Lucayalana troglexuma (Botosaneanu & Iliffe, 1997) Botosaneanu & Iliffe, 1997

Bruce, Niel L., Brix, Saskia, Balfour, Nicholas, Kihara, Terue C., Weigand, Alexander M., Mehterian, Sevag & Iliffe, Thomas M., 2017, A new genus for Cirolanatroglexuma Botosaneanu & Iliffe, 1997, an anchialine cave dwelling cirolanid isopod (Crustacea, Isopoda, Cirolanidae) from the Bahamas, Subterranean Biology 21, pp. 57-92 : 65-68

Lucayalana troglexuma (Botosaneanu & Iliffe, 1997) comb. n.

Cirolana (Cirolana) troglexuma Botosaneanu & Iliffe, 1997: 79, figs 1 –24.– 1999: 96.

Cirolana (Cirolana) troglexuma . - Iliffe and Botosaneanu 2006: 15, plate 1b, fig. 19.

Type locality.

Oven Rock Cave, [Great Guana Cay] Exuma Cays, The Bahamas; habitat is anchialine.

Material examined.

Holotype ♀ (non-ovig. c. 10 mm - dissected, body in three pieces) Oven Rock Cave, Great Guana Cay, Exuma Cays, The Bahamas, 22 May 1995, depth 1-22 m, plankton net, coll. T.M Iliffe. (USNM 285818).

Non-type material: ♀ (non-ovig. 8.5 mm), Great Guana Cay, Exuma Cays, Bahamas; Oven Rock Cave, 31 March 1988, coll. TM Iliffe. (ZMA CRUS.I.204411). ♀ (non-ovig. 7.8 mm), Great Guana Cay, Exuma Cays, Bahamas; Oven Rock Cave, 14 August 2002, coll. TM Iliffe. (IRScNB-KBIN I.G. 29862; INV.112511). ♀ (non-ovig. 7.4 mm), manca (4.1 mm), Cat Island, Central Bahamas, Big Fountain Cave, 18 August 2004, coll. TM Iliffe. (ZMA CRUS.I.204653). 1 ♂ (6.9 mm), 28 ♀ (7.4-10.7 mm), Eleuthera, Bahamas; Hatchet Bay Cave, seaward cave entrance 25°21 ’59.9” N, 76°31 ’12.8” W, landward entrance at 25°21 ’56.5” N, 76° 31' 20.8"W, November 2014, coll. N Balfour (ZMH K45768-45777 (♂ K45769); QM W34360).

Also examined. Cirolana willeyi Stebbing, 1904: ♂ (7.8 mm), Sungei Mandai, Singapore, 01°26.094'N, 03°45.656'E, 26 October 2012, mangroves, coll. YL D Fautin and R Tan (QM unreg). Cirolana erodiae Bruce, 1986: ♂ (7.8 mm), Lizard Island, April 2008, coral rubble, coll. C. Glasby (QM W30557).

Description.

Body 2.2 times as long as greatest width, dorsal surfaces smooth, widest at pereonite 5, lateral margins weakly ovate. Rostral point absent. Pereonite 1 and coxae 2-3 each with posteroventral angle right-angled; coxae 5-7 with incomplete 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, not posteriorly produced; pleonite 3 with posterolateral margins extending clearly beyond posterior margin of pleonite 5, acute; clearly extending beyond posterior margin of pleonite 5, posterolateral margin of pleonite 4 acute. Pleotelson 0.75 times as long as anterior width, dorsal surface without longitudinal carina; lateral margins weakly convex, margins smooth, posterior margin sub-truncate, without median point, with 10 robust setae.

Antennula peduncle articles 1 and 2 distinct, articulated; article 2 0.9 times as long as article 1, articles 3 and 4 1.1 times as long as combined lengths of articles 1 and 2, article 3 3.5 times as long as wide; flagellum with 12 articles, extending to posterior of pereonite 1. Antenna peduncle article 4 2.3 times as long as wide, 2.3 times as long as article 3, inferior margin with 0 plumose setae, and 2 short simple setae; article 5 1.4 times as long as article 4, 4.5 times as long as wide, inferior margin with 2 pappose setae, anterodistal angle with cluster of 2 short simple setae (and 3 pappose setae); flagellum with 21 articles, extending to pereonite 5.

Frontal lamina lanceolate, 2.9 times as wide as long posterior width, lateral margins converging to anterior, anterior margin acute.

Mandible molar process with proximal cluster of long simple setae; right mandible spine row composed of 7 spines; mandible palp article 2 with 9 distolateral setae, mandible palp article 3 with 7 robust biserrate setae (in two groups). Maxillula mesial lobe with 3 large and circumplumose RS; lateral lobe with 13 RS. Maxilla lateral lobe with 5 long simple setae; middle lobe with 14 long simple setae (2 plumose); mesial lobe with 5 distal simple setae, with 6 proximal simple and plumose setae. Maxilliped palp article 2 mesial margin with 5 slender setae, lateral margin distally with 2 slender setae; article 3 mesial margin with 10 slender setae, lateral margin with 6 slender setae; article 4 mesial margin with 12 slender setae, lateral margin with 4 slender setae; article 5 distal margin 18 setae, lateral margin with 3 setae; endite with 4 long CPS, and 2 coupling setae.

Pereopod 1 basis 2.4 times as long as greatest width, superior distal angle with cluster of 1 acute setae; ischium 0.5 times as long as basis, inferior margin with 2 setae, superior distal margin with 1 RS; merus inferior margin with 5 acute RS, set as two rows, superior distal angle with 1 setae; carpus inferior margin with 2 RS; propodus 2.6 times as long as wide, inferior margin with 4 RS; dactylus 0.6 as long as propodus, with bifid secondary unguis; inferior margin with setal fringe lacking. Pereopod 2 ischium inferior margin with 4 stout, acute RS, superior distal margin with 1 RS (large); merus inferior margin with 12 stout acute RS, set as two rows, superior distal margin with 4 acute RS; carpus inferodistal angle with 5 RS (2 serrate, 2 simple); propodus 4.1 as long as wide, with 3 RS; dactylus 0.4 as long as propodus. Pereopod 3 similar to pereopod 2. Pereopod 6 similar to pereopod 7. Pereopod 7 basis 2.9 times as long as greatest width, superior margin weakly convex, inferior margin with 2 palmate setae; ischium 0.4 as long as basis, inferior margin with 2 RS, superior distal angle with 2 RS, inferior distal angle with 4 RS; merus 1 as long as ischium, 2.1 times as long as wide, inferior margin with 10 RS, superior distal angle with 8 RS, inferior distal angle with 7 RS; carpus 0.8 as long as ischium, 2.1 times as long as wide, inferior margin with 0 RS, superior distal angle with 0 RS, inferior distal angle with 5 RS and 3 submarginal short RS; propodus 1.1 as long as ischium, 4.3 times as long as wide, inferior margin with 3 single RS, superior distal angle with 2 and 1 palmate slender setae, inferior distal angle with 2 RS; dactylus 0.4 as long as propodus.

Pleopod 1 exopod 1.4 times as long as wide, lateral margin straight, distally broadly rounded, mesial margin strongly convex, with PMS from distal two-thirds, with ~19 PMS; endopod 2.1 times as long as wide, distally broadly rounded, lateral margin concave, with PMS on distal margin only, mesial margin with PMS on distal margin only, endopod with ~10 PMS; peduncle 1.7 times as wide as long; mesial margin with 5 coupling setae. Pleopod 2 exopod with ~29 PMS, endopod with ~13 PMS. Pleopod 3 exopod with ~38 PMS, endopod with ~13 PMS. Pleopod 4 exopod with ~38 PMS, endopod with ~8 PMS. Pleopod 5 exopod with ~36 PMS. Pleopods 2-5 peduncle distolateral margin with prominent acute RS, 3-5 endopods without distomesial serrate scales.

Uropod peduncle ventrolateral margin with 3 RS, lateral margin with medial short acute RS, posterior lobe about one-half as long as endopod; rami extending beyond pleotelson, marginal setae in single tier, apices acute. Endopod apically not bifid; lateral margin weakly convex, proximal lateral margin with 1 RS; distal lateral margin with 2 RS, mesial margin weakly convex, with 8 RS. Exopod not extending to end of endopod, 3.1 times as long as greatest width, apically not bifid; lateral margin weakly convex, with 6 RS; mesial margin convex, with 5 RS.

Male.

Similar to female but for sexual characters. Appendix masculina 1.7 times as long as endopod, 17.0 times as along as proximal width, apex with short acuminate tip. Penial processes separated by 20% width of sternite, flat quadrate lobes, width 1.04 length.

Variation.

Many specimens had the robust setae missing, so precise counts could not be obtained from all specimens. The number of marginal robust setae on the pleotelson (n=12) ranges from 6 to 10, with 8 (42%) or 9 (25%) being most frequent. Uropodal exopod later margin robust setae (n=20): 5-7, with 5 (55%) and 6 (most frequent 40%), 7 once; mesial margin robust setae (n=21) with 4-7, with 6 (52%) and 5 (43%) most frequent. ++ later margin robust setae (n=18): 1+1 (33%) or 2+1 (77%); mesial margin with 6-16 robust setae (n=24), with only 6 (17%) and 9 (21%) occurring more than twice. These data are from the Eleuthera series, specimens from the Exuma Cays all fall within this range.

The range of variation in the robust setae of the uropodal endopod mesial margin is unusual within the family. Also unusual is the difference in the shape of the pleotelson posterior margin, for the most being subtruncate with the uropodal rami extending beyond the posterior margin of the pleotelson (e.g. Figures 4A, 5A) except for the single male that has angled posterior margins with a clear median point of inflection with the uropodal rami extending to but not beyond the posterior pleotelson margin (Figure 7A). Sexual dimorphism is present in several genera of Cirolanidae , usually in the pleotelson and uropodal rami. Mature males of species of Cirolana in the so-called "tuberculate group" (see Bruce 1986) may have a differently shaped pleotelson and uropodal rami with more setae, than do the females. Such species include Cirolana comata Keable, 2001, Cirolana pleonastica Stebbing, 1900 (see Bruce 1994) and Cirolana wongat Bruce, 1994. Mature males of several species of the Cirolana " parva -group" have a dense setose fringe on the inferior margin of pereopod 1 that is absent in females.

Remarks.

The species can be identified by the generic characters, the small and anteriorly acute frontal lamina together with the pleonite morphology, notably the ventral expansion of the lateral margin of pleonite 2, distinguishing the species from all other cave cirolanids in the region. Molecular identification is possible using the species DNA barcodes.

Distribution.

Previous records are from anchialine caves on Great Exuma Island (Oven Rock Cave), Cat Island, Grand Guana Cay (one of the Exuma Cays) and Eleuthera; all are on the Great Bahama Bank, a shallow water platform surrounded on all sides by deep ocean waters.