Cirolana indica Nierstrasz, 1931

Sidabalok, Conni M. & Bruce, Niel L., 2016, Redescription of three cirolanid isopods (Crustacea: Peracarida) from Indonesia, Zootaxa 4114 (3), pp. 277-290 : 278-284

Cirolana indica Nierstrasz, 1931

( Figs 1–5 )

Cirolana indica Nierstrasz, 1931 , figs 8–13.— Bruce, 1986: 220.— Brusca, Wetzer & France, 1995: 18.

Material examined. Holotype ♀ (11.5 mm), Siboga Expedition, Bajo Bay , Flores, Indonesia, Station 50, 40 m, 16 – 18 April 1899 ( ZMA. CRUS.I. 100605).

Non-type material. Singapore series: 1 ♂ (12.4 mm), St John’s Island, between Tanjong Hakim and Tanjong Lokos, 01°13.127'N, 103°50.728'E, 6 March 2014, 36.4 m, overnight baited trap, coll. Helen Wong & party, OTC-0064 OTR 307 ( ZRC.2015.0466). 1 ♀ (7.0 mm), same data as previous, OTC-0063 (MTQ W34356). 1 ♀ (11.3 mm), same data as previous, OTC-0070 (MTQ W34357). 3 ♀ (10.4, 10.9 [dissected], 11.5 mm), same data as previous OTC-0065 ( ZRC.2015.0467). 1 ♀ (9.0 mm), same data as previous, OTC-0067 ( ZRC.2015.06468). 1 ♀ (9.0 mm), same data as previous, OTC-0069 ( ZRC.2015.06469). 1 ♂ (9.7 mm, dissected), St John’s Island, 01°13.786'N, 103°46.893'E, 11 December 2013, dredge on mud and sand, 24.3–27.6 m, SEA 2023, DR239, CMBS Seabed, coll. Swee Cheng & party ( ZRC.2015.06470). 1 ♂ (9.1 mm, dissected), off west Pulau Berka, 01°11.138'N, 103°44.612'E, 21 October 2013, 18 m, dredge on sand and shell, SEA 1524 CMBS, DR222, coll. Swee Cheng and party ( ZRC.2015.06471). 2 ♀ (7.0, 10.2 mm), between St John’s and Lazarus Islands, 1.218718°N, 103.853968°E, 31 May 2013, stn SW 137, SS4940, overnight baited trap, 25 m coll. N.L. Bruce & J.K. Lowry (MTQ W34358). 1 manca (4.5 mm) between St John’s and Lazarus Islands, 1.218718°N, 103.853968°E, 31 May 2013, stn SW 138, SS4941, overnight baited trap, 13.5 m, coll. N.L. Bruce & J.K. Lowry ( ZRC.2015.0472). 1 ♀ (10.4 mm), off Raffles Lighthouse, 1°09'652”N, 103°44'908”E, 5 June 2013, SS 4248, stn DR 183, dredge, 42.1– 39.7 m, coll. Tan Koh Siang and party, ( ZRC.2015.06473).

Indonesia series: 1 ♂ (8.4 mm), 10 ♀ (6.9–10.9 mm, average 8.5 mm), 4 mancas (5.9, 6.0, 6.0, 6.5 mm), Teluk Nara, Lombok, 8°33'04.26''S, 116°04'26.52''E, trap 40 m, 13 August 2014, coll. C.M. Sidabalok and party ( MZB Cru.Iso.045). 6 ♀ (9.3, 9.5, 9.7, 9.9, 10.8, 11.0 mm), Teluk Kodek, Lombok, 8°24'13.44''S, 116°04'19.02''E, trap 25 m, 7 August 2014, coll. C.M. Sidabalok and party ( MZB Cru.Iso.046). 1 ♀ (10 mm), Teluk Mentigi, Lombok, 8°21'.26.94''S, 116°07'19.32''E, trap 50 m, 14 August 2014, coll. C.M. Sidabalok and party (MTQ W34359).

Description (male). Body 2.9 times as long as greatest width, dorsal surfaces smooth, widest at pereonite 4, lateral margins subparallel. Rostral point projecting anteriorly, not ventrally folded. Eye colour black, eyes separated by about 58 % width of head. Pereonite 1 and coxae 2–3 each with posteroventral angle rounded; coxae 5–7 without oblique carina; posterior margins of pereonites 5–7 smooth. Pleon with pleonite 1 visible in dorsal view; pleonites 3–5 posterior margin smooth; posterolateral angles of pleonite 2 forming acute point, not posteriorly produced; pleonite 3 with posterolateral margins extending clearly beyond posterior margins of pleonites 4 and 5, acute; posterolateral margin of pleonite 4 clearly extending beyond posterior margin of pleonite 5, acute. Pleotelson 0.8 times as long as anterior width, dorsal surface without longitudinal carina; lateral margins convex, margins smooth, posterior margin evenly rounded, without median point, with 10–14 robust setae.

Antennula peduncle articles 1 and 2 distinct, articulated; article 2 0.6 time as long as article 1, articles 3 and 4 as long as combined lengths of articles 1 and 2, article 3 1.3 times as long as wide; flagellum with 17 articles, extending to anterior of pereonite 1. Antenna peduncle article 4 1.5 times as long as wide, 2.3 times as long as article 3, inferior distal margin with 1 simple setae; article 5 1.2 times as long as article 4, 2.3 times as long as wide, anterodistal angle with cluster of 2 short simple setae and 2 long setae; flagellum with 38 articles, extending to middle of pereonite 4.

Frontal lamina posterior margin concave, longer than greatest width, lateral margins straight and parallel, anterior margin rounded, without small median point.

Mandible molar process anterior margin with 23 flat teeth; with proximal cluster of long simple setae; right mandible spine row composed of 10 spines, left mandible spine row with 10 spines; palp article 2 with 24 distolateral setae, palp article 3 with 7 robust biserrate setae. Maxillula mesial lobe with 3 large and circumplumose RS; lateral lobe with 8 RS. Maxilla lateral lobe with 4 long simple setae; middle lobe with 14 long simple setae; mesial lobe with 2 distal simple setae and 5 proximal simple and plumose setae. Maxilliped palp article 2 mesial margin with 12 slender setae, lateral margin distally with 2 slender setae; article 3 mesial margin with 9 slender setae, lateral margin with 9 slender setae; article 4 mesial margin with 9 slender setae, lateral margin with 6 slender setae; article 5 distal margin 13 setae, lateral margin with 7 setae; endite with 4 long CPS, and 2 coupling setae.

Pereopod 1 basis 4.7 times as long as greatest width; ischium 0.7 time as long as basis,; merus inferior distal margin with 1 simple setae; carpus inferior distal margin with 2 simple setae; propodus 3.3 times as long as wide, inferior margin with 6 acute RS and 4 simple setae, superior distal with 4 simple setae; dactylus 0.4 as long as propodus. Pereopod 2 ischium inferior margin with 1 1 simple seta, inferior distal margin with 1 RS, superior distal margin with 4 long simple setae; merus inferior margin with 4 stout RS, set as single row, inferior distal margin with 4 stout RS, superior distal margin with 2 acute RS and 3 stout RS; carpus inferior distal margin with 4 RS; propodus 1.8 as long as wide, inferior margin with 3 clusters of acute RS (set as 1, 1, 1), inferior distal margin with 1 long RS and 1 simple seta. Dactylus as long as propodus. Pereopod 3 similar to pereopod 2. Pereopod 6 similar to pereopod 7, only lack of the setae. Pereopod 7 basis 2.2 times as long as greatest width, superior margin weakly convex; ischium 0.7 as long as basis, inferior margin with 3 RS (set as 1 and 2), superior distal angle with 3 long RS, inferior distal angle with 3 long RS; merus 0.9 as long as ischium, 1.8 times as long as wide, inferior margin with 9 RS (single cluster), superior distal angle with 11 RS, inferior distal angle with 7 RS; carpus 1.1 as long as ischium, 2.8 times as long as wide, inferior margin with 9 RS (set as 5 and 4), superior distal angle with 6 RS, inferior distal angle with 6 RS; propodus as long as ischium, 5.5 times as long as wide, inferior margin with 3 clusters of RS (set as 2, 3 and 3), superior distal angle with 3 slender setae, inferior distal angle with 3 RS; dactylus 0.4 as long as propodus.

Penes separated by 10% sternal width, flat lobes.

Pleopod 1 exopod 1.8 times as long as wide, lateral margin straight, distally narrowly rounded with strongly oblique medial margin, mesial margin strongly convex, with ~53 PMS from distal half; endopod 2.5 times as long as wide, distally narrowly rounded, lateral margin straight with PMS from distal one-third, mesial margin with PMS from distal one-third, endopod with ~32 PMS; peduncle 1.8 times as wide as long; mesial margin with 5 coupling setae. Pleopod 2 exopod with ~77 PMS, endopod with ~33 PMS; appendix masculina with parallel margins as long as endopod, distally bluntly rounded. Pleopod 3 exopod with ~92 PMS, endopod with ~29 PMS. Pleopod 4 exopod with ~90 PMS, endopod with ~24 PMS. Pleopod 5 exopod with ~109 PMS. Pleopods 2–5 peduncle distolateral margin with prominent acute RS, 3–5 endopods with distomesial serrate scales.

Uropod peduncle ventrolateral margin without RS, lateral margin without medial short acute robust seta, posterior lobe about two-thirds as long as endopod; rami extending beyond pleotelson, marginal setae in single tier, apices narrowly rounded. Endopod apically not bifid; lateral margin straight, proximal lateral margin with 4 RS; distal lateral margin with 2 RS, mesial margin straight, with 6 RS. Exopod not extending to end of endopod, 4 times as long as greatest width, apically not bifid; lateral margin straight, with 6 RS; mesial margin straight, with 5 RS.

Female. No ovigerous females present in the collected material. Non-ovigerous females have a similar morphology to males except for the sexual characters and the lack of setae on pereopod 7; body size is slightly smaller.

Size. Adult males 8.4–12.4 mm, mean 9.9 mm (n = 4); adult females 6.9–11.5 mm, mean 9.2 mm (n = 27).

Variation. Number of RS on pleotelson margin varies (n = 31), 10 RS (53%), 12 RS (44%) and 14 RS (3%).

Distribution. From Singapore to central Indonesia at depths of 18 to 50 metres.

Remarks. Cirolana indica can be readily recognized by the unique morphology of pereopod 1, which is slender in comparison to other species of Cirolana , with a distinctive row of apically curved robust setae on the distal margin of the propodal palm, and also lacks the typical molariform robust setae on the inferior margin of the merus. The two male specimens from Singapore have abundant long setae on pereopod 7, an apparently unique form of sexual dimorphism otherwise not know in the Cirolana . Sexual dimorphism on pereopod 1 is well known in Cirolana , with a dimorphic pereopod 1 being commonly found in some species of the “ Cirolana parva group” such as Cirolana arafurae Bruce, 1986 , Cirolana erodiae Bruce, 1986 , Cirolana mekista Bruce, 1986 and Cirolana reprigrata Bruce, 1994 . Other generic characters such as shape of the frontal lamina, morphology of pereopods 2, 6 and 7, proportion of the peduncular articles of the antennula and antenna, shape of the pleopod 1 peduncle and rami and the basal attachment of the appendix masculina all conform to the genus Cirolana .

Figures

FIGURE 1. Cirolana indica, holotype (11.5 mm) (A – C); ♂ (12.4 mm, ZRC. 2015.0466) (D, H); ♂ (9.1 mm, ZRC. 2015.0471) (E, F, G). A, dorsal view; B, lateral view; C, frons; D, pleotelson; E, antenna; F, antennula; G, uropod; H, penial openings.

FIGURE 2. Cirolana indica, ♂ (9.7 mm, ZRC. 2015.0470). A, maxilla; B, maxillula; C, maxilliped; D, right mandible; E, molar process of right mandible.

FIGURE 3. Cirolana indica, ♂ (9.7 mm, ZRC. 2015.0470) (A, B); ♂ (9.1 mm, ZRC. 2015.0471) (C). A, pereopod 1; B, pereopod 2; C, pereopod 6.

FIGURE 4. Cirolana indica, ♂ (9.7 mm, ZRC. 2015.0470) (A); ♀ (10.9 mm, ZRC. 2015.0467) (B). A and B, pereopod 7.

FIGURE 5. Cirolana indica, ♂ (9.7 mm, ZRC. 2015.0470). A – E, pleopods 1 – 5 respectively.