Metacirolana lombok Sidabalok & Bruce 2018, sp. nov.
Creators: name: Sidabalok, Conni M.
name: Bruce, Niel L.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Cirolanidae
Metacirolana
Metacirolana lombok

description: Metacirolana lombok sp. nov.
(Figs 1–4)
All Indonesia. Holotype: ♂ (2.2 mm), Teluk Mentigi, Lombok, 8°21'26.94''S, 116°07'19.32''E, 7 August 2014, 3 m, rubble and dead coral head, coll. C.M. Sidabalok and party (MZB Cru.Iso 076).
Paratypes: 7 ♂ (2.0, 2.0, 2.2, 2.4, 2.4 [dissected], 2.5, 2.6 mm), 17 ♀ (1.7–2.8 mm, [one 2.8 mm dissected], average = 2.2 mm), same data as holotype (MZB Cru.Iso 077). 5 ♀ (2.0, 2.1, 2.2, 2.2, 2.2 mm), same data as holotype (MTQ W34875). 6 ♀ (2.1, 2.1, 2.2, 2.3, 2.4, 2.6 mm), Gili Air, Lombok, 8°21'27.238''S, 116°05'17.206''E, 13 August 2014, 10 m, rubble and dead coral head, coll. C.M. Sidabalok and party (MZB Cru.Iso 078). 3 ♂ (2.1, 2.2, 2.2 mm), 16 ♀ (1.9–2.6 mm, average = 2.2 mm), Teluk Medana, Lombok, 8°21'34.00''S, 116°07'25.59''E, 14 August 2014, 6 m, rubble and dead coral head, coll. C.M. Sidabalok and party (MZB Cru.Iso 079). 16 ♀ (1.5–2.5 mm, average = 2.0 mm), Teluk Kodek, Lombok, 8°24'13.44''S, 116°04'19.02''E, 11 August 2014, hand collection on intertidal reef, coll. C.M. Sidabalok and party (MZB Cru.Iso 080).
Description. Body 2.7 times as long as greatest width, dorsal surfaces smooth, widest at pereonite 5, lateral margins subparallel. Rostral point present. Eyes separated by about 50% width of head, eye colour black. Pereonite 1 and coxae 2–3 each with posteroventral angle acute; coxae 5–7 with entire oblique carina; posterior margins of pereonites 4–7 smooth. Pleon with pleonite 1 visible in dorsal view, pleonites 3–5 posterior margin smooth; posterolateral angles of pleonite 2 forming acute point, pleonite 3 posterolateral margins not extending to posterior margin of pleonite 5, acute, pleonite 4 posterolateral margin acute, not extending beyond posterior margin of pleonite 5, pleonite 5 with posterolateral angles not overlapped by lateral margins of pleonite 4. Pleotelson 0.8 as long as anterior width; without longitudinal carina smooth, lateral margins straight, margins smooth, posterior margin truncate, with two small simple setae at median point, with 18 teeth.
Antennula peduncle article 2 1.7 as long as wide, 1.3 as long as article 1, 2.0 as long as combined articles 3 and 4; article 3 1.6 as long as wide; flagellum with 5 articles, extending to middle of pereonite 4. Antenna peduncle article 4 2.4 times as long as wide, 1.7 times as long as article 3, and 1 long simple seta and 1 pappose seta (distal); article 5 1.6 as long as article 4, 4.6 times as long as wide, anterodistal angle with cluster of 1 long simple seta and 2 pappose setae; flagellum with 10 articles, extending to posterior of pereonite 6.
Frontal lamina anteriorly rounded, margin weakly projecting, 2 times longer than greatest width, lateral margin concave narrowing strongly to posterior.
Mandible molar process anterior margin with 10 flat teeth; without proximal cluster of long simple setae; left mandible spine row composed of 10 spines; palp article 2 with 10 distolateral setae, palp article 3 with 7 robust biserrate. Maxillula mesial lobe with 3 CPS; lateral lobe with 9 RS. Maxilla lateral lobe with 3 long simple setae; middle lobe with 2 long simple setae; mesial lobe with 3 distal simple setae and 1 plumose. Maxilliped palp article 2 mesial margin with 2 slender setae, lateral margin distally with 1 slender seta; article 3 mesial margin with 4 slender setae, lateral margin with 2 slender setae; article 4 mesial margin with 4 slender setae, lateral margin with 1 slender seta; article 5 distal margin 4 setae, lateral margin with 1 seta; endite with 2 long CPS and 2 coupling setae.
Pereopod 1 basis 2.8 times as long as greatest width, superior distal angle without cluster of acute setae, inferior distal angle with 1 cluster of acute setae; ischium 0.6 times as long as basis, inferior margin without setae, inferior distal margin with 1 RS, superior distal margin with 1 long simple seta; merus inferior margin with 3 RS, inferior distal margin with 1 RS and 1 long simple seta, superior distal angle with 2 long simple setae; carpus inferior distal margin with 1 RS and 1 long simple seta; propodus 1.7 times as long as wide, inferior margin with 1 RS, inferior distal margin with 1 large RS and 3 simple setae, superior distal 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 acute RS, inferior distal margin with 1 RS and 1 long simple seta, superior distal margin with 1 long acute RS and 1 plumose seta; carpus inferior distal margin with 1 long acute RS and 3 long simple setae; propodus 2.1 as long as wide, with 1 cluster of acute RS, inferior margin with 1 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 similar to pereopod 7. Pereopod 7 basis 3.0 times as long as greatest width, superior margin convex with 1 palmate seta; ischium 0.7 as long as basis, inferior margin with 2 RS (set as 1 and 1), inferior distal angle with 2 RS, superior distal angle with 2 RS; merus 0.5 as long as ischium, 2.0 times as long as wide, inferior margin with 1 RS, superior distal angle with 4 RS (1 biserrate), inferior distal angle with 4 RS; carpus 0.8 as long as ischium, 3.2 times as long as wide, inferior margin with 1 RS, superior distal angle with 9 RS (8 biserrate), inferior distal angle with 5 RS (2 biserrate); propodus 0.9 as long as ischium, 5.2 times as long as wide, inferior margin with 1 cluster of RS, superior distal angle with 2 slender setae, 1 plumose seta and 1 RS, inferior distal angle with 3 RS; dactylus 0.5 as long as propodus.
Penes distinct flat lobes, separated by 4.6% of sternal width.
Pleopod 1 exopod 1.4 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 ~15 PMS; endopod 2.1 times as long as wide, distally narrowly rounded, lateral margin straight, with PMS from distal one-third, mesial margin with PMS from distal one-third, endopod with ~13 PMS; peduncle 0.6 times as wide as long, mesial margin with 3 coupling setae. Pleopod 2 exopod with ~18 PMS, endopod with ~13 PMS; appendix masculina subbasal, with parallel margins, as long as endopod, distally acute. Pleopod 3 exopod with ~21 PMS, endopod with ~11 PMS. Pleopod 4 exopod with ~18 PMS, endopod with ~9 PMS. Pleopod 5 exopod with ~7 PMS. Pleopods 2–5 peduncle distolateral margin with prominent acute RS.
Uropod peduncle ventrolateral margin with 2 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 deeply bifid, mesial process prominent; lateral margin distally convex, without prominent excision, distal lateral margin with 5 teeth; mesial margin strongly convex, with 10 teeth. Exopod not extending to end of endopod, 3.3 times as long as greatest width, apically deeply bifid, mesial process prominent; lateral margin convex, with 5 teeth; mesial margin convex, with 5 teeth.
Female. Of similar appearance to the male. No ovigerous female present.
Variation. Number of teeth on pleotelson varies between 10–18 (10 = 3.6%, 12 = 7.1%, 13 = 28.6%, 14 = 21.4%, 15 = 32.1%, 16 = 3.6%, 18 = 3.6%, n = 28). Number of teeth on uropod rami (n = 16): exopod lateral 4–5 (4 = 80%, 5 = 20%), exopod mesial 3–5 (3 = 18.8%, 4 = 75%, 5 = 6.2%), endopod lateral 4–5 (4 = 87.5%, 5 = 12.5%), endopod mesial 8–10 (8 = 68.8%, 9 = 18.7%, 10 = 12.5%).
Remarks. Metacirolana lombok sp. nov. is most similar to M. serrata and M. bastenae (Bruce, 1980b), sharing a weakly produced rostrum, anteriorly dilated frontal lamina, similarly shaped robust setae on inferodistal of propodus pereopod 1, close set penial processes (only M. serrata; males not known for M. bastenae), distally acute and abruptly narrower towards apex appendix masculina, mesial and lateral convex with apex bifid mesial prominent of uropod rami. Metacirolana lombok is also similar Metacirolana mioskon sp. nov., including body shape, rostral characters and pereopod morphology, but differs in having 2 coupling hooks on maxilliped endite (vs 1, which is also shared with M. serrata), more close set penial process (4.6% sternal width vs 20.5% in M. mioskon), less broad uropodal exopod (0.3 vs 0.5 WL). Metacirolana lombok differs to M. serrata in having antennule extending to middle of pereonite 4 (vs middle of pereonite 3), antennal flagellum extension to the posterior of pereonite 6 (vs posterior of pereonite 7), narrower pleotelson margin and more convex and angled mesial and lateral margins of uropodal endopod (120° vs 90°). Metacirolana lombok differs to M. bastenae in having less angular and truncate pleotelson (vs angled and truncate) and less broad uropodal rami, especially on the posterior of exopod (0.6 vs 0.8 endopod WL, 0.3 vs 0.7 exopod WL).
Distribution. Only known from Lombok, Indonesia.
Etymology. Named after the main island of the type locality.
description: Published as part of Sidabalok, Conni M. & Bruce, Niel L., 2018, Two new species and a new record of Metacirolana Kussakin, 1979 (Crustacea: Isopoda: Cirolanidae) from Indonesia, pp. 519-534 in Zootaxa 4370 (5) on pages 521-527, DOI: 10.11646/zootaxa.4370.5.4, http://zenodo.org/record/1147327