Terrathelphusa aglaia, 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: 334-335

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Terrathelphusa aglaia

n. sp.

Terrathelphusa aglaia  n. sp.

( Figs. 3View FIGURE 3 A –H, 4 A –E, 11 C, D)

Material examined. Holotype: male (35.9 × 26.6 mm) ( ZRC 2015.0002), open green golf course, Borneo Highlands Resort, Gunung Penrissen, Kuching, Sarawak, 1 O07’ 43.8 ”N 110 O 13 ’07.3”E, 852 m asl, coll. J. Grinang et al., 16 September 2013. Paratype: 1 male (32.3 × 23.8 mm), 1 female (37.3 × 27.5 mm) (SBC.C.00361– 62), data same as holotype; 1 juvenile (17.9 × 14.2 mm) (SBC.C.00363), steep soil bank of Sungai Biduan, based of Gunung Penrissen, Sarawak, 1 O08’ 48.6 ”N 110 O 14 ’ 23.9 ”E, 172 m asl, coll. J. Grinang et al., 8 July 2013; 1 male (27.5 × 21.1 mm), 3 females (largest 35.5 × 26.2 mm) ( ZRC 2014.0844), coll. J. Grinang et al., 15 September 2013, locality 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 pointed ( Fig. 3View FIGURE 3 A –C). Male abdomen with elongated somite 6, lateral margins gently concave ( Fig. 3View FIGURE 3 D). Ischium of third maxilliped rectangular, about 1.9 times maximum width ( Fig. 3View FIGURE 3 E). Ambulatory legs smooth, relatively slender, second pair longest; length of fourth merus about 3.9 times width ( Fig. 3View FIGURE 3 F). Cheliped carpus rugose, without granules ( Fig. 3View FIGURE 3 G, H), inner angle with acutely triangular tooth; gap between fingers of major chela wide ( Fig. 3View FIGURE 3 A). G 1 gently curving outwards; terminal segment cone-shaped, tapered, slightly curving upwards, about 0.3 times length of subterminal segment ( Fig. 4View FIGURE 4 A, B, D, E). Distal segment of G 2 relatively long, about 0.8 times length of basal segment ( Fig. 4View FIGURE 4 C).

Life colour. The carapace is dark crimson, chelipeds and legs reddish to purplish ( Fig. 11View FIGURE 11 C, D). The juvenile is purple-reddish overall.

Variation. The additional specimens agree very well with the holotype male, differing only in minor nonsexual characters: the epistome median lobe varies from blunt to pointed, which is not associated with size or sex; and in larger specimens, the cervical grooves are proportionately broader, with the ambulatory legs relatively slightly longer.

Habitat. Bases of sandstone outcrops from low to high elevations. Their burrows in moist compact soil are about 1 m deep.

Etymology. The name is derived from the Latin aglaia  for beauty or splendor alluding to the striking purplish carapace and reddish legs of the species. The name is used as a noun in apposition.

Remarks. Terrathelphusa aglaia  n. sp., is easily distinguishable from its Sarawak congeners by its striking colour: dark crimson carapace, reddish to purplish chelipeds and legs ( Fig. 11View FIGURE 11 C –D). Other than in coloration, T. aglaia  n. sp. is relatively close to T. kuchingensis  but has a distinctly less swollen and convex carapace than the latter ( Fig. 1View FIGURE 1 A vs. Fig. 3View FIGURE 3 A). The G 1 subterminal segment of T. aglaia  n. sp. is also relatively more slender, with the terminal segment straight ( Fig. 4View FIGURE 4 A, B, D, E) (subterminal segment relatively broader with the terminal segment curving in T. kuchingensis  , Fig. 2View FIGURE 2 A, B, D, E). Differences between T. aglaia  n. sp., and congeners are summarised in Table 1.


Zoological Reference Collection, National University of Singapore