Leucosia major, 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 : 64-67

publication ID

https://doi.org/ 10.5281/zenodo.4619317

persistent identifier

https://treatment.plazi.org/id/4C3B87DF-7C2C-FFC2-FC1B-F9EA538AFB4A

treatment provided by

Carolina

scientific name

Leucosia major
status

sp. nov.

Leucosia major View in CoL , new species

( Figs. 1 View Fig C-F, 4)

Material examined. – Holotype - male (38.0 by 34.0mm) ( ZRC 1984.50 View Materials ), South China Sea, off Singapore, coll. H. Huat, 26 Nov.1982.

Paratypes – 1 male (37.1 by 32.0 mm) ( ZRC 1984.6325 View Materials ), 1 ovigerous female (38.5 by 39.0 mm) ( ZRC 1984.6326 View Materials ), South China Sea, off Singapore, about 30 miles from Horsburgh Lighthouse, coll. H. Huat , 1980s; 1 female (36.0 by 31.9 mm) ( ZRC 1985.79 View Materials ), South China Sea, station B77, 6-7 fathoms, mud, coll. Singapore Fisheries Research Center, 1955-1956 .

Diagnosis. – Carapace somewhat rhomboidal, 1.12-1.16 times as long as broad. Median part, from front to intestinal

region more convex than lateral sides. Hepatic region slightly elevated, other regions indistinct. Front divided into 3 teeth: median tooth produced anteriorly downwards, broad, long, lateral teeth bluntly narrow, short, distal ends of all 3 teeth bluntly rounded. Anterolateral margin and distal half of posterolateral margin with fine granules. Posterior carapace margin with distinct granules. Thoracic sinus shallow, with setae, base of sinus with 7 granular tubercles, of which first and seventh tubercles smaller than others, with 2-3 fine granules behind seventh tubercle. Exopod of third maxilliped slender, long, 4.5 times as long as broad, distal end reaching distal part of merus of endopod; merus narrowly triangular, 2.5 times as long as broad, longer than ischium; distal part of female ischium elevated, inner side and base of merus with longitudinal row of setae; male ischium not elevated, glabrous. Chelipeds stout, merus twice as long as broad, distal end broader than basal half, median part of distal one-third elevated, dorsum of distal two-thirds smooth, without granules, dorsal surface of basal half near outer border with patch of 10 fine granules, anterior part with 2 longitudinal rows of 2 or 3 similarly shaped granules; carpus subglobate; palm flattened, 1.5 times as long as broad, borders thin, inner border with coarse granules; movable finger shorter than palm, cutting edges of both fingers with indistinct teeth. First pair of ambulatory legs longest, other legs gradually shorter, last pair shortest. Male abdomen with 5 free segments; segments 3-5 fused, stout, short, borders sinuous; segment 1 short, broad; segment 2 very small; segment 6 broad, flattened, distal part of borders narrowed; telson equilaterally triangular. Female abdomen longitudinally ovate, segments 3-6 fused, stout, large, suture between fused third and fourth segments visible; segment 1 very short, visible only laterally; median part pf segment 2 protruding posteriorly; telson triangular, 1.18 times as long as broad, borders with short setae. G1 stout, sinuous, distal part corneous, hard, yellow (in preservative), surrounded by long setae, finger-like process slightly curving inwards.

Color (in alcohol). – Anterior two-thirds of carapace grayish brown, posterior one-third pale brown, each side of meso- gastric region with 4 white spots in 2 oblique rows followed by longitudinal rows of white stripes. Each side of cardiac region with indistinct black blotch.

Etymology. – The name is derived from the Latin for large, alluding to the relatively large size of the species.

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

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Leucosiidae

Genus

Leucosia

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