(Figs. 35–37, 40K)

Material examined. Holotype: male (15.2 × 11.3 mm) (MZB Cru 4804), Minajerwi Estuary, Timika, Papua Indonesia, coll. 28 June 2004. Paratypes: 1 female (7.3 × 5.7 mm) (MZB Cru 4805), Arafura Sea, coll. 17 April 2000; 1 male (8.5 × 6.8 mm), 1 female (8.5 × 6.5 mm) (ZRC 2018.0275), station 7C, Arafura Sea, 4°46’18.95’’S 136°28’02.64’’E, Papua, Indonesia, coll. 19 April 2000.

Diagnosis. Carapace (Figs. 35A, 36A, B) about 1.4 times broader than long, surface smooth, long setae on lateral margin, regions indistinct, H-shaped gastro-cardiac grooves distinct; anterolateral margin arcuate, lined with small granules, separated into 3 broad lobes; posterolateral surface and margin with scattered tubercles. Front (Figs. 35A, B, 36A, B) bilobed, with shallow median cleft, margin of each lobe convex. Orbit (Fig. 35B) short, bulbous ocular peduncles filling orbit, immovable, cornea small, slightly pigmented. Epistome (Fig. 35B) relatively broad, posterior margin concave.Antennal peduncles relatively long. Third maxilliped (Fig. 37A) with merus broad, squarish, outer and inner margins straight, ischium slightly broader, much longer than merus, inner margin slightly shorter than outer margin, lower margin slightly oblique; exopod relatively stout. Chelipeds unequal in males, subequal in females (Figs. 35A, F, G, 36 C–E), outer surface of finger of major chela smooth, with shallow longitudinal groove and scattered tubercles proximally, longitudinal groove on fixed finger, surface of palm smooth medially, upper and lower outer margin with scattered setae; cutting edges of fingers with prominent teeth; surface of carpus smooth, margin with short setae, inner angle with long, sharp teeth in larger specimens; dorsolateral margin of merus with row of large tubercles, margins covered with long setae; inner angle of carpus with low to sharp tooth (Figs. 35E, 36 C–E). P2−P5 (Fig. 35A) proportionally long, fringe by long setae on dorsal and ventral margins; merus of P5 not reaching front when folded. Fused thoracic sternites 1, 2 broadly triangular (Figs. 35C, 36G), proportionally narrow; thoracic sternites 3, 4 partially fused, with only lateral suture discernible. Male pleon (Figs. 35C, D, 37B) relatively broad, telson long, 1.7 times as long as somite 6, triangular. G1 (Figs. 37 C–F, 40K) slender, curved, upper half much longer than lower half, distal part relatively short, gently curved, with pointed tip. Anterolateral margin of female carapace with relatively lower teeth; pleon (Fig. 36F) broad, somite 1 reaching coxae of fourth ambulatory legs, tapering to pointed edge; telson subtriangular; vulva (Fig. 36G) large, ovate.

Etymology. From the Latin “robustus” for strong, alluding to the thick carapace.

Remarks. The shape of the third maxilliped and the G1 structure of T. robustus n. sp. resemble those of T. tonsuratus from Moreton Bay in Queensland, Australia. Typhlocarcinops robustus n. sp., however, has a broader carapace (1.4 times as broad as long) which is also thick and strongly vaulted, without any trace of tomentum of the carapace (Figs. 35A, 36A, B) (versus carapace 1.2 broader than long, covered with tomentum, and vaulted only posterolaterally in T. tonsuratus; cf. Griffin & Campbell 1969: fig. 3A; present Fig. 34A), and the male pleon is proportionately much broader with the telson triangular and about 1.7 times the length of somite 6 (Figs. 35C, D, 37B) (versus the male pleon is more narrow with the telson subtriangular, and 1.8 times the length of somite 6 in T. tonsuratus; cf. Griffin & Campbell 1969: fig. 3C; present Fig. 34D). Their G1 structures are different with that of T. tonsuratus having the distal third gently curved upwards and the tip is upcurved (Griffin & Campbell 1969: fig. 6B; present Fig. 34 E–G) (versus it is strongly sinuous with the distal part curved outwards like a hook for T. robustus Fig. 37 C–F).

Typhlocarcinops robustus n. sp. differs from T. canaliculatus in possessing a relatively stockier carapace which is higher (Figs. 35A, B, 36A, B) (versus carapace relatively less raised in T. canaliculatus; cf. Figs. 8B, C, 9 A–C, 10A, 11A, B); the anterior male thoracic sternum (notably sternites 3 and 4) are proportionately wider (Fig. 35C) (versus anterior male thoracic sternites proportionately more narrower transversely in T. canaliculatus; cf. Figs. 8D, 9E, 10B, 11D); the male pleonal somite 6 is proportionately wider with the telson distinctly triangular in shape (Fig. 37B) (versus male pleonal somite 6 more quadrate and the telson more rounded in T. canaliculatus; cf. Figs. 13C, H, 14G, 15C, D); and the G1 distal part is relatively less distinctly curved (Fig. 37 C–F) (versus G1 distal part relatively more curved in T. canaliculatus; cf. Figs. 13 D–G, I–L, 14B–E, H–K, 15E‒G).

The inner angle of the carpus of the chelipeds and the anterolateral margin of the carapace varies in relation with the size and sex. In contrast to the holotype male, the inner angle of the cheliped in the small male and female specimens is not armed with a strong tooth but only with a broad protuberance, and the anterolateral margin of the carapace has low teeth or lobes (Fig. 36 C–E). These specimens are assigned to T. robustus by the same characters: the male telson is long, triangular, the same shape as in the large male holotype, the carapace is thick, fringed with long setae on the lateral margins and the chelipeds are granular on the upper and lower outer surface.

Type locality. Timika, Papua Indonesia.

Distribution. Arafura Sea, Papua. On soft sediments, 10– 40 m.