Cirolana andamanensis Rodcharoen, Bruce & Pholpunthin, 2016, sp. nov.
Creators: name: Eknarin Rodcharoen
name: Niel L. Bruce
name: Pornsilp Pholpunthin
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Cirolanidae
Cirolana
Cirolana andamanensis

description: Cirolana andamanensis sp. nov.
(Figures 2 – 6)
Material examined
Holotype, ♂ (6.7 mm), Nai yang beach, Phuket Province, 08°05'07" N, 98°17 ’ 06" E, 14 December 2012, trapped at a depth of 1 m, coral rubble, coll. E. Rodcharoen (PSUZC – CR 0282-01).
Paratypes, all material from Andaman Sea coast. 12 ♂ (6.7, 7.0, 5.7, 6.5, 6.2, 6.5, 6.7, 6.6, 6.0, 7.0, 6.5, 6.4 mm [dissected]), 3 ♀ (6.2, 6.2, 6.0 mm [dissected]), 23 specimens unmeasured, same data as holotype (PSUZC – CR 0282-02; MTQ W 34353). 4 ♂ (7.8, 6.6, 7.3, 6.2 mm [dissected]), 10 ♀ (6.9, 6.8, 6.5, 6.8, 7.3, 6.7, 6.4, 6.4, 6.3, 7.1 mm [dissected]), Koh Lidee, Satun Province, 06°47 ’ 17" N, 99°45 ’ 49" E, 1 February 2014, trapped at a depth of 1 m, coral rubble, coll. E. Rodcharoen (PSUZC – CR 0282-03). 15 ♂ (unmeasured), Koh Phayam, Ranong Province, 09°42 ’ 36" N, 98°23 ’ 41" E, 22 December 2012, trapped at a depth of 3 m, coral rubble, coll. E. Rodcharoen (PSUZC – CR 0282-04). 23 ♂ (unmeasured), Laem Pakarang, Phang Nga Province, 08°44 ’ 11" N, 98°13 ’ 13" E, 3 August 2014, trapped at a depth of 2 m, coral rubble, coll. E. Rodcharoen (PSUZC – CR 0282-05). 18 ♂ (unmeasured), Ao Kham, Phuket Province, 07°49 ’ 51" N, 98°24 ’ 14" E, 6 August 2014, trapped at a depth of 1 m, coral rubble, coll. E. Rodcharoen (PSUZC – CR 0282-06). 28 ♂ (unmeasured), Talay Waek, Krabi Province, 07°57 ’ 28" N, 98°48 ’ 26" E, 15 January 2012, trapped at a depth of 5 m, coral rubble, coll. E. Rodcharoen (PSUZC – CR 0282-07). 7 ♂ (unmeasured), Ratchamongkol Beach, Trang Province, 07°31 ’ 17" N, 99° 18 ’ 17" E, 17 March 2012, trapped at 1 m depth, rocky shore, coll. E. Rodcharoen (PSUZC – CR 0282-08). 23 ♂ (unmeasured), Koh Adang, Satun Province, 06°30 ’ 21" N, 99°18 ’ 19" E, 28 December 2011, trapped at a depth of 10 m, coral reef, coll. E. Rodcharoen (PSUZC – CR 0282-09).
Description of male. Body 3.0 times as long as greatest width, widest at pereonite 5, lateral margins subparallel (Figure 2 A). Eyes dark brown, separated by about 64% width of head (Figure 2 C). Pereonite 1 and coxae 2 – 3 each with posteroventral angle rounded; coxae 5 – 7 with entire oblique carina; posterior margins of pereonites 5 – 7 smooth (Figure 2 B). Pleon (Figure 2 E) with pleonite 1 largely concealed by pereonite 7; pleonites 3 – 5 posterior margins smooth; posterolateral angles of pleonite 2 forming acute point, extending posteriorly to anterior of pleonite 4; pleonite 3 with posterolateral margins extending to but not beyond posterior margin of pleonite 5, acute; posterolateral margin of pleonite 4 rounded, clearly extending beyond posterior margin of pleonite 5; pleonite 5 with posterolateral angles overlapped by lateral margins of pleonite 4. Pleotelson 0.9 times as long as anterior width, dorsal surface without longitudinal carina; lateral margins weakly convex; margins smooth, posterior margin converging to caudomedial point, with small distinct median point, with 8 RS (Figure 6 E, F).
Antennula (Figure 2 F) peduncle articles 1 and 2 entirely fused; articles 3 and 4 0.9 times as long as combined lengths of articles 1 and 2; article 3 2.5 times as long as wide, flagellum with 10 articles extending to anterior of pereonite 1. Antenna (Figure 2 G) peduncle article 4 1.8 times as long as wide, 2.1 times as long as article 3; article 5 1.1 times as long as article 4, 2.4 times as long as wide, inferodistal angle with 1 pappose seta, anterodistal angle with cluster of 2 pappose setae and 5 long simple setae; flagellum with 24 articles, extending to posterior of pereonite 4.
Frontal lamina (Figure 2 D) pentagonal, 1.8 times as long as posterior width, 1.6 times as long as greatest width, lateral margins straight, diverging slightly towards anterior, anterior margin acute, with small median point.
Mandible molar process (Figure 3 A, C) anterior margin with 19 flat teeth; with proximal cluster of long simple setae; right mandible spine row composed of 7 spines, left with 8 spines; palp articles 2 with 25 distolateral setae; palp article 3 lateral margin with 18 robust biserrate setae, distal margin with 3 biserrate setae (Figure 3 B). Maxillule (Figure 3 E) mesial lobe with 3 large and circumplumose RS; lateral lobe with 10 RS (plus 1 slender seta). Maxilla (Figure 3 D) lateral lobe with 5 long simple setae, middle lobe with 11 long simple setae, mesial lobe with 2 distal simple setae and 12 proximal simple and plumose setae. Maxilliped palp (Figure 3 F) article 2 mesial margin with 5 slender setae, lateral margin distally with 1 slender seta; article 3 mesial margin with 13 slender setae, lateral margin with 6 slender setae; article 4 mesial margin with 14 slender setae, lateral margin with 5 slender setae; article 5 distal margin with 17 setae, lateral margin with 4 setae; endite (Figure 3 G) with 6 long CPS and 2 coupling setae.
Pereopod 1 (Figure 4 A, B) basis 2.3 times as long as greatest width, inferior distal angle with cluster of 3 acute setae; ischium 0.6 times as long as basis, inferior margin with 1 acute seta, inferior distal angle with 2 RS, superior distal margin with 2 RS; merus inferior margin with 5 molariform RS (set in rows of 3 and 2), superior distal angle with 3 setae; carpus inferior margin with 1 RS (plus 1 long slender seta); propodus 1.8 times as long as wide, inferior margin with 2 RS; dactylus (Figure 4 C) 0.8 times as long as propodus, inferior margin without setal fringe. Pereopod 2 (Figure 4 D) ischium inferior margin with 3 stout, bluntly rounded RS, superior distal margin with 2 RS; merus inferior margin with 7 stout RS (set in rows of 4 and 3), superior distal margin with 4 acute RS; carpus inferodistal angle with 3 RS (plus 1 long slender seta); propodus 2.9 times as long as wide; dactylus 0.6 times as long as propodus. Pereopod 3 similar to pereopod 2. Pereopod 4 (Figure 4 E) intermediate in form between pereopod 3 and pereopod 5. Pereopod 6 similar to pereopod 7. Pereopod 7 (Figure 4 F) longer than pereopod 6; basis 2.4 times as long as greatest width, superior margin convex, inferior margin with 2 palmate setae; ischium 0.6 times as long as basis, inferior margin with 5 RS (set in groups of 2 and 3), superior distal angle with 6 RS (2 biserrate), inferior distal angle with 3 RS; merus 0.7 times as long as ischium, 1.5 times as long as wide, inferior margin with 2 RS, superior distal angle with 10 RS (5 biserrate), inferior distal angle with 5 RS; carpus 0.8 times as long as ischium, 2.0 times as long as wide, inferior margin with 2 RS, superior distal angle with 10 RS (five biserrate), inferior distal angle with 9 RS (5 biserrate); propodus 1.0 time as long as ischium, 4.3 times as long as wide, inferior margin with 4 RS (set in groups of 2 and 2), superior distal angle with 3 slender setae (plus 1 RS), inferior distal angle with 2 RS; dactylus 0.3 times as long as propodus.
Penes (Figure 2 H) 2 low tubercles, penial openings separated by 3% of sternal width.
Pleopod 1 (Figure 5 A) exopod 1.6 times as long as wide, lateral margin weakly convex, distally broadly rounded, mesial margin strongly convex, with 28 PMS from distal onethird; endopod 2.1 times as long as wide, broadly rounded distally, lateral margin weakly concave, with 13 PMS on distal margin only; peduncle 1.7 times as wide as long, mesial margin with 5 coupling hooks. Pleopod 2 (Figure 5 B) exopod with 40 PMS, endopod with 15 PMS; appendix masculina with parallel margins, 1.4 times as long as endopod, distally acute. Pleopod 3 (Figure 5 C) exopod with 40 PMS, endopod with 11 PMS. Pleopod 4 (Figure 5 D) exopod with 44 PMS, endopod with 9 PMS. Pleopod 5 (Figure 5 E) exopod with 39 PMS. Pleopods 2 – 5 peduncle distolateral margin with prominent acute RS, endopods 3 – 5 with distomesial serrate scales.
Uropod (Figure 6 A) peduncle ventrolateral margin with 2 RS (plus 1 long seta) (Figure 6 B), lateral margin with 1 medial short acute RS, posterior lobe about one-half as long as endopod; rami extending to pleotelson apex, marginal setae in single tier. Endopod (Figure 6 A, D) apically deeply bifid, medial process weakly prominent, lateral margin weakly convex, without prominent excision, with 2 RS, mesial margin weakly convex, with 4 RS. Exopod (Figure 6 A, C) not extending to end of endopod, 0.8 times as long as endopod, 2.9 times as long as greatest width, apically deeply bifid, medial process prominent, lateral margin weakly convex, with 7 RS, mesial margin convex, with 3 RS.
Female
Of similar appearance to the male.
Size
Adult males (n = 17) 5.7 – 7.8 mm (mean 6.6 mm); females (n = 13) 6.0 – 7.3 (mean 6.6 mm).
Variation
Pleotelson (n = 30; 17 ♂ and 13 ♀) with 7 – 10 RS, with 8 RS (4 + 4) most frequent (94%), and 7 (3%) and 10 (3%) occurring only once. Uropod endopod mesial margin with 3 – 5 RS, with 4 (84%) most frequent, and 5 (13%) and 3 (3%) occurring only once, lateral margin with 2 – 3 RS, with 2 (94%) most frequent and 3 (6%); exopod mesial margin with 2 – 3 RS, with 3 (97%) most frequent and 2 (3%) occurring only once, lateral margin with 6 – 8, with 7 (74%) most frequent, 6 (20%) and 8 (6%).
Remarks
Cirolana andamanensis sp. nov. is characterised by the antennula peduncle having articles 1 and 2 entirely fused; antenna flagellum extending to posterior of pereonite 4; pereopod 1 on male lacking a setal fringe; pleonite 3 with posterolateral margins extending to but not beyond posterior margin of pleonite 5; penes are two low tubercles with the openings separated by 3% of sternal width; pleopod 1 with endopod lateral margin weakly concave; appendix masculina distally acute, with parallel margins, 1.4 times as long as endopod; uropod peduncle ventrolateral margin with two robust setae (plus one long seta), rami extending to pleotelson apex; endopod apically deeply bifid, mesial process weakly prominent, lateral margin with two robust setae, mesial margin with four robust setae; exopod apically deeply bifid, medial process prominent, lateral margin with seven robust setae, mesial margin with three robust setae; pleotelson with eight robust setae.
The lack of a setal fringe on the male pereopod 1 separates C. andamanensis sp. nov. from the eleven species within the group that do have a setal fringe on the male pereopod 1. Of these, C. andamanensis sp. nov. is most similar to C. aldabrensis Schotte & Kensley, 2005 (Aldabra Atoll), C. mimulus Schotte & Kensley, 2005 (Seychelles) and C. nielbrucei Brusca, Wetzer & France, 1995 (Pacific coast of Mexico) all having an antennula peduncle with three segments; antenna flagellum extending to pereonite 4 and appendix masculina about 1.4 – 1.5 times as long as endopod. Cirolana mimulus, can be separated from C. andamanensis by having the appendix masculina bent laterally (vs straight) and pleopod 1 endopod with straight lateral margin (vs concave). C. aldabrensis has fewer robust setae on lateral margin of uropod exopod and pleotelson margin than Cirolana andamanensis sp. nov.; lateral margin of uropod exopod with five robust setae (vs seven robust setae) and pleotelson margin with six robust setae (vs eight robust setae). Moreover, C. aldabrensis has the uropod exopod apically deeply bifid, with a prominent lateral process (vs prominent mesial process) and pleopod 1 endopod with lateral margin straight (vs concave). Cirolana nielbrucei known only from the East Pacific (Gulf of California), can be clearly distinguished by the characters of the pleotelson, which is triangular with angled and straight lateral margins, with six to seven robust setae (vs lateral margins weakly convex, with seven to ten robust setae).
Of the species occurring in Thailand, Cirolana andamanensis sp. nov. can be separated from the sympatric Cirolana phangnga sp. nov. by the antennula peduncle having articles 1 and 2 entirely fused (vs articles 1 and 2 distinct, articulated); pereopod 1 on male lacking setal fringe (pereopod 1 on male with setal fringe on carpus and propodus); penes two low tubercles, penial opening separated by 3% of sternal width (penes two low tubercles, penial opening separated by 12% of sternal width); uropod peduncle ventrolateral margin with two robust setae and one long seta, rami extending to pleotelson apex (vs uropod peduncle ventrolateral margin with two robust setae and plus three long setae, rami extending beyond pleotelson); apex of rami deeply bifid, mesial process prominent (vs apex of rami deeply bifid, lateral process prominent). The same character states of the antennula peduncle, male pereopod 1, penes and uropod peduncle also separate C. andamanensis from other species in the C. parva group currently known from Thailand.
Etymology
The epithet andamanensis alludes to the Andaman Sea, in which the type locality lies.
description: Published as part of Eknarin Rodcharoen, Niel L. Bruce & Pornsilp Pholpunthin, 2016, Description of four new species of the Cirolana ' parva group' (Crustacea: Isopoda: Cirolanidae) from Thailand, with supporting molecular (COI) data, pp. 1935-1981 in Journal of Natural History 50 (31 - 32) on pages 6-15, DOI: 10.1080/00222933.2016.1180718, http://zenodo.org/record/269029