Cirolana duo, Bruce, 2017

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 : 428-434

Cirolana duo sp. nov.

( Figs 17–20 )

Material examined. Holotype, ♂ (5.8 mm), Teluk Kodek, Lombok, Indonesia 8°24'13.44''S, 116°04'19.02''E, 11 August 2014, hand collection on intertidal reef, rubble, coll. C.M. Sidabalok and party ( MZB Cru.Iso 068).

Paratypes. Indonesia series. 3 ♂ (4.1 [dissected], 4.6, 5.1 mm), 9 ♀ (3.9–6.1 mm, average 4.6 mm), Teluk Medana, Lombok, 8°21'34.00''S, 116°07'25.59''E, 14 August 2014, diving 6 m, rubble and dead coral head, coll. C.M. Sidabalok and party ( MZB Cru.Iso 069) . 2 ♂ (3.9, 4.4 mm), same data as previous (MTQ W52901). Singapore series. 3 ♂ (not measured), Pulau Tekukor , 01°13.879'N, 103°50.318'E, 12 March 2014, trap at 1.6 m, coll. Razali and party, OTR 320 OTC 0 0 38 ( ZRC 2017.0772 ) . 2 ♂ (not measured), same data as previous (MTQ W52902) . 4 ♂ (6.5 [dissected], 7.0, 10.0, 10.0 [dissected] mm), same data as previous, OTC 0 0 43 ( ZRC 2017.0773 ) . 1 ♂ (8.4 mm), same data as previous, OTC 0 0 81 ( ZRC 2017.0774 ) .

Description. Body 4.2 times as long as greatest width, widest at pereonite 5, lateral margins subparallel. Eyes separated by about 85% 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 largely concealed by pereonite 7; 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 rounded, clearly extending beyond posterior margin of pleonite 5. Pleotelson 0.9 times as long as anterior width; lateral margins weakly convex, margins weakly serrate, posterior margin evenly rounded, with small distinct median point, with 8 RS.

Antennula peduncle articles 1 and 2 entirely fused; articles 3 and 4 0.8 times as long as combined lengths of articles 1 and 2, article 3 2.3 times as long as wide; flagellum with 7 articles, extending to anterior of pereonite 1. Antenna peduncle article 4 1.6 times as long as wide, 1.8 times as long as article 3; article 5 as long as article 4, 1.7 times as long as wide; flagellum with 23 articles, extending to posterior of pereonite 4.

Frontal lamina 1.5 longer than posterior and greatest width, lateral margins straight, diverging slightly towards anterior, anterior margin acute, forming median point.

Mandible molar process anterior margin with 17 flat teeth; with proximal cluster of long simple setae; right mandible spine row composed of 12 spines; palp article 2 with 13 distolateral setae, palp article 3 with 14 robust biserrate setae. Maxillula mesial lobe with 3 large and CPS RS; lateral lobe with 9 RS. Maxilla lateral lobe with 3 long simple setae; middle lobe with 6 long simple setae; mesial lobe with 5 distal simple setae, with 5 proximal simple and 3 plumose setae. Maxilliped palp article 2 mesial margin with 3 slender setae, lateral margin distally with 1 slender seta; article 3 mesial margin with 6 slender setae, lateral margin with 4 slender setae; article 4 mesial margin with 8 slender setae, lateral margin with 2 slender setae; article 5 distal margin 9 setae, lateral margin with 2 setae; endite with 3 long CPS, and 2 coupling setae.

Pereopod 1 basis 2.2 times as long as greatest width, superior distal angle without cluster of acute setae, inferior distal angle with cluster of 2 acute setae; ischium 0.6 times as long as basis, inferior margin without setae, inferior distal margin with 2 RS, superior distal margin with 1 RS; merus inferior margin with 9 molariform RS, set as two rows, with 2 simple setae, inferior distal margin with 1 RS, superior distal angle with 1 seta; carpus inferior margin with 1 simple seta; propodus 2 times as long as wide, inferior margin with 1 RS, inferior distal margin with 1 large RS, superior distal with 2 simple setae; 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 RS; merus inferior margin with 4 stout RS, set as single row, inferior distal margin with 3 stout RS, superior distal margin with 6 stout RS; carpus inferior distal margin with 3 RS; propodus 2.5 as long as wide, with 2 clusters of acute RS, inferior margin with 2 RS, inferior distal margin with 1 long RS; dactylus 0.4 as long as propodus. Pereopod 3 similar to pereopod 2. Pereopod 6 similar to pereopod 7. Pereopod 7 basis 2.3 times as long as greatest width, superior margin convex, superior margin with 2 palmate setae; ischium 0.6 as long as basis, inferior margin with 3 RS (set in group of 2), superior distal angle with 4 RS, inferior distal angle with 2 RS; merus 0.6 as long as ischium, 1.6 times as long as wide, inferior margin with 1 RS, superior distal angle with 6 RS (2 biserrate), inferior distal angle with 6 RS; carpus 0.8 as long as ischium, 2.3 times as long as wide, inferior margin with 2 RS, superior distal angle with 6 RS (3 biserrate), inferior distal angle with 8 RS (4 biserrate); propodus as long as ischium, 4.2 times as long as wide, inferior margin with 2 clusters of RS, superior distal angle with 1 slender seta and 2 RS, inferior distal angle with 2 RS; dactylus 0.2 as long as propodus.

Penes low tubercles, penial openings separated by 6% of sternal width.

Pleopod 1 exopod 1.6 times as long as wide, lateral margin weakly convex, distally narrowly rounded mesial margin weakly oblique; mesial margin strongly convex, with PMS from distal two-thirds, with ~23 PMS; endopod 2.1 times as long as wide, distally subtruncate, lateral margin straight weakly concave, with PMS from distal onethird, mesial margin with PMS on distal margin only, endopod with ~11 PMS; peduncle 1.6 times as wide as long. Pleopod 2 exopod with ~29 PMS, endopod with ~11 PMS; appendix masculina with parallel margins, 1.6 times as long as endopod, distally acute. Pleopod 3 exopod with ~31 PMS, endopod with ~11 PMS. Pleopod 4 exopod with ~34 PMS, endopod with ~8 PMS. Pleopod 5 exopod with ~33 PMS. Pleopods 2–5 peduncle distolateral margin with prominent acute RS, 3–5 endopods with distomesial serrate scales.

Uropod peduncle ventrolateral margin with 3 RS, lateral margin with mesial short acute RS, posterior lobe about as long as endopod; rami extending beyond pleotelson, marginal setae in single tier, apices acute. Endopod apically deeply subequal bifid, mesial process prominent; lateral margin weakly convex, 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, 2.8 times as long as greatest width, apically deeply subequal bifid, mesial process prominent; lateral margin straight, with 6 RS; mesial margin strongly convex, with 3 RS.

Female. Similar to male.

Variation. Sixteen individuals were measured (MZB Cru.Iso 068–069, MTQ W52901 and ZRC 2017.0774). Uropod exopod RS mesial margin with 3 (100%), lateral with 5–7 (6 = 64.6%, 5 = 29.4%, 7 = 6.0%); uropod endopod RS mesial margin with 3–5 (4 = 88.0%, 3 and 5 = 6.0% each), lateral margin with 2 (100%).

Remarks. Cirolana duo sp. nov. is most similar to Cirolana andamanensis in having a pointed tip of the appendix masculina, subequal deeply bifid uropodal apices with the mesial process prominent and lacking setal fringe on pereopod 1 inferior margin. Cirolana duo differs from all other ‘ parva -group’ species in having two rows of robust setae on the inferior margin of merus pereopod 1. It also has wider penial openings than that in similar species with closely spaced penial (6% vs 3%).

Distribution. Indonesia (Lombok) and Singapore; intertidal to 6 metres ( Fig 1 ).

Etymology. The epithet duo is the Latin for the defining character, i.e. the double row of robust setae on the merus of pereopod 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 17. Cirolana duo sp. nov., holotype ♂ (5.8 mm, MZB Cru. Iso 068) (A – E), paratype ♂ (4.1 mm, MZB. Cru. Iso 069) (F – J): A, dorsal view; B, lateral view; C, frons; D, head; E, pleon; F, uropod; G, uropod apiCes; H, antenna pedunCle; I, antennula; J, pleotelson.

FIGURE 18. Cirolana duo sp. nov., paratype ♂ (4.1 mm, MZB Cru. Iso 069): A, pereopod 1; B, pereopod 2; C, pereopod 6; D, pereopod 7.

FIGURE 19. Cirolana duo sp. nov., paratype ♂ (4.1 mm, MZB Cru. Iso 069): A, maxilliped; B, maxillula; C, maxilla; D, right mandible.

FIGURE 20. Cirolana duo sp. nov., paratype ♂ (4.1 mm, MZB Cru. Iso 069): A, pleopod 1; B, pleopod 2; C, pleopod 3; D, pleopod 4; E, pleopod 5.