Cirolana arafurae 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 : 404-409

Cirolana arafurae Bruce, 1986

( Figs 2–4 )

Cirolana arafurae BruCe, 1986: 171 , figs 117, 118.— RodCharoen, BruCe & Pholpunthin, 2016: 1979 . Not Cirolana arafurae .— Yu & Li 2001: 46; 2003: 260 (= Cirolana sp.).

Type and type locality. The holotype is held at ZMUC; type locality is Kei Islands , Indonesia, 5°34'S, 132°26'E.

Material examined. All Indonesia. 8 ♂ (3.5, 3.7, 3.8, 4.1, 4.2, 4.2, 4.5, 4.6 [dissected and illustrated] mm), 19 ♀ (3.0–4.9, average = 3.8 mm), Teluk Mentigi, Lombok, 8°21'.26.94''S, 116°07'19.32''E, 13 August 2014, trap 20 m, coll. C.M. Sidabalok and party ( MZB Cru.Iso 051) . 5 ♂ (3.9, 3.9, 3.9, 4.0, 4.0 mm), 5 ♀ (average = 3.8 mm), Teluk Mentigi, Lombok, 8°21'.26.94''S, 116°07'19.32''E, 13 August 2014, trap 20 m, coll. C.M. Sidabalok and party (MTQ W52892). 2 ♂ (3.7, 6.0 mm), 19 ♀ (3.5–4.8 mm, average = 4.0 mm), Teluk Mentigi, Lombok, 8°21'.26.94''S, 116°07'19.32''E, 13 August 2014, trap 7 m, coll. C.M. Sidabalok and party (MZB Cru.Iso 052). 1 ♂ (5 mm), Teluk Mentigi, Lombok, 8°21'.26.94''S, 116°07'19.32''E, 7 August 2014, dive 3 m, coll. C.M. Sidabalok and party (MZB Cru.Iso 053). 6 ♂ (5.0 [dissected and illustrated], 5.1, 5.4, 5.5, 5.5, 5.7 mm), 10 ♀ (4.0–5.0 mm, average = 4.6 mm), Teluk Kodek, Lombok, 8°24'13.44''S, 116°04'19.02''E, 7 August 2014, trap 7 m, coll. C.M. Sidabalok and party (MZB Cru.Iso 054). 1 ♂ (4.2 mm), Gili Trawangan, Lombok, 8°21'3.629''S, 116°01'37.74''E, 9 August 2014, diving 8 m, rubble and dead coral head, coll. C.M. Sidabalok and party (MZB Cru.Iso 055). 2 ♂ (3.6, 5.2 mm), 2 ♀ (3.8, 4.1 mm), Teluk Kombal, Lombok, 8°24'03.72" S, 116°04'54.13" E, 14 August 2014, trap 35m, coll. C.M. Sidabalok and party (MZB Cru.Iso 056). 1 ♂ (5.7 mm), 1 ♀ (5.5 mm), 2 manca (2.6, 3.0 mm), Batu Lima, Raja Ampat, 00°26'58.8''S, 130°41'51.8''E, 16 August 2015, diving 20 m, coll. rubble and dead coral head, M. Mofu and E. Umpain (MZB Cru.Iso 057). 1 ♂ (6.5 mm), Waiwo, Raja Ampat, 00°26'14.6''S, 130°47'01.1''E, 7 August 2015, trap 10 m, coll. M. Mofu and E. Umpain (MZB Cru.Iso 058). 1 ♂ (8 mm), Kepulauan Mansuar, Raja Ampat, 00°36'05.00''S, 130°33'30.2''E, 13 August 2015, diving 15 m, rubble and dead coral head, coll. E. Umpain (MZB Cru.Iso 059). 2 ♂ (4.0, 7.0 mm), Tanjung Putus, Raja Ampat, 00°30'29.5''S, 130°27'21.9''E, 15 August 2015, diving 20 m, rubble and dead coral head, coll. M. Mofu and R. Mambrasar (MZB Cru.Iso 060). 1 ♂ (5.9 mm), Saonek, Raja Ampat, 00°28'14.1''S, 130°46'43.7''E, 9 August 2015, trap 10 m, coll. M. Mofu and E. Mamberaku (MZB Cru.Iso 061).

Description (male). Body 3.0 times as long as greatest width, widest at pereonite 5, lateral margins subparallel. Eyes separated by about 78% 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 narrowly rounded, clearly extending beyond posterior margin of pleonite 4 and 5. Pleotelson 0.9 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 distinct, articulated; article 2 0.7 times as long as article 1, articles 3 and 4 0.8 times as long as combined lengths of articles 1 and 2, article 3 0.5 times as long as wide; flagellum with 11 articles, extending to anterior of pereonite 1. Antenna peduncle article 4 0.5 times as long as wide, 2.7 times as long as article 3; article 5 1.1 times as long as article 4, 2.1 times as long as wide; anterodistal angle with cluster of 4 long simple setae; extending to posterior of pereonite 4.

Frontal lamina 1.9 longer than posterior width, 1.3 longer than greatest width, lateral margins straight, diverging slightly towards anterior; anterior margin concave, with small median point.

Pereopod 1 basis 2.7 times as long as greatest width, superior distal angle without acute setae; ischium 0.5 times as long as basis, inferior margin without setae, superior distal margin with 1 RS; merus inferior margin with 7 molariform RS, set as single row, superior distal angle with 3 setae; carpus inferior margin with 1 RS; propodus 1.9 times as long as wide, inferior margin with 1 RS, inferior margin without simple setae, superior distal with 3 simple setae; dactylus 0.4 as long as propodus; inferior margin with setal fringe on propodus to distal half of merus. Pereopod 2 ischium inferior margin with 1 simple seta; distal margin with 1 RS and 2 molariform RS, superior distal margin with 1 long simple setae and 2 RS; merus inferior margin with 8 stout RS set as two rows (set in row of 5 and 3), superior distal margin with 3 acute 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 and 2 simple setae; dactylus 0.5 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, inferior margin with 2 palmate setae; ischium 0.6 as long as basis, inferior margin with 4 RS, superior distal angle with 2 RS, inferior distal angle with 2 RS; merus 0.7 as long as ischium, 1.8 times as long as wide, inferior margin with 1 RS, superior distal angle with 3 RS, inferior distal angle with 3 RS; carpus 1.2 as long as ischium, 2.5 times as long as wide, inferior margin with 3 RS, superior distal angle with 5 RS, inferior distal angle with 5 RS; propodus 1.1 as long as ischium, 4.6 times as long as wide, inferior margin with 2 clusters of RS, superior distal angle with 1 slender setae, inferior distal angle with 2 RS; dactylus 0.2 as long as propodus.

Penes opening flush with surface of sternite 7, penial openings separated by 12.5% of sternal width.

Pleopod 1 exopod 1.7 times as long as wide, lateral margin straight, distally narrowly rounded, mesial margin weakly oblique, mesial margin weakly convex, with PMS from distal one-third; endopod 2.1 times as long as wide, distally subtruncate, lateral margin weakly concave, with PMS on distal margin only, mesial margin with PMS on distal margin only; peduncle 1.4 times as wide as long; mesial margin with 5 coupling setae. Pleopod 2 appendix masculina basally swollen, 1.6 times as long as endopod, distally narrowly rounded. Pleopods 2–5 peduncle distolateral margin with prominent acute RS, 3–5 endopods with distomesial serrate scales.

Uropod peduncle ventrolateral margin with 4 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, lateral process prominent; lateral margin straight, proximal lateral margin with 2 RS; distal lateral margin with 1 RS, mesial margin weakly convex, with 4 RS. Exopod not extending to end of endopod, 3 times as long as greatest width, apically deeply subequal bifid, lateral process prominent; lateral margin weakly convex, with 5 RS; mesial margin straight, with 3 RS.

Female. Similar to male with the lack of setal fringe on the inferior margin of pereopod 1.

Variation. Uropod RS were measured from 16 specimens from Lombok (MZB Cru.Iso 051). Uropod exopod RS mesial margin with 2–3 (3 = 93.8%), lateral with 5–6 (5 = 81.3%); uropod endopod mesial margin with 3–5 (4 = 68.8%, 3 = 25%, 5 = 6.2%), lateral margin with 2–3 (3 = 68.8%). Males from Mentigi, Lombok and Tanjung Putus, Raja Ampat have the appendix masculina laterally finely bent (vs straight tip in the original description) with the similar counts of pleotelson and uropod RS. The largest male from Lombok is 30% smaller (5.4 vs 7.5 mm) than the largest male in original description ( Bruce 1986).

Remarks. Cirolana arafurae is characterised by the setose fringe on the propodus–merus of male pereopod 1, posterolateral margin of pleonite 3 not extending to posterior margin of pleonite 5, penial openings are separated by 12.5% of sternal width, straight endopod lateral margin on pleopod 1, appendix masculina straight and 1.6 times as long as endopod, uropod apices deeply subequal bifid with lateral process prominent. Cirolana arafurae is similar to C. erodiae Bruce, 1986 , C. phangnga Rodcharoen, Bruce & Pholpunthin, 2016 , C. siamensis Rodcharoen, Bruce & Pholpunthin, 2016 and C. thailandica Rodcharoen, Bruce & Pholpunthin, 2016 . Cirolana erodiae differs by having a laterally bent inward appendix masculina (vs straight), more close set penial openings and shallow subequal bifid uropod apices (vs deeply subequal bifid). Males of Cirolana phangnga , C. siamensis and C. thailandica are all distinguished by having the setose fringe on the propodus–carpus only.

Yu & Li’s (2001, 2003) record of Cirolana arafurae from Hainan is not accepted here, and considered a misidentification for two reasons. Firstly, there is an inconsistency in several characters recorded for ‘ Cirolana arafurae ’ from Hainan in comparison to the original description and material from Indonesia: the presence of two horizontal lines on pereonite 1 (vs absent in C. arafurae s. str), sub-basal attachment of appendix masculina (vs basal in C. arafurae s. str), shorter appendix masculina (1.5 vs 1.6 times as long as endopod in C. arafurae s. str), 4 robust setae on endopod lateral margin (vs 2–3). Secondly, it is unlikely that the range of C. arafurae would extend from tropical and equatorial coral reefs in central and eastern Indonesia to a northern subtropical region like Hainan, China.

Distribution. Known from the Kei Islands ( Bruce 1986), Lombok and Raja Ampat, central and eastern Indonesia ( 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 2. Cirolana arafurae, ♂ (4.6 mm, MZB Cru. Iso 051) (A – E, G), ♂ (5.0 mm, MZB. Cru. Iso 054) (F, H – J): A, dorsal view; B, lateral view; C, frons; D, head; E, penial openings; F, uropod; G, pleon; H, antennula; I, antenna pedunCle; J, pleotelson.

FIGURE 3. Cirolana arafurae, ♂ (5.0 mm, MZB Cru. Iso 054): A, maxillula; B, maxilliped; C, maxilla; D, right mandible; E, pleopod 1; F, pleopod 2.

FIGURE 4. Cirolana arafurae, ♂ (5.0 mm, MZB Cru. Iso 054): A, pereopod 1; B, pereopod 2; C, pereopod 6; D, pereopod 7.