ON THE NEW RECORD OF Lithoselatium kusu Schubart , Liu and Ng , 2009 FROM INDONESIA ( CRUSTACEA : BRACHYURA : SESARMIDAE

Lithoselatium kusu Schubart, Liu and Ng, 2009 previously known from Singapore and surrounding areas, is reported in this paper for the first time from Indonesia. The specimens for this study were collected from under rocks and coral rubble around mangrove areas in Lingga, Indonesia. The morphological characteristics and differences of the three known species of the genus of Lithoselatium are presented.

The sesarmid genus Lithoselatium was established by Schubart et al. (2009) describing two species: Lithoselatium pulchrum from Taiwan and L. kusu from Singapore and surrounding areas.
Following the genus establishment, Promdan and Ng (2009) described the third species, L. tantichodoki, from the Gulf of Thailand.
Recently several specimens of Lithoselatium kusu were collected during the Health Monitoring of coral reef project in the North Lingga and adjacent areas in Lingga District, Riau Archipelago, eastern Sumatra, Indonesia.This species is herein reported for the first time in Indonesian waters and represents the second record after its description.
The genus Lithoselathium is easily recognized by its slightly trapezoidal shape of the carapace which is diverging towards the posterior margin, the dactylus of the ambulatory legs distinctly longer than half of the propodi, the presence of prominent tufts of setae between coxae of the ambulatory legs 2 and 3, and part of the sternite 8 being exposed when the male abdomen is fully closed (Schubart et al., 2009).

MATERIAL AND METHODS
The first author collected specimens from under rocks and coral rubble around mangrove area of Pulau Bakau Kecil, Pulau Buluh, Pulau Kongka and Pulau Kentar in Lingga, Riau Archipelago, Indonesia (Figure 1).We deposited the specimens in the Reference Collection of Research Center of Oceanography (RCO) -Indonesian Institute of Sciences (LIPI), Jakarta, Indonesia.The holotype of L. kusu Schubart, Liu & Ng, 2009, L. pulchrum Schubart, Liu & Ng, 2009, and L. tantichodoki Promdan & Ng, 2009, housed in the Lee Kong Chian Natural History Museum (ZRC), National University of Singapore, was examined by the second author.The carapace breadth at the widest point followed by the length was measured in millimeters (mm).The abbreviation G1 is used for the male first gonopod.

REMARKS
The specimens in this study agree with the description of the holotype of L. kusu from Singapore.Variation was noted on the number of pectinated crest on the palm, and dactylar tubercles of the chelipeds, which have 35 or 36 teeth versus 33−35 tubercles respectively.In the holotype, the pectinated crest on the palm of chelipeds consists of 33 or 34 teeth, and the dorsal surface of the dactylus of the chelipeds has a row of 30−32 tubercles.Morphological differences and geographical distribution of L. pulchrum, L. kusu, and L. tantichodoki are presented in Table 1.The carapace width of the female specimens in this study is between 5.8-13.2mm,and the abdomen is not fully developed (Figure 5), therefore it is not reaching the coxae of the ambulatory legs.It is possibly because they are still not sexually mature.The adult female paratype has a carapace width of 21.2mm (cf.Schubart et al., 2009, Figure 13B, 13C).

HABITAT
As mentioned by Schubart et al., (2009), species of Lithoselatium inhabit the supralittoral zone, under rock and boulders.However, unlike L. kusu from Singapore that was recorded in coarse rock and coral rubbles well above the water line (Schubart et al., 2009), the L. kusu studied here were collected in mangrove environments, under rock and dead coral rubbles in the littoral zone in Riau archipelago.