Leucosia singaporensis, H.-L. & Ng, 2003

H. - L., Chen & Ng, Peter K. L., 2003, On New Species Of Leucosiidae (Crustacea: Decapoda: Brachyura) From Singapore And The South China Sea, Raffles Bulletin of Zoology 51 (1), pp. 61-69 : 67-69

Leucosia singaporensis , new species

( Figs. 1G, H , 5 )

Material examined. – Holotype - male (28.0 by 24.0 mm) ( ZRC 1965.10.13.49), Singapore, coll. 13 Oct.1965.

Paratype – 1 female (32.0 by 26.3 mm) ( ZRC 1965.10.13.50), same data as holotype .

Diagnosis. – Carapace rhomboidal, smooth (except dorsum which may be pitted); regions indistinct. Hepatic region weakly elevated, median portion very convex. Front slightly projected, with 3 teeth: median tooth longer than weak lateral teeth. Behind front, median line with longitudinal smooth ridge, lateral areas depressed. Anterolateral margin shorter than posterolateral margin, without granules, latter with fine granules. Posterior carapace margin convex medially, both sides slightly convex. Exopod of third maxilliped narrow, 3 times as long as broad; merus narrowly triangular, longer than ischium, female ischium with tooth subdistally, inner side with longitudinal row of setae which extends to base of merus, male ischium without tooth, glabrous. Male abdomen with 5 free segments; segments 3-5 fused, basal half with shallow median groove, both sides strongly convex, median part of distal half convex, sides depressed; segment 1 very narrow transversely; segment 2 very narrow transversely, segment 6 1.4 times as long as broad, median part of basal one-third with small dent; telson triangular. Female abdomen longitudinally ovate, elevated medially, with 4 free segments (segments 3-6 fused), median portion of segments 1 and 2 convex posteriorly; telson slightly longer than broad, distal end bluntly rounded. G1 stout, long, distal part broadly membranous, surrounded by long setae, with hook-like process curving inwards.

Etymology. – The species is named after its type locality, Singapore.

Remarks. – This new species closely resembles Leucosia magna Tyndale-Biscoe & George, 1962 , and Leucosia major , new species, in the shape of the carapace and form of the thoracic sinus. The differences between these three species are summarised in Table 1.

Figures

Fig. 1. A, Heteronucia margaritata, new species: holotype male (3.0 by 3.5mm) (ZRC 1993.263); B, Pseudophilyra punctulata, new species: paratype female (6.0 by 5.4 mm) (ZRC 1995.550); C-F, Leucosia major, new species, C: holotype male (38.0 by 34.0mm) (ZRC 1984.50), D, paratype male (37.1 by 32.0 mm) (ZRC 1984.6325), E, F, paratype female (36.0 by 31.9 mm) (ZRC 1984.6326); G, H, Leucosia singaporensis, new species: holotype male (28.0 by 24.0 mm) (ZRC 1965.10.13.49). A-C, E, G = dorsal views; D, F, H = ventral views.

Fig. 5. Leucosia singaporensis, new species. A, B, D, H-J, holotype male (28.0 by 24.0 mm) (ZRC); C, E-G, K, paratype female (32.0 by 26.3 mm) (ZRC). A, carapace; B, right cheliped; C, third and fourth ambulatory legs (top to bottom); D, thoracic sinus; E, third maxillipeds; F, female abdomen; G, female telson; H, male abdomen; I, G1; J, distal part of G1; K, female genital opening. Scales = 0.5 mm.