Lepidothelphusa sangon, Grinang & Ng, 2015

Grinang, Jongkar & Ng, Peter K. L., 2015, Taxonomy of the semiterrestrial crab Lepidothelphusa cognettii (Nobili, 1903) (Crustacea: Decapoda: Brachyura: Gecarcinucidae), with descriptions of five new species from Sarawak, Malaysia, Borneo, Raffles Bulletin of Zoology 63, pp. 564-582 : 576-578

Lepidothelphusa sangon , new species

( Figs. 11A–I , 12A–E , 14E, F )

Material examined. Holotype: male (8.4 × 7.6 mm) ( ZRC 2015.0611 ), Nawang Waterfall , 187 m above sea level, Bung Bratak , Bau, Sarawak, coll. PKL Ng et al., 14 September 2013 . Paratypes: 14 males (largest 8.0 × 7.1 mm), 7 females, 2 ovigerous females (largest 7.4 × 6.0 mm), 1 juvenile ( ZRC 2015.0612 ), data same as holotype ; 4 males (largest 9.0 × 7.9 mm) (SBC.00431–34), location same as holotype, coll. J Grinang et al., 14 September 2013 ; 1 male (8.0 × 7.0 mm) (SBC.C.00476), location same as holotype, J Grinang, 1 May 2013 .

Diagnosis. Carapace quadrate, surface relatively flat, rugose, anterolateral margins smooth; antero- and posterolateral regions rugose; epibranchial tooth undiscernible; external orbital tooth with outer margin concave, smooth; serrated projection on frontal region distinct; epigastric and postorbital cristae distinct, margins serrated; cervical and H-grooves shallow, not confluent ( Fig. 11A, B, D ); ischium of third maxilliped rhomboidal, slightly longer than broad sulcus undiscernible ( Fig. 11F ); inner margin of merus of chelipeds with relatively lower serrated projection ( Fig. 11G ); carpus of chelipeds rugose, inner angle with broad, low triangular tooth ( Fig. 11A ); fingers of adult major male chela gaping ( Fig. 11H, I ); ambulatory legs short, merus of fourth ambulatory legs about half of length of carapace ( Fig. 11A, E ); male abdomen triangular, somite 6 width and length subequal, subequal to length of telson ( Fig. 11C ); G1 stout, slightly sinuous, basal segment weakly constricted on distal third; terminal segment slightly curving outwards in dorsal view, almost straight in ventral view ( Fig. 12A, B, D, E ); G2 with relatively long distal segment, about half length of basal segment ( Fig. 12C ).

Colour. In life, both sexes are red to reddish-brown with yellow chelipeds ( Fig. 14E, F ). The colour in females is slightly less striking.

Etymology. The name is derived from the Bidayuh word “sangon” for beautiful, alluding to the striking colour of the crab. The name is used as a noun in apposition.

Remarks. Lepidothelphusa sangon , new species, can be easily distinguished from L. cognettii s. str., L. limau , new species, and L. padawan , new species, by its relatively small adult size (males and females are already fully mature at 8.0 mm carapace width). Its size range is similar to L. flavochela , new species, and L. loi , new species, but distinguishable from the latter by its striking reddish carapace and ambulatory legs ( Fig. 14E, F versus Figs. 13C, D , 14A, B ). It is close to L. limau , but can be distinguished by its more squarish and flat carapace ( Fig. 11B versus Fig. 5B ), relatively smaller projection on the merus of the cheliped ( Fig. 11G versus Fig. 5G ), narrower gap of the fingers of chela ( Fig. 11H versus Fig. 5H ) and relatively shorter G1 ( Fig. 12A, D versus Fig. 6A, D ).

Habitat. The habitat is moist rocks and leaf litter, in partially exposed or shaded, small streams in old primary dipterocarp forests. The substrate is mudstone and the site is less than 200 m above sea level.

Figures

Fig. 11. Lepidothelphusa sangon, new species, holotype male (8.4 × 7.6 mm) (ZRC 2015.0611), Nawang Waterfall, Bung Bratak, Bau, Sarawak. A, overall dorsal view of habitus; B, dorsal view of carapace; C, ventral view showing anterior thoracic sternum and male abdomen; D, frontal view of carapace; E, outer view of right fourth ambulatory leg; F, left third maxilliped showing exopod; G, left cheliped showing serrated inner margin of merus; H, outer view of left chela; I, outer view of right chela.

Fig. 12. Lepidothelphusa sangon, new species, holotype male (8.4 × 7.6 mm) (ZRC 2015.0611), Nawang Waterfall, Bung Bratak, Bau, Sarawak. A, dorsal view of left G1; B, dorsal view of distal part of left G1; C, dorsal view of left G2; D, ventral view of left G1; E, ventral view of distal part of left G1. Scale bars = 0.5 mm.

Fig. 14. Live colours of three Lepidothelphusa species from Kuching Division, southwestern Sarawak. A, B, Lepidothelphusa loi, holotype male (10.3 × 9.6 mm) (ZRC 2015.0607), Gunung Ampungan, Sadong River Basin, Serian, Sarawak; C, D, Lepidothelphusa padawan, new species, paratype male (15.8 × 13.2 mm) (SBC.C.00440–4), Bung Brungu, Padawan, Sarawak; E, F, Lepidothelphusa sangon, new species, paratype male (8.0 × 7.0 mm) (SBC.C.00476), Nawang Waterfall, Bung Bratak, Bau, Sarawak.

Fig. 13. Live colours of three Lepidothelphusa species from Kuching Division, southwestern Sarawak. A, B, Lepidothelphusa cognettii (Nobili, 1903), male (12.0 × 10.2 mm) (SBC.C.00382–90), Batu Panggah Trail, Gunung Penrissen, Sarawak; C, D, Lepidothelphusa flavochela, new species, paratype male (8.5 × 7.5 mm) (SBC.C.00392–401), Pagar Besi, Kampung Gumbang, Bau, Sarawak; E, F, Lepidothelphusa limau, new species, paratype male (10.5 × 9.7 mm) (SBC.C.00402–05), Kampung Peros, Bau, Sarawak.

Fig. 5. Lepidothelphusa limau, new species, holotype male (12.1 × 10.8 mm) (ZRC 2015.0605), Kampung Peros, Krokong, Bau, Sarawak. A, overall dorsal view of habitus; B, dorsal view of carapace; C, ventral view showing anterior thoracic sternum and male abdomen; D, frontal view of carapace; E, outer view of right fourth ambulatory leg; F, left third maxilliped showing exopod; G, left cheliped showing serrated inner margin of merus; H, outer view of left chela; I, outer view of right chela.

Fig. 6. Lepidothelphusa limau, new species, holotype male (12.1 × 10.8 mm) (ZRC 2015.0605), Kampung Peros, Krokong, Bau, Sarawak. A, dorsal view of left G1; B, dorsal view of distal part of left G1; C, dorsal view of right G2; D, ventral view of left G1; E, ventral view of distal part of left G1. Scale bars = 0.5 mm.