Cirolana bambang, Sidabalok & Bruce, 2018

Sidabalok, Conni M. & Bruce, Niel L., 2018, Cirolana bambang, a distinctive new species of Cirolana Leach, 1818 (Crustacea: Isopoda: Cirolanidae) from Bitung, Indonesia, Zootaxa 4375 (3), pp. 441-450 : 442-448

Cirolana bambang sp. nov.

( Figs. 1–4 )

Material examined. All North Sulawesi, Indonesia.

Holotype. ♂ (7.4 mm), Mawali, Bitung, 01°26'53.6''N, 125°14'17.3''E, 23 July 2014, trap 20 m, coll. B. Hermanto and C. Sidabalok (MZB Cru.Iso 073).

Paratypes. 2 ♂ (6.0, 6.5 [dissected] mm), 5 ♀ (5.0, 6.5, 7.4, 8.0, 8.8 mm), eastern Sarena Island , Bitung, 01°27'34.4''N, 125°13'59.0''E, 18 July 2014, trap 50 m, coll. B. Hermanto and C. Sidabalok ( MZB Cru.Iso 074) . 1 ♀ (5.0 mm), same data as above (MTQ W34873) . 1 ♂ (7.9 mm), Sarena Island , Bitung, 01°27'38.8''N, 125°13'51.6''E, 17 July 2014, trap 20 m, coll. B. Hermanto and C. Sidabalok ( MZB Cru.Iso 075) . 1 ♂ (6.0 mm), same data as above (MTQ W34873) . 1 ♀ (8.4 mm), Mawali, Bitung, 01°26'53.6''N, 125°14'17.3''E, 23 July 2014, trap 40 m, coll. B. Hermanto and C. Sidabalok (MTQ W34874).

Description based on male. Body 3.3 times as long as greatest width, dorsal surfaces smooth, widest at pereonite 5, lateral margins subparallel. Rostral point absent. Eyes separated by about 84% 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 2–3 posterior margin smooth, pleonite 4 with 6 submedian nodules, pleonite 5 with 2 submedian posterior nodules and 4 submedian anterior nodules; posterolateral angles of pleonite 2 forming acute point, not posteriorly produced, pleonite 3 posterolateral margins not extending to posterior margin of pleonite 5, acute, pleonite 4 posterolateral margin rounded not extended beyond posterior margin of pleonite 5, pleonite 5 with posterolateral angles overlapped by lateral margins of pleonite 4. Pleotelson as long as anterior width; without longitudinal carina; with dense patch of setae; lateral margins straight, smooth; posterior margin narrowly rounded, with small distinct median point, with 6 robust setae.

Antennula peduncle articles 1 and 2 distinct, articulated, article 2 0.7 as long as article 1, articles 3 and 4 0.8 times as long as combined lengths of articles 1 and 2, article 3 1.8 times as long as wide; flagellum with 12 articles, extending to posterior margin of eye. Antenna peduncle article 4 2 times as long as wide, 1.7 times as long as article 3, with 2 short simple setae (distal); article 5 1.2 as long as article 4, 2.3 times as long as wide, anterodistal angle with cluster of 1 short simple seta, 2 long simple setae and 2 pappose setae; flagellum with 29 articles, extending to pereonite 5.

Frontal lamina pentagonal, ventral surface entirely flat, 2 times longer than greatest width, lateral margins straight and parallel, anterior margin concave and acute, forming median point.

Mandible molar process anterior margin with 21 flat teeth; with proximal cluster of long simple setae; right mandible spine row composed of 7 spines; palp article 2 with 9 distolateral setae, article 3 with 3 robust biserrate and 16 plumose setae. Maxillula mesial lobe with 3 large circumplumose RS; lateral lobe with 9 RS. Maxilla lateral lobe with 4 long simple setae; middle lobe with 12 long simple setae; mesial lobe with 7 distal simple setae, proximally with 5 simple and plumose setae. Maxilliped palp article 2 mesial margin with 5 slender setae, lateral margin distally with 1 slender seta; article 3 mesial margin with 9 slender setae, lateral margin with 7 slender setae; article 4 mesial margin with 9 slender setae, lateral margin with 5 slender setae; article 5 distal margin with 16 setae, lateral margin with 9 setae; endite with 5 long CPS and 2 coupling setae.

Pereopod 1 basis 2.1 times as long as greatest width, superior distal angle with 1 cluster of acute setae, inferior distal angle without cluster of acute setae; ischium 0.7 times as long as basis, inferior margin with 2 simple setae and 1 RS, inferior distal margin with 1 RS, superior distal margin with 1 large massive RS; merus inferior margin with 3 molariform RS, set as single row (1 and 2), with 2 simple setae, inferior distal margin with 1 RS, superior distal angle with 3 long simple setae; carpus inferior margin with 2 RS and 1 simple seta; propodus 2.1 times as long as wide, inferior margin with 2 RS, inferior distal margin with 1 large RS and 3 simple setae, superior distal margin with 2 simple setae; dactylus 0.7 as long as propodus. Pereopod 2 ischium inferior margin with 2 long simple setae, inferior distal margin with 1 RS, superior distal margin with 1 long acute seta; merus inferior margin with 2 stout RS and 2 acute RS, set as single row, inferior distal margin with 4 stout RS and 1 long simple seta, superior distal margin with 4 long acute RS; carpus inferior distal margin with 3 long acute RS and 1 long simple seta; propodus 2.8 as long as wide, with 2 clusters of acute RS, inferior margin with 2 RS, inferior distal margin with 1 large RS and 1 simple seta; dactylus 0.7 as long as propodus. Pereopod 3 similar to pereopod 2. Pereopod 6 similar to pereopod 7 except for the presence of a large robust seta on the posterodistal angle of the basis which also occurs on pereopods 4–5. Pereopod 7 basis 2.3 times as long as greatest width, superior margin convex with 2 palmate setae; ischium 0.6 as long as basis, inferior margin with 4 RS (set as 3 and 1), inferior distal angle with 2 RS, superior distal angle with 4 biserrate RS; merus 0.7 as long as ischium, 1.6 times as long as wide, inferior margin with 1 RS, superior distal angle with 8 biserrate RS, inferior distal angle with 5 RS; carpus 0.9 as long as ischium, 1.9 times as long as wide, inferior margin with 2 RS, superior distal angle with 8 biserrate RS, inferior distal angle with 5 RS (2 biserrate); propodus 0.9 as long as ischium, 4.1 times as long as wide, inferior margin with 2 clusters of RS (set as 1 and 2), superior distal angle with 1 slender seta, 1 plumose seta and 2 RS, inferior distal angle with 2 RS; dactylus 0.5 as long as propodus.

Penes distinct flat lobes, separated by 11.6% of sternal width.

Pleopod 1 exopod 1.6 times as long as wide, lateral margin straight, distally narrowly rounded with strongly oblique medial margin, mesial margin strongly convex, with PMS from distal one-third, with ~30 PMS; endopod 2.0 times as long as wide, distally narrowly rounded, lateral margin straight, with PMS from distal one-third, mesial margin with PMS on distal margin only, endopod with ~16 PMS; peduncle 0.6 times as wide as long, mesial margin with 4 coupling setae. Pleopod 2 exopod with ~39 PMS, endopod with ~17 PMS; appendix masculina basal attachment, with parallel margins, as long as endopod, distally acute. Pleopod 3 exopod with ~42 PMS, endopod with ~14 PMS. Pleopod 4 exopod with ~45 PMS, endopod with ~12 PMS. Pleopod 5 exopod with ~44 PMS. Pleopods 2–5 peduncle distolateral margin with prominent acute RS, 3–5 endopods with distomesial serrate scales.

Uropod peduncle ventrolateral margin with 1 RS, lateral margin with medial short acute RS, posterior lobe 0.9 as long as endopod; rami extending beyond pleotelson, marginal setae in single tier, apices acute. Endopod apically unequally bifid, lateral process prominent; lateral margin straight, without prominent excision, proximal lateral margin with 1 RS, distal lateral margin with 1 RS; mesial margin weakly convex, with 5 RS. Exopod not extending to end of endopod, 3.7 times as long as greatest width, apically unequally bifid, lateral process prominent; lateral margin weakly convex, with 5 RS; mesial margin convex, with 3 RS.

Female. Of similar appearance to the male but without the setae on the dorsal surface of the pleotelson.

Variation. The setae on the pleotelson are less dense in males at 6.0 mm (the smallest male size in the material) and it is expected the setae would be less or absent on individuals below that size. There is little variation in the number of robust setae on uropod and pleotelson (n = 10). Uropod exopod lateral margin with 5 = 100%, mesial margin with 3 = 100%; uropod endopod lateral margin with 2–3 (2 = 90%), mesial margin with 4–5 (5 = 90%); pleotelson with 6 and 8 (6 = 90%).

Remarks. Cirolana bambang sp. nov. is characterised by a smooth body with small, acute, submedian nodules on pleonites 4–5 and the anterior surface of the pleotelson together with a flat and pentagonal frontal lamina, linguiform pleotelson with setae over the dorsal surface (on males only), unequally bifid uropod apices, prominent flat penial processes, a conspicuously large robust seta on the superodistal angle of pereopod 1 ischium and also a large robust seta on the posterodistal angle of the basis of pereopods 4–6. Females may be identified without the presence of males by using the diagnostic characters other than the sexual characters.

Cirolana bambang sp. nov. does not belong in any of the larger recognised groups within the genus Cirolana , such as the Cirolana ‘ parva -group’ or the Cirolana ‘ pleonastica -group’ (see Sidabalok & Bruce 2017, 2018). Cirolana bambang is excluded from C. ‘ pleonastica -group’ as it has continuous robust and slender setae on the lateral margin of the uropodal exopod (versus widely spaced) and has smooth dorsal surfaces of the pereon (finely tuberculate only on the pleonites). Equally, it does not fit into the Cirolana ‘ parva -group’ as it lacks a rostral point (versus rostral point present and overlapping frontal lamina). Further distinguishing characters from both the Cirolana ’ parva -group’ and C. ‘pleonastica- group ’ are the large robust seta on the superodistal angle of pereopod 1 ischium, distinct flat penial processes [(versus opening flush to the sternite surface (small papillate openings in some of the Cirolana ‘ parva -group’)] and the presence of setae on the dorsal surface of the pleotelson in males (versus absence).

Nevertheless, Cirolana bambang shares certain characters with several species of Cirolana : the distinct flat penial lobes are shared with the following species: Cirolana meseda Hobbins & Jones, 1993 , which otherwise differs in the shape of uropod apices (deeply unequally bifid versus shallow bifid with both lateral prominent); C. mclaughlinae Bruce & Brandt, 2006 , which is different in having a posteriorly narrower pleotelson (versus linguiform) and nodules on all pleonites and pleotelson (versus only few on pleonite 4–5 and absent on the pleotelson) and C. kiliani Müller, 1993 , which has fine nodules on posterior margins of pleonites 4–5, the rostral point overlapping the frontal lamina and lacks setae on pleotelson dorsal surface.

The combination of the large robust seta on ischium of pereopod 1; dense setae on the dorsal surface of the pleotelson; and the small fine tubercles on the pleonites 4–5 and distinct flat penial lobes are also present in four other Cirolana species: Cirolana comata Keable, 2001 ; Cirolana dissimilis Keable, 2001 ; Cirolana aldabrensis Schotte & Kensley, 2005 and Cirolana somalia Schotte & Kensley, 2005 (the latter lacks the large seta on ischium of pereopod and only shows a produced distal of the ischium). Cirolana bambang shares the dense patch of setae restricted to the pleotelson of males only with C. dissimilis and C. aldabraensis . Cirolana meinerti Barnard, 1920 was described as having setae on the dorsal surface of the pleotelson, but the sole figure for the species is of the isolated frontal lamina so further comparison cannot be made. Males of Cirolana bambang and C. dissimilis both lack a setal brush on antenna flagellum, but that is present in C. comata . Further, Cirolana comata differs in having additional dense patch of setae on the uropodal endopod and exopod surfaces; more prominent tubercles on pereonite 4; and only 2 submedian tubercles on pereonite 5 (versus 4). While C. dissimilis has additional submedian tubercles on pleonite 3; more widely spaced tubercles on pleonite 4; and 2 submedian tubercles on pleonite 5 (versus 4). Furthermore Cirolana comata and C. dissimilis are unique from others by having prominent lateral tubercles on pleonite 5 of the males. The size of the large massive robust seta on ischium of pereopod 1also differs between the four species being largest in Cirolana bambang . Cirolana bambang and C. aldabrensis lack the tubercles between the eyes and on the dorsal surface of pereonite 1 which is present on other three species. Cirolana aldabrensis differs in having wider frontal lamina, a more pointed robust seta on ischium of pereopod 1, slightly longer appendix masculina than endopod (1.2 versus as long as endopod) and bifid uropod apices. See Table 1 for character comparisons between Cirolana bambang and the species above.

Cirolana bambang seems closest to C. comata , C. dissimilis and C. aldabraensis in having the dense patch of setae on the pleotelson, a large robust seta on the superodistal angle of pereopod 1 ischium and also a large robust seta on the posterodistal angle of the basis of pereopods 4–5 (4–6 in C. comata and C. bambang and no data for C. aldabraensis ).

Appraisal of the characters under discussion here (Table 1), notably the presence of prominent penial processes excludes Cirolana kiliani and Cirolana somalia from the Cirolana ‘ parva -group’ (see list in Rodchareon et al. 2016 and Sidabalok & Bruce 2017 for the exclusion of Cirolana aldabrensis and C. meseda ).

Distribution. Only known from Bitung, North Sulawesi, Indonesia; at depths of 20–50 metres.

Etymology. Named for LIPI scientist Mr Bambang Hermanto who greatly contributed in organising the field work, sampling activities and sample processing.

Figures

FIGURE 1. Cirolana bambang sp. nov., holotype ♂ (7.4 mm, MZB Cru.Iso 073) (A–C, E–G), paratype ♂ (6.5 mm, MZB Cru.Iso 074) (D, H, I, J): A, dorsalview; B, lateral view; C, frons;D, antenna pedunCle; E, head; F, pleon; G, penial proCess; H, uropod; I, pleotelson; J, antennula.

FIGURE 2. Cirolana bambang sp. nov., paratype ♂ (6.5 mm, MZB Cru.Iso 074) (A–D): A, right mandible; B, maxilla; C, maxillula; D, maxilliped.

FIGURE 3. Cirolana bambang sp. nov., paratype ♂ (6.5 mm, MZB Cru.Iso 074) (A–D): A, pereopod 1; B, pereopod 2; C, pereopod 6; D, pereopod 7.

FIGURE 4. Cirolana bambang sp. nov., paratype ♂ (6.5 mm, MZB Cru.Iso 074) (A–E): A, pleopod 1; B, pleopod 2; C, pleopod 3; D, pleopod4; E, pleopod 5.