Some lithodid crabs ( Crustacea : Decapoda : Lithodidae ) from the Solomon Islands ( SW Pacific Ocean ) , with the description of a new species *

During a recent expedition to the Solomon Islands (September-October 2001, cruise SOLOMON 1), an interesting collection of lithodid crabs was obtained. The lithodid fauna in this area of the Western Pacific Ocean is not well known, although some species have been reported in adjacent waters (Dawson, 1989; Macpherson, 1990, 2001; de Saint-Laurent and Macpherson, 1997). The study of this material revealed the existence of four species belonging to the genera Neolithodes A. Milne Edwards and Bouvier, 1894 and Paralomis White, 1856. One of the species of Paralomis is new and is described herein. A key to the species of the genus from the western and central Pacific Ocean is also provided. SCI. MAR., 67 (4): 413-418 SCIENTIA MARINA 2003

The types of the new species, and other specimens are deposited in the collections of the Muséum National d'Histoire naturelle, Paris (MNHN).The measurements given are of carapace length x carapace width, excluding rostrum and lateral spines respectively.The terminology used follows Macpherson (1988Macpherson ( , 2001)), and de Saint Laurent and Macpherson (1997).

Distribution:
The species has previously been cited in Japan, between 200 and 950 m and Fiji Islands at 1058-1091 m.This new material was collected at 1036-1203 m.

Paralomis mendagnai n. sp.
(Figs 1-3) Description: Carapace more or less hexagonal, as long as wide.Dorsal carapace surface densely covered with rounded, more or less prominent granules of different size.Granules with minute setae.Regions well-defined, slightly convex.Gastric region somewhat more prominent than other regions, 3-4 large granules on epigastric region, slightly more prominent than others.Cardiac region roughly triangular, as prominent as branchial regions, separated from gastric region by deep transverse furrow.Cardiac region with 4 large granules, arranged in a square-shaped pattern.Branchial regions bearing some large granules each, 1 near gastro-cardiac furrow, 1 in middle of region, and 2 on posterior part, near intestinal region (Fig. 1).
Basal spine of rostrum more or less horizontal, slightly overreaching end of corneae, smooth on ventral side; 2 slightly divergent dorsal spines, upwardly directed, not reaching end of corneae.External orbital spine slightly shorter than eyes (Fig. 2B).Anterolateral spine shorter than external orbital, 1 small spine before cervical groove.Each branchial margin, including posterior margin, bearing 5-7 thick spines and some small spines (small specimens) or spiniform tubercles (large specimens).
Abdomen plates smooth, with numerous granules of various size (Fig. 2A).
Ocular peduncles with one small terminal spine, corneae well pigmented.
Basal segment of antennal peduncle with 1 distomesial spine.Scaphocerite with long, central spine, nearly reaching end of last segment of antennal peduncle, mesial and lateral margins unarmed, dorsal side with few small granules (Fig. 3).
Chelipeds subequal in length, right cheliped stouter than left.Merus armed with some spiniform tubercles and one strong distal spine on dorsal margin.Carpus bearing few spiniform tubercles, and 1 strong median spine on dorsal border.Palm bearing several rows of small tubercles and few spines on dorsal sides.Dactylus and propodal extension with tufts of hairs (Fig. 2C).
Walking legs moderately long.First and second walking legs slightly longer than third.Third walking leg in males more than 2 times carapace length, less than 2 times in females; with some acute gran- ules on terminal border of coxa; merus 0.75 carapace length in males and 0.5 in females, about 2 times longer than carpus and 1.3-1.5 times longer than propodus, with row of 5-8 small spines along dorsal border, few small spines on posterior and ventral sides.Carpus with 3 or 4 small spines along dorsal margin, dorsal side with 1 small distal spine.Propodus as long as dactylus, with 4-6 small spines along dorsal margin and 3 or 4 spinules along ventral margins.Dactylus slightly curved, unarmed in adult specimens and with small movable spinules along ventral margin in juveniles; with some scattered tuft of setae (Fig. 2D).
Remarks: Paralomis mendagnai belongs to the group of species with the dorsal surface of the carapace thickly covered with rounded, more or less prominent granules of different sizes.Among the species of the genus, P. medipacifica Takeda, 1974, from the Central Pacific, NW off Midway Islands (Takeda, 1974) is the most similar to the new species.This resemblance lies mainly in the overall carapace shape and armature; however, they differ as follows: -The chelipeds have more than one strong spine on the dorsal border of merus and carpus in P. medipacifica, whereas these articles are armed with only one strong spine in the new species.The walking legs have more spines and tubercles in P. medipacifica than in the new species; the dactylus has a row of well developed spinules along the ventral margin in adult specimens of P. medipacifica, whereas in the adult specimens of the new species this margin is unarmed.
-The scaphocerite is formed by a single, long central spine in P. mendagnai, whereas it is bifurcate in P. medipacifica.Distribution: Solomon Islands, 435-912 m.

KEY TO SPECIES OF PARALOMIS FROM THE WESTERN AND CENTRAL PACIFIC OCEAN
The genus Paralomis in the Western and Central Pacific Ocean comprises 22 species (see Dawson, 1989;Macpherson, 2001;Zaklan, 2002 and references cited therein).As previously mentioned, the distinctness of P. dofleini and P. haigae needs evaluation.Paralomis heterotuberculata from the East China Sea and described by Yumao et al. (1984) is considered a junior synonym of P. truncatispinosa from the same area and described by Takeda and Miyake (1980).The species described originally by Sakai (1980) as Lopholithodes odawari is here included in Paralomis.
The name mendagnai is given in honour of Alvaro de Mendaña, a Spanish explorer who discovered and named the Solomon Islands in 1568. Etymology: