Cirolana improceros Bruce, 1986

Bruce, Niel L., 2017, Review of the species of the Cirolana ‘ parva - group’ (Cirolanidae: Isopoda: Crustacea) in Indonesian and Singaporean waters, Zootaxa 4317 (3), pp. 401-435 : 409-413

Cirolana improceros Bruce, 1986

( Figs 5–7 )

Cirolana improceros BruCe 1986: 182 , figs 125–126.— BruCe, Lew Ton & Poore, 2002: 143.— Jones & Grutter, 2007: 8.— RodCharoen, BruCe & Pholpunthin, 2016: 1980 .

Cirolana Cf. improceros .— Sidabalok, 2013: 52.

Type and type locality. The holotype is held at QM; and the type locality is Nina Bay, Hinchinbrook Island, Qld, 18°20.0'S, 146°17.5'E (QM W9836).

Material examined. All Indoneisa. 1 ♂ (5.2 mm), 1 ♀ (4.2 mm), Pulau Pombo, Maluku, 03°'31'22.1''S, 128°22'31.8''E, 2 November 2011, hand collection on rubble from sandy beach, coll. C.M. Sidabalok and party (MZB Cru.Iso 028). 3 ♂ (5.2, 6.3 [dissected and illustrated], 6.8 mm [dissected and illustrated]), 2 ♀ (4.5, 5.3 mm), 5 mancas (unmeasured), Waiwo, Raja Ampat, 00°26'15.8''S, 130°46'42.1''E, 5 August 2015, hand collection on intertidal reef, rubble, coll. C.M. Sidabalok and party (MZB Cru.Iso 062). 1 ♂ (5.5 mm), Waiwo, Raja Ampat, 00°26'15.8''S, 130°46'42.1''E, 5 August 2015, hand collection on intertidal reef, rubble, coll. C.M. Sidabalok and party (MTQ W52893). 2 ♂ (5.5, 6.9 mm), 5 ♀ (4.1, 4.2, 4.5, 4.6, 5.0 mm), 4 manca (2.0, 2.0, 3.0, 3.0 mm), Waiwo, Raja Ampat, 00°26'15.8''S, 130°46'42.1''E, 4 August 2015, hand collection on intertidal reef, rubble, coll. C.M. Sidabalok and party (MZB Cru.Iso 063). 2 ♂ (4.5, 6.9 mm), 3 ♀ (3.2, 3.6, 4.5, 5.0 mm), 1 manca (2.1 mm), Saleyo, Waiwo, Raja Ampat, 00°26'16.1''S, 130°46'50.2''E, 6 August 2015, hand collection on intertidal reef, rubble, coll. C.M. Sidabalok and party (MZB Cru.Iso 064).

Description (male). Body 3.4 times as long as greatest width, widest at pereonite 5, lateral margins subparallel. Eyes separated by about 72% width of head, eye colour black. 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. Pleon with pleonite 1 visible in dorsal view; pleonites 3–5 posterior margin smooth; posterolateral angles of pleonite 2 forming acute point, extending posteriorly to anterior of pleonite 3; pleonite 3 with posterolateral margins extending clearly beyond posterior margin of pleonite 5, acute; posterolateral margin of pleonite 4 narrowly rounded, clearly extending beyond posterior margin of pleonite 5. Pleotelson 0.7 times as long as anterior width; lateral margins convex, margins weakly serrate, posterior margin evenly rounded, with small distinct median point, with 8 RS.

Antennula peduncle articles 1 and 2 entirely fused; flagellum with 10 articles, extending to anterior of pereonite 1, articles 3 and 4 0.9 time as long as combined lengths of articles 1 and 2, article 3 3 times as long as wide; flagellum with 10 articles, extending to anterior of pereonite 1. Antenna peduncle article 4 2.0 times as long as wide, 2.3 times as long as article 3, inferior margin with 4 short simple setae (distal); article 5 1.1 times as long as article 4, 2.4 times as long as wide, inferior margin without pappose setae; anterodistal angle with cluster of 6 long simple setae; antenna flagellum with 26 articles, extending to posterior of pereonite 3.

Frontal lamina 2.0 longer than posterior width, 1.6 longer than greatest width, lateral margins straight, diverging slightly towards anterior, anterior margin concave, with small median point.

Pereopod 1 basis 2.0 times as long as greatest width, superior distal angle without acute setae; ischium 1.1 times as long as basis, inferior margin with 3 setae, superior distal margin with 2 RS; merus inferior margin with 5 molariform RS, merus inferior margin with 1 simple seta, set as single row, superior distal angle with 2 setae; carpus inferior margin with 1 RS, carpus inferior margin with 1 simple seta; propodus 2.1 times as long as wide, inferior margin with 2 RS, inferior margin without simple setae, superior distal margin with 1 simple seta; dactylus 0.6 as long as propodus; inferior margin with setal fringe lacking. Pereopod 2 ischium inferior margin with 1 long acute RS, inferior distal margin with 3 RS, superior distal margin with 2 long RS; merus inferior margin with 5 stout RS, set as single row, inferior distal margin with 3 stout RS, superior distal margin with 2 stout RS; carpus inferior distal margin with 4 RS; propodus 2.7 as long as wide, with 2 clusters of acute RS, inferior margin with 2 RS, inferior distal margin with 1 long RS; dactylus 0.6 as long as propodus. Pereopod 3 similar to pereopod 2. Pereopod 6 similar to pereopod 7. Pereopod 7 basis 2.2 times as long as greatest width, superior margin convex; ischium 0.7 as long as basis, inferior margin with 5 RS, superior distal angle with 6 (3 biserrate) RS, inferior distal angle with 3RS; merus 0.6 as long as ischium, 0.6 times as long as wide, inferior margin with 2 RS, superior distal angle with 7 biserrate RS, inferior distal angle with 5 RS; carpus 0.8 as long as ischium, 2.6 times as long as wide, inferior margin with 4 RS, superior distal angle with 7 RS (2 biserrate), inferior distal angle with 7 RS (3 biserrate); propodus 0.9 as long as ischium, 4.7 times as long as wide, inferior margin with 3 clusters of RS, superior distal angle with 1 slender seta, inferior distal angle with 1 RS; dactylus 0.3 as long as propodus.

Penes medially united.

Pleopod 1 exopod 1.6 times as long as wide, lateral margin weakly convex, distally narrowly rounded, mesial margin weakly oblique, mesial margin convex, with PMS from distal half, with ~28 PMS; endopod 2.0 times as long as wide, distally subtruncate, lateral margin weakly concave, with PMS from distal one-third, mesial margin with PMS on distal margin only, endopod with ~13 PMS; peduncle 1.6 times as wide as long; mesial margin with 5 coupling setae. Pleopod 2 exopod with ~36 PMS, endopod with ~20 PMS; appendix masculina with parallel margins, 1.5 times as long as endopod, distally acute. Pleopod 3 exopod with ~39 PMS, endopod with ~10 PMS. Pleopod 4 exopod with ~38 PMS, endopod with ~8 PMS. Pleopod 5 exopod with ~41 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 with mesial short acute RS, posterior lobe about as long as endopod; rami extending to pleotelson apex, marginal setae in single tier, apices acute. Endopod apically deeply subequal bifid, mesial process prominent; lateral margin straight, proximal lateral margin with 1 RS, distal lateral margin with 1 RS; mesial margin strongly convex, with 4 RS. Exopod not extending to end of endopod, 3.0 times as long as greatest width, apically deeply subequal bifid, mesial process prominent; lateral margin straight, with 7 RS; mesial margin straight, distally convex, with 3 RS.

Female. Similar to male.

Variation. Of 14 specimens measured (MZB Cru.Iso 0 28, MZB Cru.Iso 0 62, MZB Cru.Iso 063), uropod exopod RS mesial margin with 2–3 (3 = 78.6%), lateral with 5–7 (5 = 57.1%, 6 = 28.6%, 7 = 14.3%); uropod endopod mesial margin with 3–5 (3 = 50%, 4 = 42.9%, 5 = 7.1%), lateral margin with 2 (100%). All current material has lower RS numbers on uropod endopod lateral than the Australian material (2 vs 3) which might indicate some regional intraspecific variation.

Remarks. Cirolana improceros can be identified by the lack of a setal fringe on the male pereopod 1, pleonite 3 not extending beyond posterior of pleonite 4 with both pleonites 3 and 4 extend beyond the posterior margin of pleonite 5 in lateral view, medially united penes, uropod apices deeply subequal bifid with mesial process more prominent. Cirolana improceros is most similar to C. andamanensis (see remarks on C. andamanensis ). Another similar species is Cirolana paraerodiae Müller & Salvat, 1993 from French Polynesia, in both species having medially united penes, a similarly shaped uropodal endopod and exopod, exopod apex with mesial process prominent and pointed tip appendix masculina. Cirolana improceros differs in having an endopod pleopod 1 distally wider and a more slender frontal lamina.

Distribution. Maluku, Raja Ampat (West Papua) to Hinchinbrook Island, Australia ( Bruce 1986) ( Fig 1 ).

Figures

FIGURE 1. Distribution map of Cirolana ‘ parva group’ in Indo-Australian region (C – H, Indonesia; I, PNG; J – K, Australia). LoCation symbols: A = Thailand, B = Singapore, C = Lombok, D = Bitung, E = Pulau Pombo, Maluku, F = Raja Ampat, G = Kei Islands, H = Kaimana, I = Madang, J = Lizard Island, K = HinChinbrook Island. SpeCies symbols: Cirolana andamanensis (-), Cirolana arafurae (×), Cirolana improceros (v), Cirolana leptanga (O), Cirolana siamensis (O), Cirolana stenoura (A), Cirolana thailandica (Ł), Cirolana molari (Ɨ), Cirolana peisanae (+), Cirolana duo (Ŧ).

FIGURE 5. Cirolana improceros, ♂ (6.8 mm, MZB Cru. Iso 062) (A – C, F – G, I), ♂ (6.3 mm, MZB. Cru. Iso 062) (D – E, H): A, dorsal view; B, lateral view; C, frons; D, antennula; E, antenna pedunCle; F, head; G, penial openings; H, pleotelson; I, pleon.

FIGURE 6. Cirolana improceros, ♂ (6.3 mm, MZB Cru. Iso 062): A, pereopod 1; B, pereopod 2; C, pereopod 6; D, pereopod 7; E, uropod; F, uropod apiCes.

FIGURE 7. Cirolana improceros, ♂ (6.3 mm, MZB Cru. Iso 062): A, pleopod 1; B, pleopod 2; C, pleopod 3; D, pleopod 4; E, pleopod 5.