Coleusia huilianae, Promdam, Rueangrit, Nabhitabhata, Jaruwat & Galil, Bella S., 2014

Promdam, Rueangrit, Nabhitabhata, Jaruwat & Galil, Bella S., 2014, A new species of Coleusia Galil, 2006 (Decapoda: Brachyura: Leucosiidae) from southern Asia, Zootaxa 3786 (2), pp. 135-140 : 136-140

Coleusia huilianae n. sp.

( Figs. 1–4 )

Leucosia urania, Alcock 1896: 220 .— Ihle 1918: 316 (part) (not Cancer urania Herbst, 1801 ). Leucosia grandis, Chen & Türkay , in Chen & Sun, 2002 (part).

Not Leucosides urania or Leucosia urania, Rathbun 1910: 309 , pl. 1, fig. 1.— Naiyanetr 1998: 58 (in list); 2007: 69 (in list) (= Soceulia brunnea (Miers, 1877)) .

Material examined. Thailand (Gulf of Thailand). Holotype. Ko Raet, Sattahip, Chon Buri Province, 18.05.2012, leg. P. Wisespongpand, 1 ♂ (35.3 mm) (PSUNHM 211514-333-0041). Paratypes. Ko Phai, Ko Rin and Ko Khram, Artisanal fishery of Ko Lan, Chon Buri Province, bottom gill net, 19.10.2012, leg. P. Wisespongpand, 1 ♂ (38.5 mm) (KUMF-ART0012); Pattani Province, 25.07.1984, leg. Bencha Mapha, paratype of Leucosia grandis Chen & Tu ?rkay, 1 ♂ (37.2 mm) ( ZRC 2000.0094); Pattani fishing port, 25.10.1998, leg. H.H. Tan, 1 ♂ (37.2 mm) ( ZRC 1999.0304); 0 6.2011, leg. P.K.L from aquarium dealer in Bangkok. Ng, 1 ♂ (37.2 mm) ( ZRC 2011.0662).

Additional material: India. Dhanushkodi, Rameshwaram, discards on shore, 31.07.2009, leg. V.S. Kakati, 1 ♂ (35.5 mm) ( CMFRI ED.5.6.4.1), 1♀ (34.2 mm) ( CMFRI).

Singapore. 1983, 1 ♂ (35.5 mm) ( ZRC 1988.2237).

Description. Carapace ( Figs. 1 , 2 ) subpentagonal, globose, 1.1 times as long as wide; dorsal surface glabrous, smooth, sparsely punctate; regions indistinct. Frontal region produced, upcurved, deeply concave medially, laterally constricted; frontal margin rounded. Anterolateral surface slightly inflated anteriorly, margin sinuous, with obsolescent granules distally. Lateral angle of carapace rounded, overhanging thoracic sinus, margin prominently beaded, granules lozenge-shaped. Posterolateral margins of carapace rounded, smooth. Epimeral margin invisible in dorsal view, gutter-like anteriorly, narrowing posteriorly, closely beaded marginal granules decreasing in size posteriorly, meeting posterior margin at an angle. Posterior margin sinuous in male, slightly rounded in female, minutely granular; deflexed posterior surface smooth.

Antennule obliquely folded into fossa, fossa sealed by basal antennular segment. Antennae short, inserted between antennular fossa, orbit. Orbits small, rounded, outer orbital margin unisutured, anterior margin of efferent branchial channel forms part of lower orbital margin. Eyes retractable. External maxillipeds concealing trapezoid buccal opening, smooth; endopod merus triangulate, as long as ischium; in female, endopod with setose fringe lengthwise, ischium medially elevated, keel-like. Thoracic sinus deep, tomentose, anterior margin level with base of coxopodite of third maxillipeds, anteriorly defined by overhanging beaded margin of pterygostomian region; ventral margin with row of oval granules medially, decreasing in size posteriorly ( Fig. 2 B). Thoracic sternites smooth, shiny; sternites 1–4 fused; sternites 4–8 with medially interrupted sutures between them. Abdominal cavity nearly reaching buccal cavity, lateral margins prominently ridged medially, ridge fitting into notch between somites 5, 6. Male abdomen smooth; somite 1 transversely narrow; somite 2 narrow, spindle-shaped; somites 3–6 fused, proximally inflated, furrowed lengthwise; somite 6 separated from proximal segments by suture, with lateral margins evenly curved, narrowing distally, with prominent triangular denticle on proximal quarter; telson triangular, as wide as long ( Fig. 2 F). Female abdomen with somites 3–6 fused, greatly enlarged, shield-like, telson triangular. First male gonopod elongated, shaft stout, sinuous, tightly coiled 3 times on its axis, ultimate coil swollen, setose; apical process cornute, digitate, curved externally ( Figs. 3 , 4 ). Second male gonopod short, slender, apex scoop-like.

Chelipeds subequal, robust, longer in adult males than in females. Cheliped merus trigonal; anterior, posterior margins lined with perliform granules, diminishing in size distally on posterior margin, reaching two-thirds posterior margin ( Fig. 2 C); upper surface with coalesced cluster of granules proximally, followed by 4 large perliform granules, distally smooth; lower surface pitted, granular proximally, few small granules proximally on posterior margin. Carpus inflated, smooth. Propodus lenticular, slightly longer as wide, upper margin rounded, smooth; lower margin with row of minute granules, lower external surface minutely punctuate ( Fig. 2 D). Fingers as long as propodus, gaping, cutting edges, finely teethed. Ambulatory legs similar in shape, gradually decreasing in length from first to fourth. Coxal condyles rounded. Meri subcylindrical; meri 1-4 with row of minute granules on upper margin, obsolescent on anterior merus; curved row of granules on lower margin, last merus with prominently granular crest proximally. Carpi rounded, obsolescent denticle on upper surface. Propodi dorsally, ventrally carinate, expanded, foliaceous ( Fig. 2 E). Dactyli longer than propodi, lanceolate.

Etymology. The name honours a fellow carcinologist, the late Chen Hui Lian of the Institute of Oceanology, Chinese Academy of Science in Qingdao, China, who had published extensively on leucosiid crabs.

Remarks. Alcock (1896: 220) listed a single female specimen of Leucosia urania collected in the Andaman Is. Its size (38 mm), foliaceous meropodites and color pattern fit Coleusia huilianae n. sp. Rathbun (1910: 309) identified material collected by the Danish Expedition to Siam from the islands of Koh Chang, Koh Lan and Koh Kahdat as Leucosides urania . Upon examination, however, her specimens were identified as Soceulia brunnea (Miers, 1877) ( Galil, 2006b) . Ihle (1918: 316) listed L. urania among the Indo-West Pacific leucosiids and cited the records by Alcock and Rathbun. Naiyanetr (1998, 2007) listed L. urania in Thailand, citing the localities cited by Rathbun, and doubtlessly referring to her misidentified material.

Coleusia huilianae n. sp., like the closely allied C. urania (Herbst, 1801) , differs from their cogeners in having prominently granular pereiopodal meri and expanded, leaf-like pereiopodal propodi. Coleusia huilianae n. sp. and C. urania have a superficially similar colour pattern consisting of a broad pale stripe medially on the carapace, two large rust-colored blotches posteriorly, and two smaller blotches on the posterolateral margins. The new species differs from C. urania , however, in the shape of the apical process of the first male pleopod which is digitate and curved laterally in the former, beak-like and curved interiorly in the latter; granulation on the posterior and lower margins of cheliped and ambulatory meri smaller and sparser, and entirely missing from lower external surface of the palm.

Distribution. India (Tamil Nadu and Andaman Is.), Gulf of Thailand, Singapore.

Colour ( Fig. 1 ). Dorsal surface of carapace olive green, paler laterally and posteriorly; a whitish stripe proceeding from the front to the gastric region. Two large rust coloured spots on the posterior part of the carapace, two smaller spots near lateral margin above first ambulatory leg. The anterior margins of the thoracic sinus, the basal portion of the fingers, and a ring on each segment of the ambulatory legs, are all bright orange colored. Ventral surface paler grey.

Figures

FIGURE 1. Coleusia huilianae n. sp., paratype male (carapace length 37.2 mm, carapace width 33.3) (ZRC 2000.0094). Dorsal view of carapace, colours in life.

FIGURE 2. Coleusia huilianae n. sp., Holotype male (carapace length 35.3 mm, carapace width 32.6) (PSUNHM 211514 - 333 - 0041). A, dorsal view; B, lateral view of carapace showing thoracic sinus; C, outer view of left merus of cheliped; D, view of lower margin of palm; E, fourth ambulatory leg; F, ventral view of cephalothorax.

FIGURE 3. Left male first gonopod of Coleusia huilianae n. sp., paratype male (carapace length 37.2 mm, carapace width 33.3) (ZRC 2000.0094). A, dorsal view; B, ventral view.

FIGURE 4. Left male first gonopod of Coleusia huilianae n. sp., paratype male (carapace length 37.2 mm, carapace width 33.3) (ZRC 2000.0094), setae denuded. Scales: A = 3.0 mm; B, C = 1.0 mm.