Cirolana lembeh, Sidabalok & Bruce, 2018

Sidabalok, Conni M. & Bruce, Niel L., 2018, Review of the Cirolana ‘ pleonastica-group’ (Crustacea: Isopoda: Cirolanidae) with description of four new species from the Indo- Malaysian region, Raffles Bulletin of Zoology 66, pp. 177-207 : 197-201

Cirolana lembeh , new species

( Figs. 13–16 )

Material examined. All Indonesia. Holotype, male (4.8 mm) ( MZB Cru.Iso 094), Lembeh Strait, Bitung , North Sulawesi,

01°27′31.7′N, 125°14′02.2′E, trap 60 m, coll. B. Hermanto and C. Sidabalok, 24 July 2014.

Paratypes. 2 males (4.9 [dissected], 5.2 mm), 1 female (6.3 mm [dissected]) ( MZB Cru.Iso 095), same data as holotype ; 2 males (4.8, 4.9 mm) ( MTQ W34886), same data as holotype .

Description. Body 3.0 ( Fig. 13A ) times as long as greatest width, dorsal surfaces punctate, widest at pereonite 5, lateral margins subparallel. Rostral point absent. Eyes ( Fig. 13E ) separated by about 75% width of head, eye colour black. Pereonite 1 and coxae 2–3 ( Fig. 13B ) each with posteroventral angle rounded; coxae 5–7 with entire oblique carina; posterior margins of pereonites 5–7 without irregular submarginal nodules. Pleon ( Fig. 14E ) with pleonite 1 largely concealed by pereonite 7; pleonites 3–5 posterior margin with regular nodules; posterolateral angles of pleonite 2 forming acute point, extending posteriorly to anterior of pleonite 3; pleonite 3 without median tubercle and 2 sublateral tubercles on each side, posterolateral margins not extending to posterior margin of pleonite 5, acute; pleonite 4 without median tubercle and 4 sublateral tubercles on each side, posterolateral margin of pleonite 4 rounded, clearly extending beyond posterior margin of pleonite 5; pleonite 5 without median tubercle and 2 sublateral tubercles on each side and posterolateral angles overlapped by lateral margins of pleonite 4. Pleotelson ( Fig. 14F ) 0.7 times as long as anterior width; with a median row of fine setae; lateral margins straight, slightly convex towards posterior, margins smooth, posterior margin subtruncate, without median point, with 6 robust setae.

Antennula ( Fig. 13C ) peduncle articles 1 and 2 fused (suture present); articles 3 and 4 0.7 times as long as combined lengths of articles 1 and 2, article 3 1.4 times as long as wide; flagellum with 9 articles, extending to anterior of pereonite 1. Antenna ( Fig. 13D ) peduncle article 4 2.4 times as long as wide, 1.7 times as long as article 3, and 2 short simple setae and 1 palmate seta (distal); article 5 as long as article 4, 2.6 times as long as wide, anterodistal angle with cluster of 2 short simple and 2 palmate setae; flagellum with 18 articles, extending to posterior of pereonite 4.

Frontal lamina ( Fig. 13F ) pentagonal, 2.0 longer than greatest width, lateral margins straight, diverging slightly towards anterior, anterior margin concave and acute, forming median point.

Mandible ( Fig. 14A ) molar process anterior margin with 15 flat teeth; with proximal cluster of long simple setae; right mandible spine row composed of 6 spines; palp article 2 with 10 distolateral setae, palp article 3 with 14 plumose setae. Maxillule ( Fig. 14B ) mesial lobe with 3 large and circumplumose RS; lateral lobe with 12 RS. Maxilla ( Fig. 14C ) lateral lobe with 4 long simple setae; middle lobe with 11 long simple setae; mesial lobe with 4 distal simple setae, proximally with 5 proximal simple and plumose setae. Maxilliped ( Fig. 14D ) palp article 2 mesial margin with 4 slender setae, lateral margin distally with 1 slender seta; article 3 mesial margin with 12 slender setae, lateral margin with 4 slender setae; article 4 mesial margin with 11 slender setae, lateral margin with 4 slender setae; article 5 distal margin 17 setae, lateral margin with 5 setae; endite with 3 long CPS, and 2 coupling setae.

Pereopod 1 ( Fig. 15A ) basis 2.3 times as long as greatest width, superior distal angle without cluster of acute setae, inferior distal angle with cluster of 2 acute setae; ischium 0.5 times as long as basis, inferior margin with 3 setae, inferior distal margin with 1 RS, superior distal margin with 2 RS; merus inferior margin with 5 molariform RS, set as 2 and 3, with 3 simple setae, inferior distal margin with 1 RS, superior distal angle with 1 RS; carpus inferior margin with 1 RS and 1 simple seta; propodus 2.1 times as long as wide, inferior margin with 3 RS, inferior distal margin with 2 large RS and 4 simple setae, superior distal with 4 simple setae; dactylus 0.8 as long as propodus. Pereopod 2 ( Fig. 15B ) ischium inferior margin with 2 simple setae, inferior distal margin with 2 RS, superior distal margin with 2 long acute setae; merus inferior margin with 3 stout RS and 1 RS, set as single row, inferior distal margin with 1stout RS and 1 acute RS, superior distal margin with 2 long acute RS; carpus inferior distal margin with 3 acute RS and 1 long simple seta; propodus 3.3 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 0.8 as long as propodus. Pereopod 3 similar to pereopod 2. Pereopod 6 ( Fig. 15C ) similar to pereopod 7. Pereopod 7 ( Fig. 15D ) basis 2.4 times as long as greatest width, superior margin straight with 1 palmate seta; ischium 0.5 as long as basis, inferior margin with 4 RS (set in group of 2 and 2), inferior distal angle with 2 RS (1 blunt), superior distal angle with 6 RS (3 biserrate); merus as long as ischium, 2.2 times as long as wide, inferior margin with 3 RS, superior distal angle with 6 RS (2 biserrate), inferior distal angle with 4 RS; carpus 0.9 as long as ischium, 2.3 times as long as wide, inferior margin with 2 RS, superior distal angle with 8 RS (4 biserrate), inferior distal angle with 8 RS (2 biserrate); propodus as long as ischium, 4 times as long as wide, inferior margin with 2 clusters of RS (set as 2 and 1), 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 ( Fig. 13G ) opening flush, penial openings separated by 19% of sternal width.

Pleopod 1 ( Fig. 16A ) exopod 1.3 times as long as wide, lateral margin straight, distally broadly rounded, mesial margin strongly convex, with PMS from distal one-third, with ~25 PMS; endopod 1.9 times as long as wide, distally broadly rounded, lateral margin straight and proximal weakly convex, with PMS from distal one-third, mesial margin with PMS on distal margin only, endopod with ~12 PMS; peduncle 1.4 times as wide as long. Pleopod 2 ( Fig. 16B ) exopod with ~31 PMS, endopod with ~12 PMS; appendix masculina with parallel margins, as long as endopod, distally acute. Pleopod 3 ( Fig. 16C ) exopod with ~38 PMS, endopod with ~11 PMS. Pleopod 4 ( Fig. 16D ) exopod with ~36 PMS, endopod with ~10 PMS. Pleopod 5 ( Fig. 16E ) exopod with ~42 PMS. Pleopods 2–5 peduncle distolateral margin with prominent acute RS, 3–5 endopods with distomesial serrate scales.

Uropod ( Fig. 13H–13I ) peduncle ventrolateral margin with 2 RS, lateral margin with medial short acute RS, posterior lobe about as long as endopod; rami extending beyond pleotelson, marginal setae in three tiers, apices not bifid. Endopod apically narrowly rounded; lateral margin weakly convex, proximal lateral margin with 1 RS; distal lateral margin with 1 RS, mesial margin convex, with 4 RS. Exopod as long as endopod both in male and female, 2.8 (2.9 in female) times as long as greatest width, apically not bifid; lateral margin straight with setal fringe on the posterior, with 5 visible widely separated RS; mesial margin convex, with 3 RS (female).

Female. Female differs with male in having two submedian tubercles rows on dorsal surface (3 tubercles each) (vs. a median row of fine setae) and 8 RS (vs. 6 RS) of the pleotelson ( Fig. 14G ). The exopod lacks the dense setal fringe on the posterior lateral margin and has a more convex lateral margin and less convex mesial margin (with the similar LW proportion), while the endopod mesial margin is more convex.

Size. Males 4.8–5.2 mm, mean 4.9 mm (n=5); non-ovigerous female 6.3 mm (n=1); all from type series.

Variation. RS count was measured from all type series (n=6). Uropod exopod lateral: 4 = 16.7%, 5 = 83.3%; mesial: 3 = 100% (n= 1 female, cannot be observed from males). Uropod endopod lateral: 2 = 83.3%, 3 = 16.7%; mesial: 4 = 66.7%, 5 = 33.3%. Pleotelson: 6 = 83.3%, 8 = 16.7%.

Remarks. The defining characters of Cirolana lembeh , new species, are the lack of submarginal nodules on the posterior of pereonite 6, the submedian row of fine setae on dorsal surface of pleotelson, and in the male the large mass of setae on the mesial margin of the uropodal exopod; the penial openings are notably wide apart, separated by 19% sternal width. Similar pattern on male pleotelson is also found in C. curtensis Bruce, 1986 . Distribution. Lembeh Strait, Bitung , North Sulawesi, Indonesia.

Etymology. Named for the type locality; noun in apposition.

Figures

Fig. 13. Cirolana lembeh n. sp. A–B, E–G, holotype male (4.8 mm) (MZB Cru.Iso 094), Bitung, Indonesia. C, D, I, paratype male (4.9 mm) (MZB Cru.Iso 095), Bitung, Indonesia. H, paratype female (6.3 mm) (MZB Cru.Iso 095). A, dorsal view; B, lateral view; C, antennula; D, antenna peduncle; E, head; F, frontal lamina; G, penial openings; H; uropod female; I, uropod male.

Fig. 14. Cirolana lembeh n. sp. A–F, paratype male (4.9 mm) (MZB Cru.Iso 095), Bitung, Indonesia. G, paratype female (6.3 mm) (MZB Cru.Iso 095). A, right mandible; B, maxillule; C, maxilla; D, maxilliped; E, pleon; F, pleotelson male; G, pleotelson female.

Fig. 15. Cirolana lembeh n. sp. A–D, paratype male (4.9 mm) (MZB Cru.Iso 095), Bitung, Indonesia. A, pereopod 1; B, pereopod 2; C, pereopod 6; D, pereopod 7.

Fig. 16. Cirolana lembeh n. sp. A–E, paratype male (4.9 mm) (MZB Cru.Iso 095), Bitung, Indonesia. A, pleopod 1; B, pleopod 2; C, pleopod 3; D, pleopod 4; E, pleopod 5.