Terrathelphusa mas, Grinang, Jongkar & Ng, Peter K. L., 2015

Grinang, Jongkar & Ng, Peter K. L., 2015, The identity of the semiterrestrial crab Terrathelphusa kuchingensis (Nobili, 1901) (Crustacea: Decapoda: Brachyura: Gecarcinucidae), with descriptions of four new species from southwestern Sarawak, Borneo, Malaysia, Zootaxa 3946 (3), pp. 331-346 : 341-344

Terrathelphusa mas n. sp.

( Figs. 9 A–H, 10A–E, 11I, J) Material examined. Holotype: male (35.5 × 26.4 mm) ( ZRC 2015.0005), open green golf course, Borneo Highlands Resort, Gunung Penrissen, Kuching, Sarawak, 1O07’43.8”N 110O13’07.3”E, 852 m asl, coll. J. Grinang et al., 16 September 2013. Paratype: 2 females (larger 26.3 × 20.4 mm) (SBC.C.00374–75); 1 female ( ZRC 2014.0840); data same as holotype.

Diagnosis. Carapace broader than long, conspicuously swollen, surface convex, smooth; cervical grooves broad, deep; epigastric cristae high, separated by deep epigastric groove; H-groove deep, long almost confluent with cervical grooves; epibranchial tooth indistinct but can be separated from external orbital angle by notch, anterolateral, frontal regions appearing compressed, supraorbital margin almost parallel with frontal margin; epistome median lobe blunt to bifurcated ( Fig. 9 A–C). Male abdomen with elongated somite 6, lateral margins gently concave ( Fig. 9 D). Third maxilliped ischium rectangular, about 2.1 times maximum width ( Fig. 9 E). Ambulatory legs smooth, relatively slender, length about 4.4 times width ( Fig. 9 F). Cheliped carpus rugose, without granules ( Fig. 9 G, H), inner angle with narrower, acutely triangular tooth; gap between fingers of major chela conspicuously wide ( Fig. 9 A). G1 distinctly curving outwards; terminal segment cone-shaped, tapered, gently curving upwards to tip, about 0.3 times length of subterminal segment ( Fig. 10 A, B, D, E). Distal segment of G2 relatively long, about 0.8 times length of basal segment ( Fig. 10 C).

Life colour. Body and appendages are bright golden yellow ( Fig. 11 I, J).

Variation. The paratypes agree well with the holotype male except for variations in a few characters. In the larger specimens, the ambulatory legs are relatively longer and the cervical grooves are somewhat broader than in smaller specimens.

Habitat. The species is sympatric with T. aglaia n. sp., at high elevations on Gunung Penrissen, but it absent at low elevations.

Etymology. Derived from the Iban word mas for gold alluding to the golden appearance of the new species. The name is used as a noun in apposition.

Characters T. aglaia T. cerina T. kuchingensis T. kundong T. loxophthalma * T. mas T. ovis * T. telur* Third Length of ischium Length of ischium Length of ischium Length of Length of ischium Length of ischium Length of ischium Length of maxilliped about 1.9 times about 2.0 times about 1.8 times ischium about about 1.8 times about 2.1 times about 1.6 times ischium about

maximum width maximum width maximum width 1.9 times maximum width maximum width maximum width 1.5 times

maximum width maximum width Remarks. Terrathelphusa mas n. sp., can be distinguished from T. kuchingensis and the other species being described by a combination of characters: inner angle of carpus having a narrow and acutely triangular tooth ( Fig. 9 A) (versus broad and acutely triangular tooth in T. kuchingensis ( Fig. 1 A), T. aglaia n. sp. ( Fig. 3 A) and T. cerina n. sp. ( Fig. 5 A), and broadly triangular tooth in T. kundong n. sp. ( Fig. 7 A); and the G1 is distinctly curving outwards ( Fig. 10 A, B, C, D) (versus gently curving outwards in others, Figs. 2 A, B, D, E; 4A, B, D, E; 6A, B, D, E; 8A, B, D, E). Terrathelphusa species from the Kuching region differ from taxa in the northern region viz. T. loxophthalma , T. ovis and T. telur as summarised in Table 1 .

Figures

FIGURE 1. Terrathelphusa kuchingensis (Nobili, 1901), male (36.0 × 26.4 mm) (ZRC 2015.0001), Gunung Temurang, Kuching, Sarawak, Padawan-Penrissen limestone formation. A, overall dorsal view; B, dorsal view of carapace; C, frontal view of carapace; D, ventral view showing anterior thoracic sternum and male abdomen; E, left third maxilliped; F, outer view of right fourth ambulatory leg; G, outer view of right chela; H, outer view of left chela.

FIGURE 2. Terrathelphusa kuchingensis (Nobili, 1901), male (36.0 × 26.4 mm) (ZRC 2015.0001), Gunung Temurang, Kuching, Sarawak, Padawan-Penrissen limestone formation. A, ventral view of left G 1; B, ventral view of distal part of left G 1; C, dorsal view of left G 2; D, dorsal view of G 1; E, dorsal view of distal part of left G 1. Scales: A, C, D = 1 mm; B, E = 0.5 mm.

FIGURE 3. Terrathelphusa aglaia n. sp., holotype male (35.9 × 26.6 mm) (ZRC 2015.0002), sandstone outcrop, Gunung Penrissen, Kuching, Sarawak. A, overall dorsal view; B, dorsal view of carapace; C, frontal view of carapace; D, ventral view showing anterior thoracic sternum and male abdomen; E, left third maxilliped; F, outer view of right fourth ambulatory leg; G, outer view of right chela; H, outer view of left chela.

FIGURE 5. Terrathelphusa cerina n. sp., holotype male (24.7 × 19.3 mm) (ZRC 2015.0003), sandstone outcrop, Gunung Singai, Bau, Kuching, Sarawak. A, overall dorsal view; B, dorsal view of carapace; C, frontal view of carapace; D, ventral view showing anterior thoracic sternum and male abdomen; E, left third maxilliped; F, outer view of right fourth ambulatory leg; G, outer view of right chela; H, outer view of left chela.

FIGURE 7. Terrathelphusa kundong n. sp., holotype male (29.4 × 21.9 mm) (ZRC 2015.0004), sandstone outcrop, Gunung Serambu, Bau, Kuching, Sarawak. A, overall dorsal view; B, dorsal view of carapace; C, frontal view of carapace; D, ventral view showing anterior thoracic sternum and male abdomen; E, left third maxilliped; F, outer view of right fourth ambulatory leg; G, outer view of right chela; H, outer view of left chela.

FIGURE 9. Terrathelphusa mas n. sp., holotype male (35.5 × 26.4 mm) (ZRC 2015.0005), sandstone outcrop, Gunung Penrissen, Kuching, Sarawak. A, overall dorsal view; B, dorsal view of carapace; C, frontal view of carapace; D, ventral view showing anterior thoracic sternum and male abdomen; E, left third maxilliped; F, outer view of right fourth ambulatory leg; G, outer view of right chela; H, outer view of left chela.

FIGURE 10. Terrathelphusa mas n. sp., holotype male (35.5 × 26.4 mm) (ZRC 2015.0005), sandstone outcrop, Gunung Penrissen, Kuching, Sarawak. A, ventral view of left G 1; B, ventral view of distal part of left G 1; C, dorsal view of left G 2; D, dorsal view of G 1; E, dorsal view of distal part of left G 1. Scales: A, C, D = 1 mm; B, E = 0.5 mm.

FIGURE 11. Life colour of five species of Terrathelphusa from Kuching Division, Sarawak. A, B, Terrathelphusa kuchingensis (Nobili, 1901), male (36.0 × 26.4 mm) (ZRC 2015.0001), shortly after collection, Gunung Temurang; C, D, Terrathelphusa aglaia n. sp., holotype male (35.9 × 26.6 mm) (ZRC 2015.0002), Gunung Penrissen; E, F, Terrathelphusa cerina n. sp., female (24.2 × 20.1 mm), captured-marked-released, Gunung Singai; G, H, Terrathelphusa kundong n. sp., female (30.8 × 23.0 mm) (SBC. C. 00364 - 65), Gunung Serambu; I, J, Terrathelphusa mas n. sp., holotype male (35.5 × 26.4 mm) (ZRC 2015.0005), Gunung Penrissen.