Revision of Selatium Serène & Soh, 1970 (Crustacea: Brachyura: Sesarmidae), with description of a new genus and two new species Author Schubart, Christoph D. Author Liu, Hung-Chang Author Ng, Peter K. L. text Zootaxa 2009 2154 1 29 journal article 10.5281/zenodo.188831 370305cb-7612-43e1-853a-235c328dc888 1175-5326 188831 Lithoselatium kusu n. sp. ( Figs. 13–16 ) FIGURE 13. Lithoselatium kusu n. sp. , colour in life. A, dorsal view, paratype male (29.0 x 25.8 mm) (ZRC2009.0569), Singapore; B, dorsal view, paratype female (21.2 x 19.0 mm) (ZRC2009.0570), Singapore. A, B, dorsal views; C, ventral view. Material examined . Singapore : Holotype male (16.0 x 14.35 mm ) ( ZRC 2002.0149), Singapore : Kusu Island: between loose rocks, coll. C. D. Schubart, 26 December 1999 ( DNA voucher); paratypes : 1 male (16.8 x 14.95 mm ), 2 juvenile females (14.15 x 12.4 & 11.95 x 10.3 mm ) ( ZRC 2002.0150), same collection data as holotype ; 1 juvenile female ( ZRC 2009.0568), Sentosa Island: rock jetty, coll. C. D. Schubart, 15 August 1999 ; 7 males (largest 29.0 x 25.8 mm ), 9 females (largest 29.1 x 26.0 mm) ( ZRC 2009.0569), Raffles Lighthouse, coll. H. H. Tan et al ., 30 January 2002 ; 5 females (20.9 x 17.8, 19.2 x 16.2, 17.0 x 14.4, 17.0 x 14.5, 16.2 x 13.5 mm , smallest DNA voucher), 2 juvenile males (12.1 x 10.2, 11.31 x 9.64 mm ), 1 juvenile female (11.34 x 9.72 mm ) (SMF-33840), Labrador Beach, coll. C. D. Schubart, S. Klaus & P. Koller, 19 March 2006 ; 1 female (21.2 x 19.0 mm) ( ZRC 2009.0570), Raffles Lighthouse, Singapore , coll. P. K. L. Ng, 2 August 2008 . Other material: Malaysia , Sabah : 1 male molt (animal lost after molting in lab, photo voucher) (ca. 12.9 mm carapace width) ( ZRC 2000.1654), Pulau Manukan, coll. 22 June 2000 . FIGURE 14. Lithoselatium kusu n. sp. Holotype male (16.0 x 14.35 mm) (ZRC 2002.0149), Kusu Island, Singapore. A, dorsal view; B, dorsal view of carapace; C, frontal view of carapace. FIGURE 15. Lithoselatium kusu n. sp. Holotype male (16.0 x 14.35 mm) (ZRC 2002.0149), Kusu Island, Singapore. A, anterior thoracic sternum and abdomen; B, outer view of right chela; C, dorsal view of ridge on palm; D, ridge on dactylus of palm. FIGURE 16. Lithoselatium kusu n. sp. Holotype male (16.0 x 14.35 mm) (ZRC 2002.0149), Kusu Island, Singapore. A, abdomen; B, left third maxilliped (denuded); C, dorsal view of left G1 (denuded); D, ventral view of left G1 (denuded); E, dorsal view of distal part of left G1 (denuded); F, ventral view of distal part of left G1 (denuded). Type locality . Singapore , Kusu Island. Diagnosis . Carapace slightly trapezoidal, diverging toward posterior margin; lateral margins entire, without trace of epibranchial tooth ( Fig. 14 A, B); frontal margin with anterior lobes prominent, posterior lobes weakly demarcated ( Fig. 14 A, B); outer and inner surfaces of chelae smooth ( Fig. 15 B); dorsal margin of palm with one continuous longitudinal crest of proximal tubercles, followed by a pectinated crest consisting of 33 or 34 teeth, and approximately 5 or 6 partly fused distal tubercles (fewer, broader and shorter teeth in females); 3–5 short and oblique subsidiary rows of tubercles on inner side ( Fig. 15 C); dorsal margin of dactylar finger with a row of 30–32 tubercles, with circular rings and a central conical apex, more widely spaced towards distal part ( Fig. 15 D); cutting edge of with 2 larger teeth proximally and one larger tooth subdistally; cutting edge of pollex with 2 larger teeth proximally to medially and one larger tooth subdistally ( Fig. 15 B); G1 with pectinated distal part subtruncate, tip gently clefted, lower part larger than upper part ( Fig. 16 C–F). Proportionally shorter legs compared to L. pulchrum . FIGURE 17. Male thoracic sternum and abdomen. A, Selatium brockii (De Man, 1887) , male (29.2 x 26.9 mm) (ZRC 1989.2875), Mandai, Singapore; B, Lithoselatium pulchrum n. sp. , holotype male (23.5 x 20.8 mm) (ZRC 2002.0152), Kenting, Taiwan; C, Lithoselatium kusu n. sp. , holotype male (16.0 x 14.35 mm) (ZRC 2002.0149), Kusu Island, Singapore. a2–6 = abdominal somites 2–6; st5–8 = sternites 5–8; es5–7 = episternites 5–7; c2–5 = ambulatory coxa 2–5 Etymology . The name kusu is used as a noun and refers to the type locality of the new species, the small island south of Singapore . In Chinese kusu means “turtle”, describing the shape of the island. Colour . In life, carapace and legs purplish; carapace with yellowish-green mottling; chelae orangish-red ( Fig. 13 ). Remarks . Lithoselatium kusu n. sp. can be morphologically separated from L. pulchrum n. sp. by its proportionately shorter ambulatory legs and, if alive, by the strikingly different colour pattern. Ecology . Lithoselatium kusu is so far known from Labrador Beach, Kusu I., Sentosa I. and Raffles Lighthouse ( Singapore ) as well as from an island off Sabah. The species was found among coarse rock and coral rubble well above the water line in all localities. When chased, it moves rapidly between the rocks without necessarily seeking protection in the water.