Odontozona spongicola
Creators: name: Chen, Chien-Lin
name: Chan, Tin-Yam
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Stenopodidae
Odontozona
Odontozona spongicola

description: Odontozona spongicola (Alcock & Anderson, 1899)
(Figs. 1–4)
? Richardina spongicola Alcock & Anderson, 1899: 291. (Type locality: Andaman sea)
Richardina spongicola —Alcock, 1899: pl. 42, fig. 4, 4a.— Alcock, 1901: 146.— Alcock, 1902: 273.—Lo Bianco, 1903: 251.— Bouvier, 1905a: 983.— Bouvier, 1905b: 749.— Bouvier, 1908: 888.—A. Milne-Edwards & Bouvier, 1909: 264.
Odontonoza spongicola — Holthuis, 1946: 40.— Holthuis, 1955: 144, fig. 101b.— Wicksten, 1982: 134.— Goy, 1992: 2, fig. 1c.— Holthuis, 1993: 314, fig. 309.— Okuno, 2003: 178.— Saito & Fujita, 2009: 123.— Chen et al., 2016: 482.— Saito et al., 2017: 26.— Saito & Fujita, 2018: 459.
Material examined. Indonesia, southeastern Java, SJADES 2018, stn CP 23, 6 o 46.739’S, 105 o 9.239’E, 27 Mar 2018, 559– 571 m, 1 female cl 4.2 mm (MZB).
South China Sea, Pratas, DONGSHA 2014, stn CP4127, 20 o 48.032’N, 116 o 7.996’E, 1 May 2014, 392– 408 m, 1 female cl 7.8 mm (NTOU M01910).
Description. Body laterally compressed. Rostrum (Figs. 2A, 3F) 0.36 carapace length, compressed, directed straight-forward, reaching distal margin of first segment of antennular peduncle; dorsal margin armed with 11–12 teeth, including 2–3 teeth situated posterior to orbital margin; ventral margin armed with 2–3 teeth distally; ventrolateral ridge sharp, unarmed, merging into the orbital margin.
Carapace (Figs. 2A, B) swollen, ventral and posterior margin rounded; postostral median carina low, extending to epigastric region but not reaching cervical groove; orbital margin concave; antennal lobe rounded, armed with 1 large, submarginal antennal spine; hepatic spine strong; pterygostomial angle rounded, slightly exceeding antennal spine, armed with 8–9 small pterygostomial spines; cervical groove prominent, deep, posterior margin with cincture of 23–26 acute, depressed spines, medial spines smaller than lateral spines; supraorbital region bearing numerous spines and forming a short row surrounding base of rostrum, lateral spines larger than medial spines; other parts of carapace smooth.
Eyes (Figs. 2A, B) well developed; cornea shorter and narrower than peduncle, completely absence of pigment; mesial and anterodorsal surfaces of eyestalk armed with numerous acute spinules, some aligned in rows along posterior margin of cornea.
Antennular peduncle (Figs. 2A, B) reaching two-thirds length of antennal scale. First (basal) segment longest, subequal to distal 2 segments combined; stylocerite small, acute, curved inwards; second segment with 1 or 2 dorsolateral and 1 ventromesial spine; third segment shortest, unarmed; flagella slender, long.
Antenna (Figs. 2A, B) with scaphocerite 2.5–2.7 times longer than board. Scaphocerite falciform; bearing 4–5 teeth on lateral margin, terminal tooth slightly overreaching tip of scaphocerite; dorsal surface with 2 distinct longitudinal carinae; mesial margin strongly convex.
Epistome (Figs. 3A) anteriorly with 6 sharp, slightly curved spines; labrum trilobed and rounded on anterior margin, posterior margin bilobed and rounded; paragnath with median fissure.
Mandible (Figs. 3B, C) stout, with robust palm composed of 3 articles, distal segment oval and densely setose, intermediate segment stout, proximal segment short; incisor and molar processes clearly separate, margin of incisor with 2 large blunt teeth, margin of molar armed with 5 small acute teeth.
Maxillule (Figs. 3D) robust, endopod slender and tapering distally; coxal endite broad, with row of setae on distal margin; basial endite moderate broad, truncated distally, with row of numerous slender spines.
Maxilla (Figs. 3E) with sturdy, slender endopod; coxal endite oval; basial endite oblong, both coxal and basial endites distinctly bilobed; scaphognathite well developed, anterior lobe rather large and rectangular shape, with dense long setae along inner margin, posterior lobe rounded and widened distally, inner margin with rows of setae.
Branchial formula see Table 1.
First maxilliped (Figs. 3F) with stout endopod consisting of 2 articles, distal article tapering with long setae, proximal article subquadrate; coxal endites distinctly bilobed; basial endite very large and oval, inner margin slightly convex; exopod well developed, slender; epipod rather large and distinctly bilobed, anterior lobe moderately oval and curved, posterior lobe similar to anterior lobe.
Second maxilliped (Figs. 3G) with 4-jointed robust endopod; dactylus suboval, with dense fringe of setae along distodorsal margin; propodus equal length as dactylus, with dense short setae on dorsal margin; carpus short, cuplike, with long setae on dorsal margin; merus robust and longest, about 3 times as long as propodus, with ventral margin convex; ischium, basis and coxa incompletely fused; exopod long and slender.
Third maxilliped (Figs. 3H) pediform, setose, with moderately robust endopod; dactylus and propodus subequal; propodus with apparently setiferous organs at distomesial angle; carpus slightly longer than propodus and with dense long setae; merus longest, about 1.5 times as long as propodus, dorsal margin with 4–5 spines, ventral margin with 4–6 spinules; ischium 0.9 time as long as merus; exopod long and slender, distally bearing few long setae.
First 3 pereiopods chelate, increasing in size posteriorly. First pereiopod (Fig. 4A, B) slender, thin, overreaching scaphocerite by length of chela, with well-developed grooming apparatus; fingers elongate, with hooked crossing tips, bearing tufts of long setae distally; dactylus about 0.4 time propodal length; carpus longest, about 1.3 times as long as propodus; merus 0.8–0.9 time length of carpus; ischium 0.6–0.7 time length of merus.
Second pereiopod (Fig. 4C) similar to first pereiopod, but longer (1.5 times) and lacking grooming apparatus; dactylus 0.4 time length of propodus, lateral margin with a few granules and bearing tufts of long setae distally; lateral margin of propodus with a few tubercles near midlength, with distal tufts of setae; carpus longest and 1.8 times as long as propodus; merus 0.7 time length of carpus; ischium 0.6 time of meral length.
Third pereiopod (Fig. 4D, E) largest and strongest, extending beyond scaphocerite by chela and half length of carpus; fingers slightly compressed with sharp hooked crossing tips; dactylus about 0.4 time chela length, bearing tufts of long setae distally; cutting edge of dactylus crested, with small triangular tooth proximally; cutting edge of fixed finger also crested, proximal portion with 2 blunt, truncated teeth separated by deep hiatus; palm, 2.7–3.1 times longer than wide, dorsal margin slightly convex, smooth or with 4 tubercles distally, ventral margin also gently convex, with 2–4 tubercles around midlength otherwise smooth; lateral and mesial surface glabrous, without armature; carpus about half length of chela, dorsal margin with 2 or 3 acuminate, forwardly curved spines, ventral margin with 1 spine near midlength; merus more or less as long as carpus, bearing 2 curved, acute spines on dorsal margin, 3 smaller spines on ventral margin; ischium 0.6 times length of carpus, unarmed.
Fourth and fifth pereiopods (Fig. 4F, G) slender and similar, dactyli distinctly biunguiculate. Fourth and fifth pereiopods overreaching scaphocerite by half carpus and one-third carpus, respectively; dactylus about 0.4 times length of propodus; propodus about half length of carpus, subdivided into 2 articles, ventral margin with row of 8–10 movable spines; carpus longest, subdivided in 3 distinct articles, sometimes with 1 movable spine on ventral margin of article, with 1 long seta and sometimes also 1 movable spine at ventrodistal angle; merus 0.8–0.9 time of carpal length; ischium about half length of merus, unarmed.
Abdomen (Fig. 2C) glabrous. First somite with distinct transverse carina, its margin overhanging depressed articulate part; articulate part of pleuron smooth and ventrally rounded; non-articulate part of pleuron unarmed and also ventrally rounded. Second somite with relatively low transverse carina, its margin slightly overhanging articulate part. Second to fifth pleura unarmed on lateral surfaces, ventral margin more or less rounded. Sixth somite widened posteriorly, devoid of lateral spines.
First pleopod (Fig. 2E) uniramous, shorter than other pleopods. Second to fifth pleopods biramous. Second pleopod (Fig. 2F) with protopod slightly shorter than both rami, unarmed.
Telson (Fig. 2D) lancelolate, 2 times longer than board, with median groove flanked by 2 longitudinal carinae, outer margins of carinae each bearing 6–7 strong spines, distal spine overlapping rounded posterior margin of telson, inner margin of right carina with 2 smaller spines at anterior half; basal region also bearing 2 pairs of spines; lateral margin with shallow subproximal concavity, and 1 distinct medial spine. Uropods (Fig. 2D) well developed and size similar to telson; exopod with outer margin bearing 8 small, acute teeth; dorsal surface with 2 unarmed longitudinal carinae, posterior margin rounded; endopod with outer margin smooth and posterior margin rounded, dorsal surface bearing 1 distinct straight longitudinal median ridge and 1 weak inner curved ridge, both ridges unarmed.
Coloration. Body and appendages generally whitish semitransparent. Rostrum transparent. Carapace whitish transparent, with red patch on postorbital area. Eye with cornea yellowish and posterior margin reddish. First to sixth abdominal tergites each with light red thick transverse band posteriorly, those on second and third somites largest. Mouth parts more or less reddish. Tail fan generally transparent, only with patches of light red at posterior part of lateral margins of uropods.
Distribution. Indo-Pacific and known from India, Andaman Sea, Pratas in the South China Sea, the Philippines, Indonesia, Australia and off California in the East Pacific; at depths of 392–900 m and associated with hexactinellid sponges.
Remarks. Odontozona spongicola was previously only known by eight specimens. Other than three specimens from the Philippines (Saito et al., 2017; Saito & Fujita, 2018), only one specimen has been reported from India (Alcock 1901), Andaman Sea (Alcock & Anderson 1899; Alcock 1901), Pratas (Chen et al., 2016), Australia (Goy, 1992) and California (Wicksten 1982). The present Indonesia and South China Sea specimens fit well with the characteristics of O. spongicola in the carapace swollen with posterior half behind the spinous cervical groove smooth, abdomen not sculptured, and the carpus and propodus of last two pereiopods subdivided into 2–3 distinct articles (see Alcock & Anderson 1899; Goy 1992; Saito et al. 2017). There are some discrepancies between the present material and the type from the Andaman Sea (Alcock & Anderson, 1899; Alcock, 1899, 1901). The third pereiopod has the merus bearing spines and the ventral margin of the chela having 2 to 4 tubercles in the present material but these regions are all unarmed in the type. Moreover, the ventral margins of the propodi of the last two pereiopods are spinous in the present material but also unarmed in the type. The type has two hepatic spine but the present material has only one hepatic spine. Moreover, the spines behind the cervical groove in the type (Alcock, 1899: pl.17-fig. 4) appear to be larger than those of the present material (Fig. 2A, B). Examination of the type or topotypic material is necessary to determine if these spines and tubercles are indeed absent or difference in size in specimens from the Andaman Sea and India.
On the other hand, the O. spongicola specimens from Australia and California are similar to the present material from Indonesia and the South China Sea in the merus of the third pereiopod and the propodi of the last two pereiopods being spinous (see Goy, 1992). The specimen from the South China Sea (NTOU M01910) listed in Chen et al. (2016) has the distal part of the rostrum, both second pereiopods, right third pereiopod, sixth abdominal somite and tail fan missing. This damaged South China Sea specimen, however, is generally very similar to the SJADES specimen both in morphology and coloration. For the three Philippines specimens of O. spongicola reported by in Saito et al. (2017) and Saito & Fujita (2018), no detailed description was provided.
Besides O. spongicola, there are eight other deep-water species in the genus Odontozona, viz. O. edwardsi (Bouvier, 1908), O. foresti Hendrickx, 2002, O. joegoyi Hendrick & Ayon-Parente, 2014, O. lopheliae Goy & Cardoso, 2014. O. meloi Anker & Tavares, 2013, O. minoica Dounas & Koukouras, 1989, O. spinosissima Kensley, 1981 and O. striata Goy, 1981. Among these nine species, they can be clearly subdivided into three groups. The first group has grooved and toothed abdomen, and the carapace is densely covered with many small spines (O. spinosissima and O. striata). The abdomen of the second group is smoother, and there are fewer spines on the carapace, but has two distinct rows of circular spines behind the cervical groove (O. foresti, O. meloi and O. minoica). The third group has a rather smooth abdomen, bears fewest spines on the carapace and has only one row of circular spines behind the cervical groove (O. edwardsi, O. joegoyi, O. lopheliae and O. spongicola). Among the four species in the third group, O. spongicola differs from O. joegoyi in bearing hepatic spines (vs. absent) and the abdomen pleura ventrally smooth (vs. spinulose). The present species mainly differs from O. lopheliae in the third pereiopod, which is much more spinose in the propodus to carpus for O. lopheliae. Odontozona edwardsi differs from O. spongicola in lacking the transverse grooves on the anterior three abdominal somites but bearing dorso-transverse carina on the sixth abdominal somite, and propodus of the third pereopod distinctly spinous. It may need to point out that the epistome and labrum are most similar between O. spongicola and O. edwardsi, and therefore, these two species appear to be most closely related.
Odontozona spongicola is the only one species of the genus reported to have association with hexactinellid sponges (Saito et al., 2017). On the other hand, Saito and Komatsu (2009) reported two species of Richardina also associated with hexactinellid sponges. Because of this similar life style, Saito and Komatsu (2009) proposed that O. spongicola may be necessary to transfer to the genus Richardina. In a recent molecular phylogeny analysis on Stenopodidea, O. spongicola is also revealed to be closer to the genus Richardina (Chen et al., 2016). The exact generic affinity of O. spongicola still awaits a full revision on the genus Odontozona.
description: Published as part of Chen, Chien-Lin & Chan, Tin-Yam, 2021, First record of the rare stenopodidean shrimp Odontozona spongicola (Alcock & Anderson, 1899) (Decapoda: Stenopodidea: Stenopodidae) from Indonesia, pp. 575-584 in Zootaxa 4915 (4) on pages 576-580, DOI: 10.11646/zootaxa.4915.4.8, http://zenodo.org/record/4461662