. It is thus inclined distally. The labial side of the main cusp is nearly flat, whereas the lingual one is convex. Both the mesial and distal heels of the crown are poorly preserved and their serration pattern cannot thus be observed. The base of the root is concave and the nutritive groove on the bulged lingual face is poorly developed or heavily worn. The labial face of the root is nearly flat.

**Habitat.** Continental and insular shelves and adjacent oceanic waters (Com-pagno 1984).

**Distribution.** Indo-western to Central Pacific (Compagno 1984).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Compagno 1984; Krajangdara et al. 2022).

**Taxonomic remarks and comparisons.** The general shape of the crown, the regular serration of the main cusp, and the arched root are reminiscent of *C. amblyrhynchos* (Bass et al. 1973; Garrick 1982; Kocsis et al. 2019; Malysh-kina et al. 2023), but the poorly preserved heels of the teeth make a definite identification difficult to ascertain.
<figure><img src="image_18.png" /><figcaption>**Figure 18.** Carcharhinid shark teeth A-E *Carcharhinus* cf. *amblyrhynchoides*, specimen CUF-NKNY-S3-2 in A lingual B labial C mesial D distal and E apical views F-J *Carcharhinus* cf. *amblyrhynchos*, specimen CUF-NKNY-S3-10 in F lingual G labial H mesial I distal and J apical views.</figcaption></figure>

**Carcharhinus cf. leucas** (Valenciennes, 1839)
Fig. 19

cf. *Carcharias* (*Prionodon*) *leucas* Valenciennes in Müller & Henle, 1839: 42–43.
Type locality: Antilles.

cf. *Carcharhinus leucas*. Compagno 1984: 478–481, with in-text figs. Krajang-
dara et al. 2022: 52, with in-text figs.

**Referred material.** CUF-NKNY-Q04 (Fig. 19A-I), CUF-NKNY-SA-1 (Fig. 19J-N), CUF-NKNY-SB-3, CUF-NKNY-SC-5 (4 upper teeth).
<figure><img src="image_19.png" /><figcaption>Figure 18. Carcharhinid shark teeth A-E *Carcharhinus* cf. *amblyrhynchoides*, specimen CUF-NKNY-S3-2 in A lingual B labial C mesial D distal and E apical views F-J *Carcharhinus* cf. *amblyrhynchos*, specimen CUF-NKNY-S3-10 in F lingual G labial H mesial I distal and J apical views.</figcaption></figure>

**Carcharhinus cf. leucas** (Valenciennes, 1839)
Fig. 19

cf. *Carcharias* (*Prionodon*) *leucas* Valenciennes in Müller & Henle, 1839: 42–43.
Type locality: Antilles.

cf. *Carcharhinus leucas*. Compagno 1984: 478–481, with in-text figs. Krajang-
dara et al. 2022: 52, with in-text figs.

**Referred material.** CUF-NKNY-Q04 (Fig. 19A-I), CUF-NKNY-SA-1 (Fig. 19J-N), CUF-NKNY-SB-3, CUF-NKNY-SC-5 (4 upper teeth).
**Description.** Crowns show well-developed serrations, becoming larger and more complex in the basal part of the distal side of the crown. In labial or lingual view, the mesial side is almost straight, whereas the distal one is concave in its lower third. The outline of the base of the crown is more concave on the lingual face than on the labial one. The root is deep, slightly concave at its base, and does not display a nutritive groove in lingual view.

**Habitat.** Close inshore in reef-associated marine habitats, mostly in water less than 30 m depth (Compagno 1984; Krajangdara et al. 2022).

**Distribution.** Cosmopolitan in tropical and subtropical seas, but also reported from estuaries and rivers, tolerant of freshwater conditions (Compagno 1984).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Compagno 1984; Krajangdara et al. 2022).

**Taxonomic remarks and comparisons.** Teeth of *C. amboiensis* are very similar to those of *C. leucas* so that it is very difficult to differentiate them (Kocsis et al. 2019). As a result, ten incomplete teeth may belong either to *C. leucas* or *C. amboiensis*: CUF-NKNY-S2-1, CUF-NKNY-S3-9, CUF-NKNY-S5-1, CUF-NKNY-S5-5, CUF-NKNY-SA-6, CUF-NKNY-SB-2, CUF-NKNY-SC-10, CUF-NKNY-SD-7, CUF-NKNY-SE-3 and CUF-NKNY-SE-9.

**Carcharhinus cf. sorrah (Valenciennes, 1839)**
Fig. 20

cf. *Carcharias (Prionodon) sorrah* Valenciennes in Müller & Henle, 1839: 45–46, pl. 16. Type locality: Java.

cf. *Carcharhinus sorrah*. Compagno 1984: 500–501, with in-text figs. Krajangdara et al. 2022: 57, with in-text figs.

**Referred material.** CUF-NKNY-3.1 (Fig. 20A–G), CUF-NKNY-3.2 (Fig. 20H–N) (2 upper teeth).

**Description.** The crown is compressed labio-lingually. The labial face is slightly flatter than the lingual one. The cusp is inclined distally and presents a notch on its distal part. The serrations do not reach the apex of the main cusp and are enlarged, becoming more complex basally, especially on the distal heel. The mesial edge of the crown is almost straight in labial or lingual view. The base of the root is slightly concave in lingual or labial view. There is a well-developed groove with a nutritive foramen at the base of the root in lingual view.

**Habitat.** Coastal, shallow-water zones of the continental and insular shelves, primarily around coral reefs at intertidal zones down to 73 m depth (Compagno 1984; Krajangdara et al. 2022).

**Distribution.** Red Sea and Indian Ocean; Indo-West Pacific, from China to Australia (Compagno 1984).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Compagno 1984; Krajangdara et al. 2022).

**Taxonomic remarks and comparisons.** Some upper teeth of *C. sorrah* appear to display a mesial cutting edge slightly more convex than on our specimens, but this character is known to depend on ontogenetic stages and the position
**Description.** Crowns show well-developed serrations, becoming larger and more complex in the basal part of the distal side of the crown. In labial or lingual view, the mesial side is almost straight, whereas the distal one is concave in its lower third. The outline of the base of the crown is more concave on the lingual face than on the labial one. The root is deep, slightly concave at its base, and does not display a nutritive groove in lingual view.

**Habitat.** Close inshore in reef-associated marine habitats, mostly in water less than 30 m depth (Compagno 1984; Krajangdara et al. 2022).

**Distribution.** Cosmopolitan in tropical and subtropical seas, but also reported from estuaries and rivers, tolerant of freshwater conditions (Compagno 1984).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Compagno 1984; Krajangdara et al. 2022).

**Taxonomic remarks and comparisons.** Teeth of *C. amboiensis* are very similar to those of *C. leucas* so that it is very difficult to differentiate them (Kocsis et al. 2019). As a result, ten incomplete teeth may belong either to *C. leucas* or *C. amboiensis*: CUF-NKNY-S2-1, CUF-NKNY-S3-9, CUF-NKNY-S5-1, CUF-NKNY-S5-5, CUF-NKNY-SA-6, CUF-NKNY-SB-2, CUF-NKNY-SC-10, CUF-NKNY-SD-7, CUF-NKNY-SE-3 and CUF-NKNY-SE-9.

**Carcharhinus cf. sorrah (Valenciennes, 1839)**
Fig. 20

cf. *Carcharias (Prionodon) sorrah* Valenciennes in Müller & Henle, 1839: 45–46, pl. 16. Type locality: Java.

cf. *Carcharhinus sorrah*. Compagno 1984: 500–501, with in-text figs. Krajangdara et al. 2022: 57, with in-text figs.

**Referred material.** CUF-NKNY-3.1 (Fig. 20A–G), CUF-NKNY-3.2 (Fig. 20H–N) (2 upper teeth).

**Description.** The crown is compressed labio-lingually. The labial face is slightly flatter than the lingual one. The cusp is inclined distally and presents a notch on its distal part. The serrations do not reach the apex of the main cusp and are enlarged, becoming more complex basally, especially on the distal heel. The mesial edge of the crown is almost straight in labial or lingual view. The base of the root is slightly concave in lingual or labial view. There is a well-developed groove with a nutritive foramen at the base of the root in lingual view.

**Habitat.** Coastal, shallow-water zones of the continental and insular shelves, primarily around coral reefs at intertidal zones down to 73 m depth (Compagno 1984; Krajangdara et al. 2022).

**Distribution.** Red Sea and Indian Ocean; Indo-West Pacific, from China to Australia (Compagno 1984).

**Record in Thailand.** Gulf of Thailand and Andaman Sea (Compagno 1984; Krajangdara et al. 2022).

**Taxonomic remarks and comparisons.** Some upper teeth of *C. sorrah* appear to display a mesial cutting edge slightly more convex than on our specimens, but this character is known to depend on ontogenetic stages and the position
<figure><img src="image_19.png" /><figcaption>**Figure 19.** Carcharhinid shark teeth - *Carcharhinus cf. leucas* A-I specimen CUF-NKNY-Q04 in A lingual B labial and C-F different apical views G-I close-ups on the serrations of the distal cutting edge at the level of G distal heel and mesial cutting edge at the level of H upper part of the cusp and I heel. J-N specimen CUF-NKNY-SA-1 in J lingual K labial L mesial M distal and N apical views.</figcaption></figure>

of the teeth in the jaw (e.g., Bass et al. 1973: pl. 13; Garrick 1982: fig. 76). Ju-
veniles of *C. dussumieri* may have upper teeth with similar characteristics, but
the distal cutting edge of the main cusp is not serrated. This latter character
appears in larger specimens, but the mesial cutting edge of the main cusp be-
comes slightly concave. In addition, the distal heels and the distal root lobe
of the fossil teeth are more elongated than the upper teeth of *C. dussumieri*
(White 2012).
<figure><img src="image_20.png" /><figcaption>**Figure 19.** Carcharhinid shark teeth - *Carcharhinus cf. leucas* A-I specimen CUF-NKNY-Q04 in A lingual B labial and C-F different apical views G-I close-ups on the serrations of the distal cutting edge at the level of G distal heel and mesial cutting edge at the level of H upper part of the cusp and I heel. J-N specimen CUF-NKNY-SA-1 in J lingual K labial L mesial M distal and N apical views.</figcaption></figure>

of the teeth in the jaw (e.g., Bass et al. 1973: pl. 13; Garrick 1982: fig. 76). Ju-
veniles of *C. dussumieri* may have upper teeth with similar characteristics, but
the distal cutting edge of the main cusp is not serrated. This latter character
appears in larger specimens, but the mesial cutting edge of the main cusp be-
comes slightly concave. In addition, the distal heels and the distal root lobe
of the fossil teeth are more elongated than the upper teeth of *C. dussumieri*
(White 2012).
<figure><img src="image_20.png" /><figcaption>**Figure 20.** Carcharhinid shark teeth - *Carcharhinus* cf. *sorrah* **A-G** specimen CUF-NKNY-3.1 **A** lingual **B** apical **C** labial **D** mesial and **E** distal views **F, G** close-ups of the serration **F** on the distal heel and **G** on the middle part of the cusp mesial cutting-edge **H-N** specimen CUF-NKNY-3.2 **H** lingual **I** apical **J** labial **K** mesial and **L** distal views **M** close-up of the serration on the lower part of the mesial cutting-edge and **N** close-up of the serration between the heel and the base of the distal cutting edge.</figcaption></figure>
<figure><img src="image_21.png" /><figcaption>**Figure 20.** Carcharhinid shark teeth - *Carcharhinus* cf. *sorrah* **A-G** specimen CUF-NKNY-3.1 **A** lingual **B** apical **C** labial **D** mesial and **E** distal views **F, G** close-ups of the serration **F** on the distal heel and **G** on the middle part of the cusp mesial cutting-edge **H-N** specimen CUF-NKNY-3.2 **H** lingual **I** apical **J** labial **K** mesial and **L** distal views **M** close-up of the serration on the lower part of the mesial cutting-edge and **N** close-up of the serration between the heel and the base of the distal cutting edge.</figcaption></figure>
**Carcharhinus** spp.

Figs 21, 22

**Referred material.** CUF-NKNY-16.1 (Fig. 21A–G), CUF-NKNY-S2 (Fig. 21H–L), CUF-NKNY-S3-4, CUF-NKNY-S3-8, CUF-NKNY-S4-7 (5 lower teeth), CUF-NKNY-S1 (Fig. 22A–H), CUF-NKNY-S3-7 (two upper teeth).

**Description.** The specimens CUF-NKNY-16.1, CUF-NKNY-S3-4, CUF-NKNY-S3-8, and CUF-NKNY-S4-7 display a narrow main cusp that is inclined lingually. Their labial face is flatter than the lingual one. The serrations are well-developed in the upper two-third of the cusp. The serrations appear to be very fine on the mesial and distal heels in CUF-NKNY-16.1, CUF-NKNY-S3-4, and CUF-NKNY-S3-8, but the serrations are damaged in CUF-NKNY-S4-7. The root is well preserved only in CUF-NKNY-S3-4 and CUF-NKNY-S3-8, both of which display a slightly arched base, a moderately bulged lingual face with a nutritive foramen in its centre in CUF-NKNY-S3-4 and a faint nutritive groove in CUF-NKNY-S3-4. The specimen CUF-NKNY-S2 is asymmetric, with a mesial heel almost twice as elongated as the distal one and displays a sigmoid main cusp in labial or lingual view as well as in mesial or distal view, separated from the distal heel by a notch. The heels are serrated, but the main cusp is smooth. This tooth appears quite bulbous in mesial or distal view, being less compressed labio-lingually than the specimens described above. There is a well-developed nutritive groove on the root in lingual view, forming a basal notch in labial view.

A heavily worn tooth (CUF-NKNY-S3-7) is better attributed to an upper tooth. The lingual and distal faces of the crown are strongly damaged and a part of the distal end of the root is missing. The serration is only preserved in the middle part of the mesial cutting edge and appears to be quite regular. The root has a basal face slightly arched with a well-developed nutritive groove on its lingual face, forming a notch at the base of the root in labial view.

Another upper tooth, CUF-NKNY-S1, displays a crown with a quite coarse, irregular serration pattern nearly reaching the apex of the main cusp. The latter is bent lingually and slightly inclined distally. Its root shows a well-developed nutritive groove in lingual view, forming a notch at the base of the root in labial view. Apart from this notch, the base is almost straight.

**Taxonomic remarks and comparisons.** Lower teeth of *C. amblyrhynchos* (*C. wheeleri* in Garrick (1982): fig 51) display features similar to the specimen CUF-NKNY-16.1. They are characterised by a narrow main cusp that displays serrations ending at mid-height. Some of the lower teeth of *C. longimanus* also have these morphological patterns, though their crown is often more robust and wider at their base (Bass et al. 1973: pl. 17; Garrick 1982: fig. 70). Nevertheless, teeth very similar to the specimens CUF-NKNY-16.1, CUF-NKNY-S3-4, CUF-NKNY-S3-8, and CUF-NKNY-S4-7 from the Pliocene of Italy were attributed to *C. longimanus* (Marsili 2007).

The sigmoid crown of the specimen CUF-NKNY-S2 is reminiscent of the posterior lower teeth of *C. borneensis* and *C. tjutjot* (Voigt and Weber 2011). The dentition attributed to *C. dussumieri* by Voigt and Weber (2011) belongs in fact to *C. tjutjot* (White 2012). A sigmoid cusp, when present, is less developed in *C. sealei* and *C. sorrah* (Voigt and Weber 2011), and the distal heel is coarsely serrated in *C. coatesi* (White 2012). The morphology of the crown recalls that
**Carcharhinus** spp.

Figs 21, 22

**Referred material.** CUF-NKNY-16.1 (Fig. 21A–G), CUF-NKNY-S2 (Fig. 21H–L), CUF-NKNY-S3-4, CUF-NKNY-S3-8, CUF-NKNY-S4-7 (5 lower teeth), CUF-NKNY-S1 (Fig. 22A–H), CUF-NKNY-S3-7 (two upper teeth).

**Description.** The specimens CUF-NKNY-16.1, CUF-NKNY-S3-4, CUF-NKNY-S3-8, and CUF-NKNY-S4-7 display a narrow main cusp that is inclined lingually. Their labial face is flatter than the lingual one. The serrations are well-developed in the upper two-third of the cusp. The serrations appear to be very fine on the mesial and distal heels in CUF-NKNY-16.1, CUF-NKNY-S3-4, and CUF-NKNY-S3-8, but the serrations are damaged in CUF-NKNY-S4-7. The root is well preserved only in CUF-NKNY-S3-4 and CUF-NKNY-S3-8, both of which display a slightly arched base, a moderately bulged lingual face with a nutritive foramen in its centre in CUF-NKNY-S3-4 and a faint nutritive groove in CUF-NKNY-S3-4. The specimen CUF-NKNY-S2 is asymmetric, with a mesial heel almost twice as elongated as the distal one and displays a sigmoid main cusp in labial or lingual view as well as in mesial or distal view, separated from the distal heel by a notch. The heels are serrated, but the main cusp is smooth. This tooth appears quite bulbous in mesial or distal view, being less compressed labio-lingually than the specimens described above. There is a well-developed nutritive groove on the root in lingual view, forming a basal notch in labial view.

A heavily worn tooth (CUF-NKNY-S3-7) is better attributed to an upper tooth. The lingual and distal faces of the crown are strongly damaged and a part of the distal end of the root is missing. The serration is only preserved in the middle part of the mesial cutting edge and appears to be quite regular. The root has a basal face slightly arched with a well-developed nutritive groove on its lingual face, forming a notch at the base of the root in labial view.

Another upper tooth, CUF-NKNY-S1, displays a crown with a quite coarse, irregular serration pattern nearly reaching the apex of the main cusp. The latter is bent lingually and slightly inclined distally. Its root shows a well-developed nutritive groove in lingual view, forming a notch at the base of the root in labial view. Apart from this notch, the base is almost straight.

**Taxonomic remarks and comparisons.** Lower teeth of *C. amblyrhynchos* (*C. wheeleri* in Garrick (1982): fig 51) display features similar to the specimen CUF-NKNY-16.1. They are characterised by a narrow main cusp that displays serrations ending at mid-height. Some of the lower teeth of *C. longimanus* also have these morphological patterns, though their crown is often more robust and wider at their base (Bass et al. 1973: pl. 17; Garrick 1982: fig. 70). Nevertheless, teeth very similar to the specimens CUF-NKNY-16.1, CUF-NKNY-S3-4, CUF-NKNY-S3-8, and CUF-NKNY-S4-7 from the Pliocene of Italy were attributed to *C. longimanus* (Marsili 2007).

The sigmoid crown of the specimen CUF-NKNY-S2 is reminiscent of the posterior lower teeth of *C. borneensis* and *C. tjutjot* (Voigt and Weber 2011). The dentition attributed to *C. dussumieri* by Voigt and Weber (2011) belongs in fact to *C. tjutjot* (White 2012). A sigmoid cusp, when present, is less developed in *C. sealei* and *C. sorrah* (Voigt and Weber 2011), and the distal heel is coarsely serrated in *C. coatesi* (White 2012). The morphology of the crown recalls that
<figure><img src="image_21.png" /><figcaption>**Figure 21.** Carcharhinid shark teeth - *Carcharhinus* spp. A-G specimen CUF-NKNY-16.1 in A lingual B labial C mesial D distal and E, F apical views G close-ups of the serration on the upper part of the cusp mesial cutting edge in lingual view H-L specimen CUF-NKNY-S2 in H labial I apical J lingual K mesial and L distal views.</figcaption></figure>

of *Rhizoprionodon*, but in the latter genus, the distal heel is often more convex than in the specimen CUF-NKNY-S2 (Cappetta 2012: fig. 283; Carrillo-Briceño et al. 2015). This set of lower teeth is therefore attributed to the genus *Carcharhinus* but represents more than a single species, whereas the specimen CUF-NKNY-S3-7 is poorly preserved. Moreover, the posterior part is only preserved in the specimen CUF-NKNY-S1 and this does not allow us to reach the species-level identification.

There are 27 species of the genus *Carcharhinus* reported from the Southeast Asian region (Froese and Pauly 2024), and at least 20 taxa were recorded in Thai waters (Krajangdara et al. 2022) including all the ones mentioned above.
<figure><img src="image_22.png" /><figcaption>**Figure 21.** Carcharhinid shark teeth - *Carcharhinus* spp. A-G specimen CUF-NKNY-16.1 in A lingual B labial C mesial D distal and E, F apical views G close-ups of the serration on the upper part of the cusp mesial cutting edge in lingual view H-L specimen CUF-NKNY-S2 in H labial I apical J lingual K mesial and L distal views.</figcaption></figure>

of *Rhizoprionodon*, but in the latter genus, the distal heel is often more convex than in the specimen CUF-NKNY-S2 (Cappetta 2012: fig. 283; Carrillo-Briceño et al. 2015). This set of lower teeth is therefore attributed to the genus *Carcharhinus* but represents more than a single species, whereas the specimen CUF-NKNY-S3-7 is poorly preserved. Moreover, the posterior part is only preserved in the specimen CUF-NKNY-S1 and this does not allow us to reach the species-level identification.

There are 27 species of the genus *Carcharhinus* reported from the Southeast Asian region (Froese and Pauly 2024), and at least 20 taxa were recorded in Thai waters (Krajangdara et al. 2022) including all the ones mentioned above.
<figure><img src="image_22.png" /><figcaption>**Figure 22.** Carcharhinid shark teeth - *Carcharhinus* sp. A-H specimen CUF-NKNY-S1 in A lingual B labial C mesial D distal and E, F apical views G, H close-ups on the serration G at mid-height of the cusp mesial cutting-edge and H at the level of the distal heel and base of the cusp.</figcaption></figure>

**Glyphis Agassiz, 1843**

**Glyphis sp.**

Figs 23–28

**Referred material.** CUF-NKNY-8.2 (Fig. 23A–H), CUF-NKNY-Q03 (Fig. 24A–H), CUF-NKNY-S5-2, CUF-NKNY-S5-4, CUF-NKNY-S5-6, CUF-NKNY-S5-7, CUF-NKNY-SA-2 to 5, CUF-NKNY-SA-7, CUF-NKNY-SA-8, CUF-NKNY-SB-1, CUF-NKNY-SB-4 to 9, CUF-NKNY-SC-1, CUF-NKNY-SC-3 (Fig. 25A–E), CUF-NKNY-SC-4, CUF-NKNY-SC-6, CUF-NKNY-SC-8, CUF-NKNY-SC-9, CUF-NKNY-SD1 to 3 (Fig 25F–J), CUF-NKNY-SD6, CUF-NKNY-SD-8 to 10, CUF-NKNY-SE1 to 2, CUF-NKNY-SE-4 to 7, CUF-NKNY-SE-10 to 15, CUF-NKNY-SE-17 to 18 (46 upper teeth), CUF-NKNY-14 (Fig. 26A–H), CUF-NKNY-S1-1 to 4 (Fig. 26I–M), CUF-NKNY-S3-1 (Fig. 27A–E), CUF-NKNY-S3-5 to 6 (Fig. 27F–J), CUF-NKNY-S4-1 to 2 (Fig. 28A–E), CUF-NKNY-S4-4 to 6 (Fig. 28F–J) (13 lower teeth).

**Description.** Many teeth are poorly preserved. The crown of the upper teeth is triangular in outline, with a concavity at the base on both the mesial and distal sides in labial and lingual view, although the distal one is better marked, especially in anterior teeth (CUF-NKNY-S5-7). The serrations are quite fine and homogeneous in size along the cutting edges. The crown is strongly compressed labio-lingually and may be slightly curved lingually. When being broken, the crown displays a pulp cavity compressed labio-lingually, indicating an orthodont tooth histology (CUF-NKNY-SE-11). The base of the root is
<figure><img src="image_23.png" /><figcaption>**Figure 22.** Carcharhinid shark teeth - *Carcharhinus* sp. A-H specimen CUF-NKNY-S1 in A lingual B labial C mesial D distal and E, F apical views G, H close-ups on the serration G at mid-height of the cusp mesial cutting-edge and H at the level of the distal heel and base of the cusp.</figcaption></figure>

**Glyphis Agassiz, 1843**

**Glyphis sp.**

Figs 23–28

**Referred material.** CUF-NKNY-8.2 (Fig. 23A–H), CUF-NKNY-Q03 (Fig. 24A–H), CUF-NKNY-S5-2, CUF-NKNY-S5-4, CUF-NKNY-S5-6, CUF-NKNY-S5-7, CUF-NKNY-SA-2 to 5, CUF-NKNY-SA-7, CUF-NKNY-SA-8, CUF-NKNY-SB-1, CUF-NKNY-SB-4 to 9, CUF-NKNY-SC-1, CUF-NKNY-SC-3 (Fig. 25A–E), CUF-NKNY-SC-4, CUF-NKNY-SC-6, CUF-NKNY-SC-8, CUF-NKNY-SC-9, CUF-NKNY-SD1 to 3 (Fig 25F–J), CUF-NKNY-SD6, CUF-NKNY-SD-8 to 10, CUF-NKNY-SE1 to 2, CUF-NKNY-SE-4 to 7, CUF-NKNY-SE-10 to 15, CUF-NKNY-SE-17 to 18 (46 upper teeth), CUF-NKNY-14 (Fig. 26A–H), CUF-NKNY-S1-1 to 4 (Fig. 26I–M), CUF-NKNY-S3-1 (Fig. 27A–E), CUF-NKNY-S3-5 to 6 (Fig. 27F–J), CUF-NKNY-S4-1 to 2 (Fig. 28A–E), CUF-NKNY-S4-4 to 6 (Fig. 28F–J) (13 lower teeth).

**Description.** Many teeth are poorly preserved. The crown of the upper teeth is triangular in outline, with a concavity at the base on both the mesial and distal sides in labial and lingual view, although the distal one is better marked, especially in anterior teeth (CUF-NKNY-S5-7). The serrations are quite fine and homogeneous in size along the cutting edges. The crown is strongly compressed labio-lingually and may be slightly curved lingually. When being broken, the crown displays a pulp cavity compressed labio-lingually, indicating an orthodont tooth histology (CUF-NKNY-SE-11). The base of the root is
<figure><img src="image_23.png" /><figcaption>**Figure 23.** Carcharhinid shark teeth - *Glyphis* sp. specimen CUF-NKNY-8.2, upper lateral tooth in **A** lingual **B** labial **C** mesial **D** distal and **E** apical views **F-H** close-ups of the serration **F** at the base of the cusp mesial cutting-edge, **G** at the tip of the cusp and **H** on the distal heel.</figcaption></figure>

slightly concave in labial or lingual view. A well-developed nutritive groove and/or a nutritive foramen may be present on the lower half of the lingual side of the root.

The lower teeth may reach 40 mm in height. They are narrower and less compressed labio-lingually than the upper ones. The enameloid is smooth and the labial face of the crown is flatter than the lingual one. The main cusp is inclined lingually, sometimes with a sigmoid outline (CUF-NKNY-S4-2, CUF-NKNY-S4-5). Three different crown morphologies are noted. (1) On the specimens CUF-NKNY-S1-1, CUF-NKNY-S1-2, and CUF-NKNY-S1-4, the crown is devoid of heels and the tip of the main cusp is spearhead-shaped, the latter being regularly serrated, whereas the rest of the crown is smooth. (2) The specimens CUF-NKNY-S4-1 and CUF-NKNY-S4-4 have a narrow and upright triangular main cusp devoid of serration, showing a tiny accessory cusplet on each side of the main cusp in CUF-NKNY-S4-4 or only lingually in CUF-NKNY-S4-1. (3) On the specimens CUF-NKNY-S3-6, the main cusp is also upright, narrow, triangular in shape, and serrated on their mesial and distal edges. Well-developed heels are present on each side of the main cusp, separated from the latter by a notch. The heel is
<figure><img src="image_24.png" /><figcaption>**Figure 23.** Carcharhinid shark teeth - *Glyphis* sp. specimen CUF-NKNY-8.2, upper lateral tooth in **A** lingual **B** labial **C** mesial **D** distal and **E** apical views **F-H** close-ups of the serration **F** at the base of the cusp mesial cutting-edge, **G** at the tip of the cusp and **H** on the distal heel.</figcaption></figure>

slightly concave in labial or lingual view. A well-developed nutritive groove and/or a nutritive foramen may be present on the lower half of the lingual side of the root.

The lower teeth may reach 40 mm in height. They are narrower and less compressed labio-lingually than the upper ones. The enameloid is smooth and the labial face of the crown is flatter than the lingual one. The main cusp is inclined lingually, sometimes with a sigmoid outline (CUF-NKNY-S4-2, CUF-NKNY-S4-5). Three different crown morphologies are noted. (1) On the specimens CUF-NKNY-S1-1, CUF-NKNY-S1-2, and CUF-NKNY-S1-4, the crown is devoid of heels and the tip of the main cusp is spearhead-shaped, the latter being regularly serrated, whereas the rest of the crown is smooth. (2) The specimens CUF-NKNY-S4-1 and CUF-NKNY-S4-4 have a narrow and upright triangular main cusp devoid of serration, showing a tiny accessory cusplet on each side of the main cusp in CUF-NKNY-S4-4 or only lingually in CUF-NKNY-S4-1. (3) On the specimens CUF-NKNY-S3-6, the main cusp is also upright, narrow, triangular in shape, and serrated on their mesial and distal edges. Well-developed heels are present on each side of the main cusp, separated from the latter by a notch. The heel is
<figure><img src="image_24.png" /><figcaption>**Figure 24.** Carcharhinid shark teeth - *Glyphis* sp. specimen CUF-NKNY-Q03, upper anterior tooth in **A** lingual **B** labial **C** mesial **D** distal and **E** apical views **F**-**H** close-ups of the serration **F** at the base, **G** in the middle and **H** in the upper part of the cusp mesial cutting-edge.</figcaption></figure>

sometimes less marked on the mesial side (CUF-NKNY-S3-1). The heels display less developed serration than on the main cusp. Many teeth belonging to this morphotype display a broken apex of the main cusp (CUF-NKNY-14).

The root displays a bulged lingual face. It is more massive and more arched in spearhead-shaped teeth than in heeled ones. There is a nutritive groove in the lingual side of the root with a nutritive foramen in its middle part that can be observed in most of the teeth. The specimen CUF-NKNY-S1-1 displays a double groove.

**Taxonomic remarks and comparisons.** Upper anterior teeth (CUF-NKNY-Q03) are more erect and narrower than the lateral ones (CUF-NKNY-8.2). Lower teeth with a spearhead-shaped apex correspond to the larger teeth in our sample, in agreement with the fact that this morphology is known only in anterior teeth of adult specimens of *Glyphis glyphis* and *G. garricki*. However, lateral teeth of these species display serrated heels and teeth of juveniles can display a pair of tiny lateral cusplets (Compagno et al. 2008; White et al. 2015). As a result, the three lower tooth morphotypes described above could be encountered into
<figure><img src="image_25.png" /><figcaption>**Figure 24.** Carcharhinid shark teeth - *Glyphis* sp. specimen CUF-NKNY-Q03, upper anterior tooth in **A** lingual **B** labial **C** mesial **D** distal and **E** apical views **F**-**H** close-ups of the serration **F** at the base, **G** in the middle and **H** in the upper part of the cusp mesial cutting-edge.</figcaption></figure>

sometimes less marked on the mesial side (CUF-NKNY-S3-1). The heels display less developed serration than on the main cusp. Many teeth belonging to this morphotype display a broken apex of the main cusp (CUF-NKNY-14).

The root displays a bulged lingual face. It is more massive and more arched in spearhead-shaped teeth than in heeled ones. There is a nutritive groove in the lingual side of the root with a nutritive foramen in its middle part that can be observed in most of the teeth. The specimen CUF-NKNY-S1-1 displays a double groove.

**Taxonomic remarks and comparisons.** Upper anterior teeth (CUF-NKNY-Q03) are more erect and narrower than the lateral ones (CUF-NKNY-8.2). Lower teeth with a spearhead-shaped apex correspond to the larger teeth in our sample, in agreement with the fact that this morphology is known only in anterior teeth of adult specimens of *Glyphis glyphis* and *G. garricki*. However, lateral teeth of these species display serrated heels and teeth of juveniles can display a pair of tiny lateral cusplets (Compagno et al. 2008; White et al. 2015). As a result, the three lower tooth morphotypes described above could be encountered into
<figure><img src="image_25.png" /><figcaption>**Figure 25.** Carcharhinid shark teeth - *Glyphis* sp. A-E specimen CUF-NKNY-SC-3, upper anterolateral tooth in A lingual B labial C mesial D distal and E apical views F-J specimen CUF-NKNY-SD-3, upper lateral tooth in F lingual G labial H mesial I distal and J apical views.</figcaption></figure>

a single species during its ontogeny. Otherwise, it could indicate the presence
of more than one species, possibly three: *G. glyphis*, *G. garricki*, and *G. gan-
geticus*, as the latter species often possesses anterior lower teeth with tiny
lateral cusplets but lacks the spearhead-shaped apex (Roberts 2006; Cappetta
2012). Consequently, the teeth described above are left in open nomenclature
as *Glyphis* sp. This taxon appears to be most common in the studied fauna,
although the discrepancies between the number of upper and lower teeth re-
covered suggest some degree of collecting bias.
<figure><img src="image_26.png" /><figcaption>**Figure 25.** Carcharhinid shark teeth - *Glyphis* sp. A-E specimen CUF-NKNY-SC-3, upper anterolateral tooth in A lingual B labial C mesial D distal and E apical views F-J specimen CUF-NKNY-SD-3, upper lateral tooth in F lingual G labial H mesial I distal and J apical views.</figcaption></figure>

a single species during its ontogeny. Otherwise, it could indicate the presence
of more than one species, possibly three: *G. glyphis*, *G. garricki*, and *G. gan-
geticus*, as the latter species often possesses anterior lower teeth with tiny
lateral cusplets but lacks the spearhead-shaped apex (Roberts 2006; Cappetta
2012). Consequently, the teeth described above are left in open nomenclature
as *Glyphis* sp. This taxon appears to be most common in the studied fauna,
although the discrepancies between the number of upper and lower teeth re-
covered suggest some degree of collecting bias.
<figure><img src="image_26.png" /><figcaption>**Figure 26.** Carcharhinid shark teeth - *Glyphis* sp. A-H specimen CUF-NKNY-14, lower tooth in A lingual B labial C mesial D distal and E apical views F-H close-ups on the serration F on the distal heel, G at the base of the cusp distal cutting-edge and H in the middle part of the cusp mesial cutting-edge I-M specimen CUF-NKNY-S1-2, lower anterior tooth in I lingual J labial K mesial L distal and M apical views.</figcaption></figure>
<figure><img src="image_27.png" /><figcaption>**Figure 26.** Carcharhinid shark teeth - *Glyphis* sp. A-H specimen CUF-NKNY-14, lower tooth in A lingual B labial C mesial D distal and E apical views F-H close-ups on the serration F on the distal heel, G at the base of the cusp distal cutting-edge and H in the middle part of the cusp mesial cutting-edge I-M specimen CUF-NKNY-S1-2, lower anterior tooth in I lingual J labial K mesial L distal and M apical views.</figcaption></figure>
<figure><img src="image_27.png" /><figcaption>**Figure 27.** Carcharhinid shark teeth - *Glyphis* sp. A-E specimen CUF-NKNY-S3-1, lower tooth in A lingual B labial C mesial D distal and E apical views F-J specimen CUF-NKNY-S3-6, lower tooth in F lingual G labial H mesial I distal and J apical views.</figcaption></figure>

The genus is specific to the Indo-West Pacific tropical region and often referred as "river shark" due to its habitat in or nearby rivers and estuaries. They are quite rare, hence difficult to study. Five living species are known (Froese and Pauly 2024), but DNA analyses suggest that some of these are conspecific (Li et al. 2015). On the other hand, teeth of *Glyphis* are often recorded from Southeast Asia (Shimada et al. 2016; Kocsis et al. 2019 and references therein).

### Scoliodon Müller & Henle, 1837

### Scoliodon cf. laticaudus Müller & Henle, 1838
Fig. 29

cf. *Carcharias (Scoliodon) laticaudus* Müller & Henle, 1838: 28–29, pl. 8. Type locality: India.

cf. *Scoliodon laticaudus*. Compagno 1984: 534–535, with in-text figs. Krajangdara et al. 2022: 62, with in-text figs.
<figure><img src="image_28.png" /><figcaption>**Figure 27.** Carcharhinid shark teeth - *Glyphis* sp. A-E specimen CUF-NKNY-S3-1, lower tooth in A lingual B labial C mesial D distal and E apical views F-J specimen CUF-NKNY-S3-6, lower tooth in F lingual G labial H mesial I distal and J apical views.</figcaption></figure>

The genus is specific to the Indo-West Pacific tropical region and often referred as "river shark" due to its habitat in or nearby rivers and estuaries. They are quite rare, hence difficult to study. Five living species are known (Froese and Pauly 2024), but DNA analyses suggest that some of these are conspecific (Li et al. 2015). On the other hand, teeth of *Glyphis* are often recorded from Southeast Asia (Shimada et al. 2016; Kocsis et al. 2019 and references therein).

**Scoliodon Müller & Henle, 1837**

**Scoliodon cf. laticaudus Müller & Henle, 1838**
Fig. 29

cf. *Carcharias (Scoliodon) laticaudus* Müller & Henle, 1838: 28–29, pl. 8. Type locality: India.

cf. *Scoliodon laticaudus*. Compagno 1984: 534–535, with in-text figs. Krajangdara et al. 2022: 62, with in-text figs.
<figure><img src="image_28.png" /><figcaption>**Figure 28.** Carcharhinid shark teeth - *Glyphis* sp. A-E specimen CUF-NKNY-S4-1, lower tooth in A lingual B labial C mesial D distal and E apical views F-J specimen CUF-NKNY-S4-4, lower anterior tooth in F lingual G labial H mesial I distal and J apical views.</figcaption></figure>

**Referred material.** CUF-NKNY-S3-S5 (Fig. 29A-O) (3 teeth).

**Description.** The specimen CUF-NKNY-S3 is a small and elongated tooth with a low crown and a worn off root. The mesial cutting edge is concave and smooth and continues along the mesial heel. The distal edge of the crown is convex and separated by a notch from a distinct distal heel.
<figure><img src="image_29.png" /><figcaption>**Figure 28.** Carcharhinid shark teeth - *Glyphis* sp. A-E specimen CUF-NKNY-S4-1, lower tooth in A lingual B labial C mesial D distal and E apical views F-J specimen CUF-NKNY-S4-4, lower anterior tooth in F lingual G labial H mesial I distal and J apical views.</figcaption></figure>

**Referred material.** CUF-NKNY-S3-S5 (Fig. 29A-O) (3 teeth).

**Description.** The specimen CUF-NKNY-S3 is a small and elongated tooth with a low crown and a worn off root. The mesial cutting edge is concave and smooth and continues along the mesial heel. The distal edge of the crown is convex and separated by a notch from a distinct distal heel.
The specimen CUF-NKNY-S4 is a well-preserved tooth, with a crown strongly curved distally. The mesial cutting edge is sinusoid, starting convex, then becoming concave towards the apex. The apex of the crown overhangs distally the basal part of the tooth. The distal cutting edge is also sinusoid, though less so than the mesial one, and it is separated by a distinct notch from a well-developed distal heel. The enameloid of the crown extends more basally on the labial side of the tooth. The root is thick and the lobes run rather horizontally. It bears a well-developed and deep nutritive groove in the centre.

The cusp of the specimen CUF-NKNY-S5 is strongly sigmoid in labial and lingual view, and similar to that of CUF-NKNY-S4, but its cusp is narrower and less wide at the base, with more apparent mesial heels. The cutting edge is smooth and does not reach the apex of the cusp on its mesial side. The heels of the crown display faint serrations. The root is asymmetric and projected lingually and distally. There is a well-defined groove distally on the lingual side of the basal face, forming a deep notch in apical view.

**Habitat.** Tropical zones of continental and insular shelves close to inshore, frequently in rocky areas (Compagno 1984).

**Distribution.** Indian Ocean; Indo-West Pacific, from Japan to Indonesia (Compagno 1984).

**Record in Thailand.** Andaman Sea (Krajangdara et al. 2022).

**Taxonomic remarks and comparisons.** The three teeth best fit the dentition of the modern species *S. laticaudus* (spadenose shark). The specimen CUF-NKNY-S5 has a slender sigmoidal cusp and its mesial cutting edge does not reach the apex. It displays an asymmetric root, corresponding perfectly to a parasymphyseal tooth of a male specimen (Herman et al. 1991). The specimen CUF-NKNY-S4 likely represents an upper anterior-anterolateral tooth, whereas the specimen CUF-NKNY-S3 is probably a lower anterolateral tooth (see Springer 1964: fig. 3a). White et al. (2010) recognised another species, *S. macrorhynchos*, in the Western Pacific, meanwhile a molecular study also indicates the possible third *Scoliodon* species from the region (Lim et al. 2022), hence these fossil teeth are described in open nomenclature.

It may be mentioned that the specimen CUF-NKNY-S3 also resembles that of the lower anterolateral teeth of other common sharks in Southeast Asia (Krajangdara et al. 2022) such as *Loxodon macrorhinus* (sliteye shark) and two *Rhizoprionodon* species, *R. acutus* (milk shark) and *R. oligolinx* (grey sharpnose shark). For the teeth of *Loxodon*, the apex of the crown is higher and somewhat aligned in a more distal position than that of the specimen CUF-NKNY-S3 (Springer 1964: fig. 4; Bass et al. 1975: pl. 8). The teeth of *R. oligolinx* seem to have a less concave mesial cutting edge (Springer 1964: fig. 13), whereas for *R. acutus*, the distal heel appears less elongated and vertically higher, but a clear distinction is difficult here (Springer 1964: fig. 6; Bass et al. 1975: pl. 9).

**Carcharhinidae indet.**

**Referred material.** CUF-NKNY-S3-3, CUF-NKNY-S4-3, CUF-NKNY-S5-3, CUF-NKNY-SC-2, CUF-NKNY-SC-7, CUF-NKNY-SD-4, CUF-NKNY-SD-5, CUF-NKNY-SD-11, CUF-NKNY-SE-8, CUF-NKNY-SE-16 (10 teeth).
The specimen CUF-NKNY-S4 is a well-preserved tooth, with a crown strongly curved distally. The mesial cutting edge is sinusoid, starting convex, then becoming concave towards the apex. The apex of the crown overhangs distally the basal part of the tooth. The distal cutting edge is also sinusoid, though less so than the mesial one, and it is separated by a distinct notch from a well-developed distal heel. The enameloid of the crown extends more basally on the labial side of the tooth. The root is thick and the lobes run rather horizontally. It bears a well-developed and deep nutritive groove in the centre.

The cusp of the specimen CUF-NKNY-S5 is strongly sigmoid in labial and lingual view, and similar to that of CUF-NKNY-S4, but its cusp is narrower and less wide at the base, with more apparent mesial heels. The cutting edge is smooth and does not reach the apex of the cusp on its mesial side. The heels of the crown display faint serrations. The root is asymmetric and projected lingually and distally. There is a well-defined groove distally on the lingual side of the basal face, forming a deep notch in apical view.

**Habitat.** Tropical zones of continental and insular shelves close to inshore, frequently in rocky areas (Compagno 1984).

**Distribution.** Indian Ocean; Indo-West Pacific, from Japan to Indonesia (Compagno 1984).

**Record in Thailand.** Andaman Sea (Krajangdara et al. 2022).

**Taxonomic remarks and comparisons.** The three teeth best fit the dentition of the modern species *S. laticaudus* (spadenose shark). The specimen CUF-NKNY-S5 has a slender sigmoidal cusp and its mesial cutting edge does not reach the apex. It displays an asymmetric root, corresponding perfectly to a parasymphyseal tooth of a male specimen (Herman et al. 1991). The specimen CUF-NKNY-S4 likely represents an upper anterior-anterolateral tooth, whereas the specimen CUF-NKNY-S3 is probably a lower anterolateral tooth (see Springer 1964: fig. 3a). White et al. (2010) recognised another species, *S. macrorhynchos*, in the Western Pacific, meanwhile a molecular study also indicates the possible third *Scoliodon* species from the region (Lim et al. 2022), hence these fossil teeth are described in open nomenclature.

It may be mentioned that the specimen CUF-NKNY-S3 also resembles that of the lower anterolateral teeth of other common sharks in Southeast Asia (Krajangdara et al. 2022) such as *Loxodon macrorhinus* (sliteye shark) and two *Rhizoprionodon* species, *R. acutus* (milk shark) and *R. oligolinx* (grey sharpnose shark). For the teeth of *Loxodon*, the apex of the crown is higher and somewhat aligned in a more distal position than that of the specimen CUF-NKNY-S3 (Springer 1964: fig. 4; Bass et al. 1975: pl. 8). The teeth of *R. oligolinx* seem to have a less concave mesial cutting edge (Springer 1964: fig. 13), whereas for *R. acutus*, the distal heel appears less elongated and vertically higher, but a clear distinction is difficult here (Springer 1964: fig. 6; Bass et al. 1975: pl. 9).

**Carcharhinidae indet.**

**Referred material.** CUF-NKNY-S3-3, CUF-NKNY-S4-3, CUF-NKNY-S5-3, CUF-NKNY-SC-2, CUF-NKNY-SC-7, CUF-NKNY-SD-4, CUF-NKNY-SD-5, CUF-NKNY-SD-11, CUF-NKNY-SE-8, CUF-NKNY-SE-16 (10 teeth).
<figure><img src="image_29.png" /><figcaption>**Figure 29.** Carcharhinid shark teeth - *Scoliodon* cf. *laticaudus* A-E specimen CUF-NKNY-S3, lower anterolateral tooth in A lingual B labial C mesial D distal and E apical views F-J specimen CUF-NKNY-S4, upper anterior-anterolateral tooth in F lingual G labial H mesial I distal and J apical views K-O specimen CUF-NKNY-S5, parasymphyseal tooth in K lingual L labial M mesial N distal and O apical views.</figcaption></figure>

**Description.** These teeth are poorly preserved. The crown is generally triangular, more or less narrow, and symmetric with serration incompletely preserved. The root is broken away or does not display the details of its vascularisation pattern.
<figure><img src="image_30.png" /><figcaption>**Figure 29.** Carcharhinid shark teeth - *Scoliodon* cf. *laticaudus* A-E specimen CUF-NKNY-S3, lower anterolateral tooth in A lingual B labial C mesial D distal and E apical views F-J specimen CUF-NKNY-S4, upper anterior-anterolateral tooth in F lingual G labial H mesial I distal and J apical views K-O specimen CUF-NKNY-S5, parasymphyseal tooth in K lingual L labial M mesial N distal and O apical views.</figcaption></figure>

**Description.** These teeth are poorly preserved. The crown is generally triangular, more or less narrow, and symmetric with serration incompletely preserved. The root is broken away or does not display the details of its vascularisation pattern.
**Taxonomic remarks and comparisons.** The presence of triangular serrated crowns suggests that most of the teeth belong to upper ones of *Carcharhinus* and/or *Glyphis*, but their poor preservation does not allow a more precise identification. The specimen CUF-NKNY-SC-7 may represent a lower tooth of *C. leucas/C. amboinensis*, but without the root and the base of the crown preserved, this is impossible to ascertain.

Superorder Batomorphii Capetta, 1980

Order Myliobatiformes Compagno, 1973

Family Dasyatidae Jordan & Gilbert, 1879

Pastinachus Rüppell, 1829

Pastinachus sp.

Fig. 30

**Referred material.** CUF-NKNY-7.1 (Fig. 30A-F), CUF-NKNY-7.2 (Fig. 30G-L), CUF-NKNY-8.1 (Fig. 30M-R) (3 teeth).

**Description.** The crown is hexagonal to diamond-shaped in apical view, longer mesio-distally than labio-lingually. The crown surface is rather smooth to heavily pitted. The labial face of the crown displays a salient horizontal bulge. There is a well-developed horizontal groove in the basal part of the crown on the lingual face. The vascularisation of the teeth is holaulacorhize. There is a row of small foramina positioned under the crown on the labial face and between one and four foramina present in the groove separating the two branches of the root in basal view.

**Taxonomic remarks and comparisons.** Heavily pitted crowns probably belong to non-functional teeth (Adnet et al. 2019). Four species of cowtail rays (*Pastinachus ater*, *P. gracilicaudus*, *P. solocirostris*, and *P. stellurostris*) are known in Southeast Asia (Last et al. 2016), all of them having been recorded in Thai waters (Krajangdara et al. 2022). Regarding the nearby fossil record, teeth of *Pastinachus* were reported from India, Taiwan, and Borneo (see discussion in Kocsis et al. 2019).

Class Actinopterygii Klein, 1885

Infraclass Teleostei Müller, 1845

Order Scombriformes Rafinesque, 1810

Family Trichiuridae Rafinesque, 1810

Trichiuridae indet.

Fig. 31

**Referred material.** CUF-NKNY-2.1 (Fig. 31A-F), CUF-NKNY-2.2 (Fig. 31G-K), CUF-NKNY-18.2 (Fig. 31L-P) (3 teeth).

**Description.** Labiolingually flattened teeth seem to thin out at their mesial edge. They are covered with elongated and fine striation. This striation becomes coarser basally and distally on the more elongated specimens (specimens CUF-NKNY-2.1 and CUF-NKNY-2.2). The latter two teeth are strongly curved distally with a concave distal edge and the more completely preserved specimen CUF-NKNY-2.1 bears an apical barb. The specimen
**Taxonomic remarks and comparisons.** The presence of triangular serrated crowns suggests that most of the teeth belong to upper ones of *Carcharhinus* and/or *Glyphis*, but their poor preservation does not allow a more precise identification. The specimen CUF-NKNY-SC-7 may represent a lower tooth of *C. leucas/C. amboinensis*, but without the root and the base of the crown preserved, this is impossible to ascertain.

Superorder Batomorphii Capetta, 1980

Order Myliobatiformes Compagno, 1973

Family Dasyatidae Jordan & Gilbert, 1879

Pastinachus Rüppell, 1829

Pastinachus sp.

Fig. 30

**Referred material.** CUF-NKNY-7.1 (Fig. 30A-F), CUF-NKNY-7.2 (Fig. 30G-L), CUF-NKNY-8.1 (Fig. 30M-R) (3 teeth).

**Description.** The crown is hexagonal to diamond-shaped in apical view, longer mesio-distally than labio-lingually. The crown surface is rather smooth to heavily pitted. The labial face of the crown displays a salient horizontal bulge. There is a well-developed horizontal groove in the basal part of the crown on the lingual face. The vascularisation of the teeth is holaulacorhize. There is a row of small foramina positioned under the crown on the labial face and between one and four foramina present in the groove separating the two branches of the root in basal view.

**Taxonomic remarks and comparisons.** Heavily pitted crowns probably belong to non-functional teeth (Adnet et al. 2019). Four species of cowtail rays (*Pastinachus ater*, *P. gracilicaudus*, *P. solocirostris*, and *P. stellurostris*) are known in Southeast Asia (Last et al. 2016), all of them having been recorded in Thai waters (Krajangdara et al. 2022). Regarding the nearby fossil record, teeth of *Pastinachus* were reported from India, Taiwan, and Borneo (see discussion in Kocsis et al. 2019).

Class Actinopterygii Klein, 1885

Infraclass Teleostei Müller, 1845

Order Scombriformes Rafinesque, 1810

Family Trichiuridae Rafinesque, 1810

Trichiuridae indet.

Fig. 31

**Referred material.** CUF-NKNY-2.1 (Fig. 31A-F), CUF-NKNY-2.2 (Fig. 31G-K), CUF-NKNY-18.2 (Fig. 31L-P) (3 teeth).

**Description.** Labiolingually flattened teeth seem to thin out at their mesial edge. They are covered with elongated and fine striation. This striation becomes coarser basally and distally on the more elongated specimens (specimens CUF-NKNY-2.1 and CUF-NKNY-2.2). The latter two teeth are strongly curved distally with a concave distal edge and the more completely preserved specimen CUF-NKNY-2.1 bears an apical barb. The specimen
<figure><img src="image_30.png" /><figcaption>**Figure 30.** Dasyatid ray teeth - *Pastinachus* sp. A-F specimen CUF-NKNY-7.1 in A lingual B labial C, F profile D occlusal and E basal views G-L specimen CUF-NKNY-7.2 in G lingual H labial I, L profile J occlusal and K basal views M-R specimen CUF-NKNY-8.1 in M lingual N labial O, R profile P occlusal and Q basal views.</figcaption></figure>

CUF-NKNY-18.2 has a curved mesial margin, whereas the distal one is vertical and straight.

**Taxonomic remarks and comparisons.** The two strongly curved teeth (specimens CUF-NKNY-2.1 and CUF-NKNY-2.2) represent fang-like features
<figure><img src="image_31.png" /><figcaption>**Figure 30.** Dasyatid ray teeth - *Pastinachus* sp. A-F specimen CUF-NKNY-7.1 in A lingual B labial C, F profile D occlusal and E basal views G-L specimen CUF-NKNY-7.2 in G lingual H labial I, L profile J occlusal and K basal views M-R specimen CUF-NKNY-8.1 in M lingual N labial O, R profile P occlusal and Q basal views.</figcaption></figure>

CUF-NKNY-18.2 has a curved mesial margin, whereas the distal one is vertical and straight.

**Taxonomic remarks and comparisons.** The two strongly curved teeth (specimens CUF-NKNY-2.1 and CUF-NKNY-2.2) represent fang-like features
<figure><img src="image_31.png" /><figcaption>**Figure 31.** Trichiuridae indet. **A-F** specimen CUF-NKNY-2.1, anterior tooth in **A, B** lateral **C** anterior **D** posterior and **E** apical views **F** close-up of the tip of the tooth **G-K** specimen CUF-NKNY-2.2, anterior tooth in **G, H** lateral **I** anterior **J** posterior and **K** apical views **L-P** specimen CUF-NKNY-18.2, lateral tooth in **L, M** lateral **N** anterior **O** posterior and **P** apical views.</figcaption></figure>

from the front of the jaw, while the specimen CUF-NKNY-18.2 comes from a
rather distal position. This latter tooth resembles somewhat the lateral teeth
of *Sphyranea* (barracuda, e.g., Gottfried et al. 2017), but those are more sym-
metrical. The global species database (Fishbase: www.fishbase.org) reports
twenty-seven cutlassfishes from the wider region of South and Southeast Asia
(Froese and Pauly 2024). Two common genera, *Trichurus* and *Lepuracanthus*,
contain some species that bear such barbed fang-like teeth (Nakamura and
Parin 1993; 1998).
<figure><img src="image_32.png" /><figcaption>**Figure 31.** Trichiuridae indet. **A-F** specimen CUF-NKNY-2.1, anterior tooth in **A, B** lateral **C** anterior **D** posterior and **E** apical views **F** close-up of the tip of the tooth **G-K** specimen CUF-NKNY-2.2, anterior tooth in **G, H** lateral **I** anterior **J** posterior and **K** apical views **L-P** specimen CUF-NKNY-18.2, lateral tooth in **L, M** lateral **N** anterior **O** posterior and **P** apical views.</figcaption></figure>

from the front of the jaw, while the specimen CUF-NKNY-18.2 comes from a rather distal position. This latter tooth resembles somewhat the lateral teeth of *Sphyranea* (barracuda, e.g., Gottfried et al. 2017), but those are more symmetrical. The global species database (Fishbase: www.fishbase.org) reports twenty-seven cutlassfishes from the wider region of South and Southeast Asia (Froese and Pauly 2024). Two common genera, *Trichurus* and *Lepuracanthus*, contain some species that bear such barbed fang-like teeth (Nakamura and Parin 1993; 1998).
**Order incertae sedis in Eupercaria Betancur-R. et al., 2014**

**Family Sciaenidae Cuvier, 1829**

**Johnius Bloch, 1793**

**Johnius sp.**

Fig. 32

**Referred material.** CUF-NKNY-16.2 (Fig. 32A-D) (1 right sagitta otolith).

**Description.** Thick otolith with a smooth external surface, whereas the internal surface bears a sulcus characteristic of the genus. The ostium is shallow, vertically positioned, higher than long, and it widens ventrally. The anterior and horizontal portion of the cauda is short and shallow, then opening posteriorly into a deep caudal funnel with an external circular shape.

**Taxonomic remarks and comparisons.** Otoliths of *Johnius* are unique and have distinct characteristics that make them easily distinguishable from those of other sciaenids or teleosts (Schwarzhans 1993). There are 21 species of *Johnius* in Southeast Asia (Froese and Pauly 2024), and most of them inhabit shallow coastal waters and estuaries but some species are capable of entering rivers. They are also known from the fossil records in Japan (Ohe 1976) and Taiwan (Lin et al. 2022).

<figure><img src="image_32.png" /><figcaption>**Figure 32.** Sciaenid otolith of *Johnius* sp., specimen CUF-NKNY-16.2, right sagitta otolith in **A** inner **B** external **C** anterior and **D** posterior views.</figcaption></figure>

Discussion

Based on the survey of mid-Holocene marine faunas from the clay pit of Na-
khon Nayok Province in Thailand, many fossils of molluscs together with oth-
er invertebrates and vertebrates have been found in the Bangkok clay layer at
a depth of ~ 5-7 m below the surface. The faunal assemblages, especially
molluscs (Table 2), depict the palaeo-ecosystem of the area at that time as
corresponding to the intertidal to sublittoral zones. Some molluscan taxa, i.e.,
*Cerithidea obtusa*, *Pirenella incisa*, *Telescopium telescopium*, *Ellobium aurisju-
dae*, *Cassidula nucleus*, and *Geloina bengalensis*, also indicate that some parts
of the area corresponded to mangrove forests and intertidal mudflats. The oc-
currence of mangrove forests has previously been corroborated by evidence
of peat and pollens from the same, as well as nearby, sites (Songtham et al.
2007, 2015). In this study, several described mollusc taxa correspond to those
reported from the Lower Central Plain of Bangkok and Samut Prakan and from
the inland of Phetchaburi coasts (Somboon 1988; Somboon and Thiramongkol
**Order incertae sedis in Eupercaria Betancur-R. et al., 2014**

**Family Sciaenidae Cuvier, 1829**

**Johnius Bloch, 1793**

**Johnius sp.**

Fig. 32

**Referred material.** CUF-NKNY-16.2 (Fig. 32A-D) (1 right sagitta otolith).

**Description.** Thick otolith with a smooth external surface, whereas the internal surface bears a sulcus characteristic of the genus. The ostium is shallow, vertically positioned, higher than long, and it widens ventrally. The anterior and horizontal portion of the cauda is short and shallow, then opening posteriorly into a deep caudal funnel with an external circular shape.

**Taxonomic remarks and comparisons.** Otoliths of *Johnius* are unique and have distinct characteristics that make them easily distinguishable from those of other sciaenids or teleosts (Schwarzhans 1993). There are 21 species of *Johnius* in Southeast Asia (Froese and Pauly 2024), and most of them inhabit shallow coastal waters and estuaries but some species are capable of entering rivers. They are also known from the fossil records in Japan (Ohe 1976) and Taiwan (Lin et al. 2022).

<figure><img src="image_33.png" /><figcaption>**Figure 32.** Sciaenid otolith of *Johnius* sp., specimen CUF-NKNY-16.2, right sagitta otolith in **A** inner **B** external **C** anterior and **D** posterior views.</figcaption></figure>

Discussion

Based on the survey of mid-Holocene marine faunas from the clay pit of Na-khon Nayok Province in Thailand, many fossils of molluscs together with oth-er invertebrates and vertebrates have been found in the Bangkok clay layer at a depth of ~ 5–7 m below the surface. The faunal assemblages, especially molluscs (Table 2), depict the palaeo-ecosystem of the area at that time as corresponding to the intertidal to sublittoral zones. Some molluscan taxa, i.e., *Cerithidea obtusa*, *Pirenella incisa*, *Telescopium telescopium*, *Ellobium aurisju-dae*, *Cassidula nucleus*, and *Geloina bengalensis*, also indicate that some parts of the area corresponded to mangrove forests and intertidal mudflats. The oc-currence of mangrove forests has previously been corroborated by evidence of peat and pollens from the same, as well as nearby, sites (Songtham et al. 2007, 2015). In this study, several described mollusc taxa correspond to those reported from the Lower Central Plain of Bangkok and Samut Prakan and from the inland of Phetchaburi coasts (Somboon 1988; Somboon and Thiramongkol
1992; Robba et al. 2007; Negri 2009, 2012; Surakiatchai et al. 2018), suggesting similar paleoenvironments of these sites.

Most of the marine and mangrove shells were found at a depth of 2.2 m below the uppermost part of a marine clay layer. The carbon-14 dating analysis indicates a mid-Holocene age for this level as being approximately 5,900–5,300 cal yr BP, whereas charcoal material was found at a greater depth of 2.2–4.6 m, spanning approximately an age from 8,800 to 5,700 cal yr BP (Table 1). However, the abundance of tree trunks and carbonised woods as well as the accumulation of peat at greater depth than most shells indicate the predominance of mangrove forests, suggesting an early stage of marine incursion further inland (Songtham et al. 2007). The ages of the Bangkok Clay deposits determined by this study are also in good agreement with those retrieved by Songtham et al. (2007). This duration corresponds to the depositional stage 2 (7,000–3,000 cal yr BP), a marine transgression time proposed by Tanabe et al. (2003). During this stage, a large mud shoal was formed around Samut Prakan Province and the Chao Phraya delta prograded toward the head of the palaeo-Gulf of Ayutthaya southward (Fig. 33; Tanabe et al. 2003). However, our chronological results suggest that the area of Ongkharak, Nakhon Nayok in central Thailand was possibly an ancient coastal shoreline between 7,900 and 5,300 cal yr BP, which was located further southward compared to the palaeogeographic scheme proposed by Tanabe et al. (2003).

The vertebrate fauna is dominated by cartilaginous fishes, among which the family Carcharhinidae is most common (Table 3). The genus *Glyphis*, also known as “river shark”, is dentally most abundant in the area due to its habitat

<table><caption>**Table 2.** Molluscan species assemblages from the Bangkok Clay deposits of Ongkharak in Nakhon Nayok recovered in the present study and from other sites retrieved from previous literature (indicated by an asterisk). NA = data not available.</caption><thead><tr><th>Class</th><th>Species in this study</th><th>Lower Central Plain and Chao Phraya delta (Somboon 1988; Somboon and Thiramongkol 1992)</th><th>Lower Central Plain of Bangkok and inland of Phetchaburi coast (Robba et al. 2007; Negri 2009)</th><th>Ban Praksa, Samut Prakan (Negri 2012)</th><th>Sam Roi Yot National Park, Phetchaburi (Surakiatchai et al. 2018)</th><th>Habitat</th><th>Substrate preference</th></tr></thead><tbody><tr><td rowspan="20">Gastropoda</td><td>1. Homalopoma cf. sangarense</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand, hard</td></tr><tr><td>2. Neripteron violaceum</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Intertidal, mangrove</td><td>Mud, hard</td></tr><tr><td>3. Nerita articulata</td><td>*</td><td>–</td><td>–</td><td>–</td><td>Intertidal, mangrove</td><td>Mud, hard</td></tr><tr><td>4. Cerithidea obtusa</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Intertidal, mangrove</td><td>Mud, hard</td></tr><tr><td>5. Pirenella incisa</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Intertidal, mangrove</td><td>Mud</td></tr><tr><td>6. Telescopium telescopium</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Intertidal, mangrove</td><td>Mud</td></tr><tr><td>7. Eunaticina papilla</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Intertidal-sublittoral</td><td>Sand</td></tr><tr><td>8. Natica stellata</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand</td></tr><tr><td>9. Natica vitellus</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Intertidal-sublittoral</td><td>Sand, mud</td></tr><tr><td>10. Paratectonatica tigrina</td><td>*</td><td>*</td><td>*</td><td>*</td><td>Intertidal-sublittoral</td><td>Sand, mud</td></tr><tr><td>11. Ergaea walshi</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Intertidal-sublittoral</td><td>Hard</td></tr><tr><td>12. Bufonaria rana</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>13. Merica elegans</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>14. Scalptia scalariformis</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>15. Pseudoneptunea varicosa</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Sublittoral</td><td>NA</td></tr><tr><td>16. Brunneifusus ternatanus</td><td>*</td><td>–</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>17. Nassarius micans</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Intertidal-sublittoral</td><td>Sand</td></tr></tbody></table>
1992; Robba et al. 2007; Negri 2009, 2012; Surakiatchai et al. 2018), suggesting similar paleoenvironments of these sites.

Most of the marine and mangrove shells were found at a depth of 2.2 m below the uppermost part of a marine clay layer. The carbon-14 dating analysis indicates a mid-Holocene age for this level as being approximately 5,900–5,300 cal yr BP, whereas charcoal material was found at a greater depth of 2.2–4.6 m, spanning approximately an age from 8,800 to 5,700 cal yr BP (Table 1). However, the abundance of tree trunks and carbonised woods as well as the accumulation of peat at greater depth than most shells indicate the predominance of mangrove forests, suggesting an early stage of marine incursion further inland (Songtham et al. 2007). The ages of the Bangkok Clay deposits determined by this study are also in good agreement with those retrieved by Songtham et al. (2007). This duration corresponds to the depositional stage 2 (7,000–3,000 cal yr BP), a marine transgression time proposed by Tanabe et al. (2003). During this stage, a large mud shoal was formed around Samut Prakan Province and the Chao Phraya delta prograded toward the head of the palaeo-Gulf of Ayutthaya southward (Fig. 33; Tanabe et al. 2003). However, our chronological results suggest that the area of Ongkharak, Nakhon Nayok in central Thailand was possibly an ancient coastal shoreline between 7,900 and 5,300 cal yr BP, which was located further southward compared to the palaeogeographic scheme proposed by Tanabe et al. (2003).

The vertebrate fauna is dominated by cartilaginous fishes, among which the family Carcharhinidae is most common (Table 3). The genus *Glyphis*, also known as “river shark”, is dentally most abundant in the area due to its habitat

<table><caption>**Table 2.** Molluscan species assemblages from the Bangkok Clay deposits of Ongkharak in Nakhon Nayok recovered in the present study and from other sites retrieved from previous literature (indicated by an asterisk). NA = data not available.</caption><thead><tr><th>Class</th><th>Species in this study</th><th>Lower Central Plain and Chao Phraya delta (Somboon 1988; Somboon and Thiramongkol 1992)</th><th>Lower Central Plain of Bangkok and inland of Phetchaburi coast (Robba et al. 2007; Negri 2009)</th><th>Ban Praksa, Samut Prakan (Negri 2012)</th><th>Sam Roi Yot National Park, Phetchaburi (Surakiatchai et al. 2018)</th><th>Habitat</th><th>Substrate preference</th></tr></thead><tbody><tr><td rowspan="20">Gastropoda</td><td>1. Homalopoma cf. sangarense</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand, hard</td></tr><tr><td>2. Neripteron violaceum</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Intertidal, mangrove</td><td>Mud, hard</td></tr><tr><td>3. Nerita articulata</td><td>*</td><td>–</td><td>–</td><td>–</td><td>Intertidal, mangrove</td><td>Mud, hard</td></tr><tr><td>4. Cerithidea obtusa</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Intertidal, mangrove</td><td>Mud, hard</td></tr><tr><td>5. Pirenella incisa</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Intertidal, mangrove</td><td>Mud</td></tr><tr><td>6. Telescopium telescopium</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Intertidal, mangrove</td><td>Mud</td></tr><tr><td>7. Eunaticina papilla</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Intertidal–sublittoral</td><td>Sand</td></tr><tr><td>8. Natica stellata</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand</td></tr><tr><td>9. Natica vitellus</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Intertidal–sublittoral</td><td>Sand, mud</td></tr><tr><td>10. Paratectonatica tigrina</td><td>*</td><td>*</td><td>*</td><td>*</td><td>Intertidal–sublittoral</td><td>Sand, mud</td></tr><tr><td>11. Ergaea walshi</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Intertidal–sublittoral</td><td>Hard</td></tr><tr><td>12. Bufonaria rana</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>13. Merica elegans</td><td>–</td><td>–</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>14. Scalptia scalariformis</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>15. Pseudoneptunea varicosa</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Sublittoral</td><td>NA</td></tr><tr><td>16. Brunneifusus ternatanus</td><td>*</td><td>–</td><td>–</td><td>–</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>17. Nassarius micans</td><td>–</td><td>*</td><td>–</td><td>–</td><td>Intertidal–sublittoral</td><td>Sand</td></tr></tbody></table>
<table><thead><tr><th>Class</th><th>Species in this study</th><th>Lower Central Plain and Chao Phraya delta (Somboon 1988; Somboon and Thiramongkol 1992)</th><th>Lower Central Plain of Bangkok and inland of Phetchaburi coast (Robba et al. 2007; Negri 2009)</th><th>Ban Praksa, Samut Prakan (Negri 2012)</th><th>Sam Roi Yot National Park, Phetchaburi (Surakatchai et al. 2018)</th><th>Habitat</th><th>Substrate preference</th></tr></thead><tbody><tr><td rowspan="15">Gastropoda</td><td>18. Nassarius siquijorensis</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>19. Chicoreus capucinus</td><td>*</td><td>-</td><td>-</td><td>-</td><td>Intertidal, mangrove</td><td>Sand, mud, hard</td></tr><tr><td>20. Indothais gradata</td><td>*</td><td>-</td><td>-</td><td>-</td><td>Sublittoral</td><td>Hard</td></tr><tr><td>21. Indothais lacera</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal- sublittoral</td><td>Mud, hard</td></tr><tr><td>22. Murex trapa</td><td>*</td><td>*</td><td>-</td><td>*</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>23. Maoritomella vallata</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>NA</td></tr><tr><td>24. Pseudoetrema fortilirata</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>25. Turricula javana</td><td>*</td><td>*</td><td>-</td><td>*</td><td>Intertidal- sublittoral</td><td>Sand, mud, hard</td></tr><tr><td>26. Paradrillia melvilli</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral-upper bathyal</td><td>NA</td></tr><tr><td>27. Inquisitor vulpionis</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand</td></tr><tr><td>28. Comitas ilariae</td><td>-</td><td>-</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand</td></tr><tr><td>29. Duplicaria tricincta</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>30. Granuliterebra bathyrhaphe</td><td>-</td><td>*</td><td>*</td><td>-</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>31. Pristiterebra miranda</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>NA</td></tr><tr><td>32. Architectonica perdix</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>33. Cylichna modesta</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>34. Ellobium aurisjudae</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal, mangrove</td><td>Sand, mud, hard</td></tr><tr><td>35. Cassidula nucleus</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal, mangrove</td><td>Mud, hard</td></tr><tr><td rowspan="18">Bivalvia</td><td>1. Jupiteria puellata</td><td>-</td><td>*</td><td>*</td><td>-</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>2. Saccella mauritiana</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand, mud, hard</td></tr><tr><td>3. Anadara inaequivalvis</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Intertidal-sublittoral</td><td>Sand, mud</td></tr><tr><td>4. Anadara indica</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>5. Tegillarca granosa</td><td>*</td><td>*</td><td>-</td><td>*</td><td>Intertidal, mangrove</td><td>Mud</td></tr><tr><td>6. Tegillarca nodifera</td><td>-</td><td>-</td><td>-</td><td>-</td><td>Intertidal- sublittoral, mangrove</td><td>Sand, mud</td></tr><tr><td>7. Estellacar olivacea</td><td>*</td><td>*</td><td>-</td><td>-</td><td>Intertidal- sublittoral, mangrove</td><td>Sand, mud</td></tr><tr><td>8. Noetiella pectunculiformis</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal- sublittoral, mangrove</td><td>Sand, mud</td></tr><tr><td>9. Magallana cf. gigas</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Intertidal- sublittoral</td><td>Mud, hard</td></tr><tr><td>10. Placuna placenta</td><td>-</td><td>*</td><td>*</td><td>*</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>11. Volachlamys singaporina</td><td>-</td><td>-</td><td>-</td><td>-</td><td>Intertidal- sublittoral</td><td>Sand, mud, hard</td></tr><tr><td>12. Pegophysema bialata</td><td>-</td><td>-</td><td>-</td><td>-</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>13. Geloina bengalensis</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal, mangrove</td><td>Mud</td></tr><tr><td>14. Lutraria complanata</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>15. Standella pellucida</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal- sublittoral, mangrove</td><td>Sand, mud</td></tr><tr><td>16. Tellinides conspicuus</td><td>-</td><td>-</td><td>-</td><td>-</td><td>Sublittoral</td><td>NA</td></tr><tr><td>17. Joanniseti oblonga</td><td>*</td><td>*</td><td>-</td><td>*</td><td>Intertidal- sublittoral</td><td>Mud</td></tr><tr><td>18. Dosinia dilecta</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Sublittoral</td><td>Mud</td></tr><tr><td>19. Paratapes undulatus</td><td>*</td><td>*</td><td>*</td><td>*</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>20. Placamen lamellatum</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>21. Corbula fortisulcata</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Intertidal-sublittoral</td><td>Sand, mud, hard</td></tr><tr><td>22. Potamocorbula sp.</td><td>NA</td><td>NA</td><td>NA</td><td>NA</td><td>Intertidal</td><td>NA</td></tr><tr><td>23. Martesia striata</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal-sublittoral</td><td>Hard</td></tr><tr><td>24. Pholas orientalis</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal-sublittoral</td><td>Sand, mud, hard</td></tr><tr><td>25. Teredinidae indet.</td><td>NA</td><td>NA</td><td>NA</td><td>NA</td><td>Intertidal-sublittoral</td><td>Hard</td></tr><tr><td>26. Cultellus maximus</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal-sublittoral, mangrove</td><td>Mud</td></tr><tr><td>27. Siliqua minima</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal-sublittoral</td><td>Sand, mud</td></tr><tr><td>Scaphopoda</td><td>1. Dentalium variabile</td><td>-</td><td>*</td><td>*</td><td>-</td><td>Sublittoral</td><td>Mud</td></tr></tbody></table>
<table><thead><tr><th>Class</th><th>Species in this study</th><th>Lower Central Plain and Chao Phraya delta (Somboon 1988; Somboon and Thiramongkol 1992)</th><th>Lower Central Plain of Bangkok and inland of Phetchaburi coast (Robba et al. 2007; Negri 2009)</th><th>Ban Praksa, Samut Prakan (Negri 2012)</th><th>Sam Roi Yot National Park, Phetchaburi (Surakatchai et al. 2018)</th><th>Habitat</th><th>Substrate preference</th></tr></thead><tbody><tr><td rowspan="15">Gastropoda</td><td>18. Nassarius siquijorensis</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>19. Chicoreus capucinus</td><td>*</td><td>-</td><td>-</td><td>-</td><td>Intertidal, mangrove</td><td>Sand, mud, hard</td></tr><tr><td>20. Indothais gradata</td><td>*</td><td>-</td><td>-</td><td>-</td><td>Sublittoral</td><td>Hard</td></tr><tr><td>21. Indothais lacera</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal- sublittoral</td><td>Mud, hard</td></tr><tr><td>22. Murex trapa</td><td>*</td><td>*</td><td>-</td><td>*</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>23. Maoritomella vallata</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>NA</td></tr><tr><td>24. Pseudoetrema fortilirata</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>25. Turricula javana</td><td>*</td><td>*</td><td>-</td><td>*</td><td>Intertidal- sublittoral</td><td>Sand, mud, hard</td></tr><tr><td>26. Paradrillia melvilli</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral-upper bathyal</td><td>NA</td></tr><tr><td>27. Inquisitor vulpionis</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand</td></tr><tr><td>28. Comitas ilariae</td><td>-</td><td>-</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand</td></tr><tr><td>29. Duplicaria tricincta</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>30. Granuliterebra bathyrhaphe</td><td>-</td><td>*</td><td>*</td><td>-</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>31. Pristiterebra miranda</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>NA</td></tr><tr><td>32. Architectonica perdix</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>33. Cylichna modesta</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>34. Ellobium aurisjudae</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal, mangrove</td><td>Sand, mud, hard</td></tr><tr><td>35. Cassidula nucleus</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal, mangrove</td><td>Mud, hard</td></tr><tr><td rowspan="20">Bivalvia</td><td>1. Jupiteria puellata</td><td>-</td><td>*</td><td>*</td><td>-</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>2. Saccella mauritiana</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand, mud, hard</td></tr><tr><td>3. Anadara inaequivalvis</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Intertidal-sublittoral</td><td>Sand, mud</td></tr><tr><td>4. Anadara indica</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>5. Tegillarca granosa</td><td>*</td><td>*</td><td>-</td><td>*</td><td>Intertidal, mangrove</td><td>Mud</td></tr><tr><td>6. Tegillarca nodifera</td><td>-</td><td>-</td><td>-</td><td>-</td><td>Intertidal- sublittoral, mangrove</td><td>Sand, mud</td></tr><tr><td>7. Estellacar olivacea</td><td>*</td><td>*</td><td>-</td><td>-</td><td>Intertidal- sublittoral, mangrove</td><td>Sand, mud</td></tr><tr><td>8. Noetiella pectunculiformis</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal- sublittoral, mangrove</td><td>Sand, mud</td></tr><tr><td>9. Magallana cf. gigas</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Intertidal- sublittoral</td><td>Mud, hard</td></tr><tr><td>10. Placuna placenta</td><td>-</td><td>*</td><td>*</td><td>*</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>11. Volachlamys singaporina</td><td>-</td><td>-</td><td>-</td><td>-</td><td>Intertidal- sublittoral</td><td>Sand, mud, hard</td></tr><tr><td>12. Pegophysema bialata</td><td>-</td><td>-</td><td>-</td><td>-</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>13. Geloina bengalensis</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal, mangrove</td><td>Mud</td></tr><tr><td>14. Lutraria complanata</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Sublittoral</td><td>Sand, mud</td></tr><tr><td>15. Standella pellucida</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal- sublittoral, mangrove</td><td>Sand, mud</td></tr><tr><td>16. Tellinides conspicuus</td><td>-</td><td>-</td><td>-</td><td>-</td><td>Sublittoral</td><td>NA</td></tr><tr><td>17. Joanniseti oblonga</td><td>*</td><td>*</td><td>-</td><td>*</td><td>Intertidal- sublittoral</td><td>Mud</td></tr><tr><td>18. Dosinia dilecta</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Sublittoral</td><td>Mud</td></tr><tr><td>19. Paratapes undulatus</td><td>*</td><td>*</td><td>*</td><td>*</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>20. Placamen lamellatum</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal- sublittoral</td><td>Sand, mud</td></tr><tr><td>21. Corbula fortisulcata</td><td>-</td><td>*</td><td>-</td><td>*</td><td>Intertidal-sublittoral</td><td>Sand, mud, hard</td></tr><tr><td>22. Potamocorbula sp.</td><td>NA</td><td>NA</td><td>NA</td><td>NA</td><td>Intertidal</td><td>NA</td></tr><tr><td>23. Martesia striata</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal-sublittoral</td><td>Hard</td></tr><tr><td>24. Pholas orientalis</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal-sublittoral</td><td>Sand, mud, hard</td></tr><tr><td>25. Teredinidae indet.</td><td>NA</td><td>NA</td><td>NA</td><td>NA</td><td>Intertidal-sublittoral</td><td>Hard</td></tr><tr><td>26. Cultellus maximus</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal-sublittoral, mangrove</td><td>Mud</td></tr><tr><td>27. Siliqua minima</td><td>-</td><td>*</td><td>-</td><td>-</td><td>Intertidal-sublittoral</td><td>Sand, mud</td></tr><tr><td>Scaphopoda</td><td>1. Dentalium variabile</td><td>-</td><td>*</td><td>*</td><td>-</td><td>Sublittoral</td><td>Mud</td></tr></tbody></table>
in or nearby rivers and estuaries. It is a cryptic shark that is difficult to study, but it has been reported that these sharks also live in coastal and shallow marine regions, while the young grow up in a river habitat where the predation pressure is reduced (Li et al. 2015). The dominant presence of this taxon is indicative of the vicinity of freshwater input and/or habitats close to rivers, corresponding to the paleogeographic context of the region (Fig. 33) and the results of other studies from the Bangkok Clay (Robba et al. 2002, 2003, 2004, 2007; Songtham et al. 2007; Negri 2009, 2012). Several *Carcharhinus* species including *C. amblyrhynchoides*, *C. amblyrhinchos*, *C. leucas*, *C. amboinensis*, and *C. sorrah* were

<table><caption>**Table 3.** Fish remains recovered from the Bangkok Clay deposits of Ongkharak in Nakhon Nayok.</caption><thead><tr><th colspan="6">Class Chondrichthyes</th></tr><tr><th>Order</th><th>Family</th><th>Species</th><th>No.</th><th>Material</th></tr></thead><tbody><tr><td rowspan="9">Carcharhiniformes</td><td rowspan="9">Carcharhinidae</td><td>Carcharhinus cf. amblyrhynchoides</td><td>1</td><td>tooth</td></tr><tr><td>Carcharhinus cf. amblyrhynchos</td><td>1</td><td>tooth</td></tr><tr><td>Carcharhinus cf. leucas</td><td>4</td><td>teeth</td></tr><tr><td>Carcharhinus leucas/ Carcharhinus amboinensis</td><td>10</td><td>teeth</td></tr><tr><td>Carcharhinus cf. sorrah</td><td>2</td><td>teeth</td></tr><tr><td>Carcharhinus spp.</td><td>7</td><td>teeth</td></tr><tr><td>Glyphis sp.</td><td>59</td><td>teeth</td></tr><tr><td>Scoliodon cf. laticaudus</td><td>3</td><td>teeth</td></tr><tr><td>Carcharhinidae indet.</td><td>10</td><td>teeth</td></tr><tr><td>Myliobatiformes</td><td>Dasyatidae</td><td>Pastinachus sp.</td><td>3</td><td>teeth</td></tr><tr><th colspan="6">Class Actinopterygii</th></tr><tr><td>Scombriformes</td><td>Trichiuridae</td><td>Trichiuridae indet.</td><td>3</td><td>teeth</td></tr><tr><td>incertae sedis in Eupercaria</td><td>Sciaenidae</td><td>Johnius sp.</td><td>1</td><td>otolith</td></tr></tbody></table>

<figure><img src="image_33.png" /><figcaption>**Figure 33.** Paleogeographic maps illustrating the evolution of the Chao Phraya delta modified from Tanabe et al. (2003), during **A** 8,000–7,000 cal yr BP and **B** 7,000–6,000 cal yr BP. Red stars indicate the location of the study area.</figcaption></figure>
in or nearby rivers and estuaries. It is a cryptic shark that is difficult to study, but it has been reported that these sharks also live in coastal and shallow marine regions, while the young grow up in a river habitat where the predation pressure is reduced (Li et al. 2015). The dominant presence of this taxon is indicative of the vicinity of freshwater input and/or habitats close to rivers, corresponding to the paleogeographic context of the region (Fig. 33) and the results of other studies from the Bangkok Clay (Robba et al. 2002, 2003, 2004, 2007; Songtham et al. 2007; Negri 2009, 2012). Several *Carcharhinus* species including *C. amblyrhynchoides*, *C. amblyrhinchos*, *C. leucas*, *C. amboinensis*, and *C. sorrah* were

<table><caption>**Table 3.** Fish remains recovered from the Bangkok Clay deposits of Ongkharak in Nakhon Nayok.</caption><thead><tr><th colspan="6">Class Chondrichthyes</th></tr><tr><th>Order</th><th>Family</th><th>Species</th><th>No.</th><th>Material</th></tr></thead><tbody><tr><td rowspan="8">Carcharhiniformes</td><td rowspan="8">Carcharhinidae</td><td>Carcharhinus cf. amblyrhynchoides</td><td>1</td><td>tooth</td></tr><tr><td>Carcharhinus cf. amblyrhynchos</td><td>1</td><td>tooth</td></tr><tr><td>Carcharhinus cf. leucas</td><td>4</td><td>teeth</td></tr><tr><td>Carcharhinus leucas/ Carcharhinus amboinensis</td><td>10</td><td>teeth</td></tr><tr><td>Carcharhinus cf. sorrah</td><td>2</td><td>teeth</td></tr><tr><td>Carcharhinus spp.</td><td>7</td><td>teeth</td></tr><tr><td>Glyphis sp.</td><td>59</td><td>teeth</td></tr><tr><td>Scoliodon cf. laticaudus</td><td>3</td><td>teeth</td></tr><tr><td>Carcharhinidae indet.</td><td>10</td><td>teeth</td></tr><tr><td>Myliobatiformes</td><td>Dasyatidae</td><td>Pastinachus sp.</td><td>3</td><td>teeth</td></tr><tr><th colspan="6">Class Actinopterygii</th></tr><tr><td>Scombriformes</td><td>Trichiuridae</td><td>Trichiuridae indet.</td><td>3</td><td>teeth</td></tr><tr><td>incertae sedis in Eupercaria</td><td>Sciaenidae</td><td>Johnius sp.</td><td>1</td><td>otolith</td></tr></tbody></table>

<figure><img src="image_34.png" /><figcaption>**Figure 33.** Paleogeographic maps illustrating the evolution of the Chao Phraya delta modified from Tanabe et al. (2003), during **A** 8,000–7,000 cal yr BP and **B** 7,000–6,000 cal yr BP. Red stars indicate the location of the study area.</figcaption></figure>
also found. As the position of the teeth in the jaws cannot be ascertained, other taxa could not be ruled out based on some similarities in tooth morphology. Nevertheless, the bull shark (*C. leucas*) appears to be abundant and is also known to live in freshwater environments. Moreover, the genus *Scoliodon* present in the area is reported from brackish environments (Riede 2004). The other recovered taxa, the stingray (*Pastinachus*), cutlassfish (Trichiuridae), and the sciaenid *Johnius* are all compatible with shallow marine coastal environments, as supported by the presence of molluscan faunas, although some species are reported from brackish environments. Due to the fact that the fish remains are almost entirely represented by isolated teeth and only one single otolith has been found so far (*Johnius*), the rarity of this type of remains could be the consequence of sampling biases and/or taphonomic processes. Therefore, targeting otoliths in future studies could shed more light on the bony fish fauna of the Bangkok Clay.

## Acknowledgments

We thank the following colleagues from the Department of Biology, Faculty of Science, Chulalongkorn University: Wichase Khonsue who led us to the locality and provided information on the sites, Somsak Panha who facilitated access to collection storage and working area, Arthit Polyotha for providing SEM images, and Kittipum Chansri and Buntika A. Butcher for providing access and taking photographs with a Leica M205C stereo light microscope. We also thank FaIs Jindewha, Sutan Saehan, Jirapan Sumpaothong, and Suwijak Pata for their assistance in the field, Santi Pailoplee (Department of Geology, Faculty of Science, Chulalongkorn University) for his help in generating the map, Mana Rugbumrung (Department of Mineral Resources) for his technical assistance and supports, and Thierry Backeljau (Royal Belgian Institute of Natural Sciences, Brussels) and Bernhard Hausdorf (Leibniz Institute for the Analysis of Biodiversity Change, Hamburg) for the access to the relevant literature. We are grateful to Montri Inthasaeng who allowed us to work at the site. Finally, we thank Jürgen Kriwet and Matthias Harzhauser for their comments on the first version of this manuscript.

## Additional information

### Conflict of interest

The authors have declared that no competing interests exist.

### Ethical statement

No ethical statement was reported.

### Funding

This research was supported by the Sci-Super VII grant, Faculty of Science, Chulalongkorn University (Grant No. Sci-Super VII_64_001, to KS and CS).

### Author contributions

Conceptualization: PJ, LK, KS, CS, GC. Data curation: NN, SK, KS. Formal analysis: PJ, KS, NN, LK, SK, GC, TC. Funding acquisition: CS, KS. Investigation: CS, TC, NN, KS. Method-
also found. As the position of the teeth in the jaws cannot be ascertained, other taxa could not be ruled out based on some similarities in tooth morphology. Nevertheless, the bull shark (*C. leucas*) appears to be abundant and is also known to live in freshwater environments. Moreover, the genus *Scoliodon* present in the area is reported from brackish environments (Riede 2004). The other recovered taxa, the stingray (*Pastinachus*), cutlassfish (Trichiuridae), and the sciaenid *Johnius* are all compatible with shallow marine coastal environments, as supported by the presence of molluscan faunas, although some species are reported from brackish environments. Due to the fact that the fish remains are almost entirely represented by isolated teeth and only one single otolith has been found so far (*Johnius*), the rarity of this type of remains could be the consequence of sampling biases and/or taphonomic processes. Therefore, targeting otoliths in future studies could shed more light on the bony fish fauna of the Bangkok Clay.

## Acknowledgments

We thank the following colleagues from the Department of Biology, Faculty of Science, Chulalongkorn University: Wichase Khonsue who led us to the locality and provided information on the sites, Somsak Panha who facilitated access to collection storage and working area, Arthit Polyotha for providing SEM images, and Kittipum Chansri and Buntika A. Butcher for providing access and taking photographs with a Leica M205C stereo light microscope. We also thank FaIs Jindewha, Sutan Saehan, Jirapan Sumpaothong, and Suwijak Pata for their assistance in the field, Santi Pailoplee (Department of Geology, Faculty of Science, Chulalongkorn University) for his help in generating the map, Mana Rugbumrung (Department of Mineral Resources) for his technical assistance and supports, and Thierry Backeljau (Royal Belgian Institute of Natural Sciences, Brussels) and Bernhard Hausdorf (Leibniz Institute for the Analysis of Biodiversity Change, Hamburg) for the access to the relevant literature. We are grateful to Montri Inthasaeng who allowed us to work at the site. Finally, we thank Jürgen Kriwet and Matthias Harzhauser for their comments on the first version of this manuscript.

## Additional information

### Conflict of interest

The authors have declared that no competing interests exist.

### Ethical statement

No ethical statement was reported.

### Funding

This research was supported by the Sci-Super VII grant, Faculty of Science, Chulalongkorn University (Grant No. Sci-Super VII_64_001, to KS and CS).

### Author contributions

Conceptualization: PJ, LK, KS, CS, GC. Data curation: NN, SK, KS. Formal analysis: PJ, KS, NN, LK, SK, GC, TC. Funding acquisition: CS, KS. Investigation: CS, TC, NN, KS. Method-
ology: CS, TC, PJ, LK, GC, KS. Project administration: KS. Resources: NN, CS, KS. Validation: LK, PJ, GC, KS. Visualization: KS, LK, GC, PJ. Writing - original draft: KS, GC, PJ, LK. Writing - review and editing: PJ, LK, GC, KS.

## Author ORCIDs

Parin Jirapatrasilp https://orcid.org/0000-0002-5591-6724

Gilles Cuny https://orcid.org/0000-0001-7680-1697

László Kocsis https://orcid.org/0000-0003-4613-1850

Chirasak Sutcharit https://orcid.org/0000-0001-7670-9540

Kantapon Suraprasit https://orcid.org/0000-0002-3428-9549

## Data availability

All of the data that support the findings of this study are available in the main text.

## References

Adams A (1852) Catalogue of the species of *Nassa*, a genus of gasteropodous Mollusca belonging to the family Buccinidae, in the collection of Hugh Cuming, Esq., with the description of some new species. Proceedings of the Zoological Society of London 19: 94–114. https://doi.org/10.1111/j.1096-3642.1851.tb01137.x

Adams A (1856) Descriptions of twenty-five new species of shells from the collection of Hugh Cuming, Esq. Proceedings of the Zoological Society of London 23: 221–226. https://www.biodiversitylibrary.org/page/30748138

Adnet S, Mouana M, Charrault A-L, Essid EM, Ammar HK, Marzougui W, Merzeraud G, Tabuce R, Vianey-Liaud M, Marivaux L (2019) Teeth, fossil record and evolutionary history of the cowtail stingray *Pastinachus* Rüppell, 1829. Historical Biology 31: 1213–1222. https://doi.org/10.1080/08912963.2018.1431779

Albano PG, Steger J, Bakker PAJ, Bogi C, Bošnjak M, Guy-Haim T, Huseyinoglu MF, Lafollette PI, Lubinevsky H, Mulas M, Stockinger M, Azzarone M, Sabelli B (2021) Numerous new records of tropical non-indigenous species in the Eastern Mediterranean highlight the challenges of their recognition and identification. ZooKeys 1010: 1–95. https://doi.org/10.3897/zookeys.1010.58759

Alf A, Thach NN (2021) Some remarks on *Lenifusus*, *Brunneifusus* and *Hemifusus* and description of two new species of *Hemifusus* (Buccinoidea, Melongenidae). Conchylia 52: 95–108.

Arachchige GM, Jayakody S, Mooi R, Kroh A (2017) A review of previous studies on the Sri Lankan echinoid fauna, with an updated species list. Zootaxa 4231(2): 151–168. https://doi.org/10.11646/zootaxa.4231.2.1

Arachchige GM, Jayakody S, Mooi R, Kroh A (2019) An annotated species list of regular echinoids from Sri Lanka with notes on some rarely seen temnopleurids. Zootaxa 4571(1): 35–57. https://doi.org/10.11646/zootaxa.4571.1.3

Aubry U, Gargiulo R, Russo S (2021) Terebridae: Descriptive and Iconographic Review from 1713 to 2021. L’Informatore Piceno, Ancona, Italy, 515 pp.

Aungtonya C, Hylleberg J (1998) Check list of sublittoral molluscs, with nine new records for the Andaman Sea. Phuket Marine Biological Center Special Publication 18: 317–322.

Aungtonya C, Thaiklang N, Srisawan D (1999) Recent records of Bivalvia in the reference collection of Phuket Marine Biological Center, Thailand. Phuket Marine Biological Center Special Publication 19: 371–383.
ology: CS, TC, PJ, LK, GC, KS. Project administration: KS. Resources: NN, CS, KS. Validation: LK, PJ, GC, KS. Visualization: KS, LK, GC, PJ. Writing - original draft: KS, GC, PJ, LK. Writing - review and editing: PJ, LK, GC, KS.

## Author ORCIDs

Parin Jirapatrasilp https://orcid.org/0000-0002-5591-6724

Gilles Cuny https://orcid.org/0000-0001-7680-1697

László Kocsis https://orcid.org/0000-0003-4613-1850

Chirasak Sutcharit https://orcid.org/0000-0001-7670-9540

Kantapon Suraprasit https://orcid.org/0000-0002-3428-9549

## Data availability

All of the data that support the findings of this study are available in the main text.

## References

Adams A (1852) Catalogue of the species of *Nassa*, a genus of gasteropodous Mollusca belonging to the family Buccinidae, in the collection of Hugh Cuming, Esq., with the description of some new species. Proceedings of the Zoological Society of London 19: 94–114. https://doi.org/10.1111/j.1096-3642.1851.tb01137.x

Adams A (1856) Descriptions of twenty-five new species of shells from the collection of Hugh Cuming, Esq. Proceedings of the Zoological Society of London 23: 221–226. https://www.biodiversitylibrary.org/page/30748138

Adnet S, Mouana M, Charrault A-L, Essid EM, Ammar HK, Marzougui W, Merzeraud G, Tabuce R, Vianey-Liaud M, Marivaux L (2019) Teeth, fossil record and evolutionary history of the cowtail stingray *Pastinachus* Rüppell, 1829. Historical Biology 31: 1213–1222. https://doi.org/10.1080/08912963.2018.1431779

Albano PG, Steger J, Bakker PAJ, Bogi C, Bošnjak M, Guy-Haim T, Huseyinoglu MF, Lafollette PI, Lubinevsky H, Mulas M, Stockinger M, Azzarone M, Sabelli B (2021) Numerous new records of tropical non-indigenous species in the Eastern Mediterranean highlight the challenges of their recognition and identification. ZooKeys 1010: 1–95. https://doi.org/10.3897/zookeys.1010.58759

Alf A, Thach NN (2021) Some remarks on *Lenifusus*, *Brunneifusus* and *Hemifusus* and description of two new species of *Hemifusus* (Buccinoidea, Melongenidae). Conchylia 52: 95–108.

Arachchige GM, Jayakody S, Mooi R, Kroh A (2017) A review of previous studies on the Sri Lankan echinoid fauna, with an updated species list. Zootaxa 4231(2): 151–168. https://doi.org/10.11646/zootaxa.4231.2.1

Arachchige GM, Jayakody S, Mooi R, Kroh A (2019) An annotated species list of regular echinoids from Sri Lanka with notes on some rarely seen temnopleurids. Zootaxa 4571(1): 35–57. https://doi.org/10.11646/zootaxa.4571.1.3

Aubry U, Gargiulo R, Russo S (2021) Terebridae: Descriptive and Iconographic Review from 1713 to 2021. L’Informatore Piceno, Ancona, Italy, 515 pp.

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