Typhlocarcinops hamus, Ng & Rahayu, 2020

Ng, Peter K. L. & Rahayu, Dwi Listyo, 2020, A synopsis of Typhlocarcinops Rathbun, 1909 (Crustacea: Decapoda: Brachyura: Pilumnidae), with descriptions of nine new species from the Indo-West Pacific, Zootaxa 4788 (1), pp. 1-100 : 46-48

publication ID

https://doi.org/ 10.11646/zootaxa.4788.1.1

publication LSID

lsid:zoobank.org:pub:7A461DBA-00B7-48DB-9320-4775DA8F21B2

persistent identifier

https://treatment.plazi.org/id/03C05222-FF8F-FC23-FF35-D207FB63F990

treatment provided by

Plazi

scientific name

Typhlocarcinops hamus
status

sp. nov.

Typhlocarcinops hamus View in CoL n. sp.

( Figs. 38 View FIGURE 38 , 39 View FIGURE 39 , 40L View FIGURE 40 )

Material examined. Holotype: male (5.0 × 3.5 mm) (MNHN-IU-2013-1441a), station PD73, Yomba Island , 0514.7’S 14547.3’E, 20–25 m, Papua New Guinea, coll. Expedition Papua Niugini, 6 December 2012 . Paratypes: 1 male (3.6 × 2.6 mm) (MNHN-IU-2013-1441b), 2 males (4.6 × 3.2 mm, 4.1 × 3.0 mm) ( ZRC 2018.0735 View Materials ), same data as holotype. Others : 1 poorly preserved male (4.1 × 2.8 mm) (with Sacculina ) ( ZRC 2019.1704 View Materials ), stn PD73, Yomba Island, 05°14.7’S 145°47.3’E, 20-25 m, Papua New Guinea, coll. A. Anker, Expédition PAPUA NIUGINI, 6 December 2012 GoogleMaps .

Diagnosis. Carapace about ( Fig. 38A, B View FIGURE 38 ) 1.4 times broader than long, surface glabrous medially, slightly narrowing on posterolateral margin, regions demarcated, H-shaped gastro-cardiac grooves shallow, indistinct, anterolateral margin arcuate, lined with small granules, separated by 2 shallow depressions, forming 3 broad lobes; posterolateral margin subparallel antero and posterolateral surface with scattered tubercles. Front bilobed ( Fig. 38B, C View FIGURE 38 ), with shallow median cleft, margin of each lobe convex. Orbit ( Fig. 38B, C View FIGURE 38 ) short, bulbous ocular peduncles filling orbit, immovable, cornea small, pigmented. Epistome ( Fig. 38C View FIGURE 38 ) relatively broad, triangular median lobe with slight median suture. Antennal peduncles long. Third maxilliped ( Fig. 39A View FIGURE 39 ) with outer margin of merus broad, outer and inner margins straight, anteroexternal angle rounded; ischium slightly broader, but much longer than merus, inner margin slightly shorter than outer margin; exopod relatively slender. Chelipeds unequal in males ( Fig. 38A, G, H View FIGURE 38 ), fingers of major chela smooth, outer surface of dactylus and fixed finger with longitudinal ridge, long fine setae on upper and lower margins of dactylus and fixed finger, cutting edges with prominent broad teeth; palm with sparse granules on upper and lower outer surface, smooth medially, carpus and merus smooth, tufts of sparse setae on its surfaces; carpus without protuberance ( Fig. 38E, F View FIGURE 38 ). P2−P5 proportionally long ( Fig. 38A View FIGURE 38 ), dorsal and ventral mar- gins fringe with sparse, long setae; dactylus straight; merus of P5 not reaching front when folded. Fused thoracic sternites 1, 2 broadly triangular ( Fig. 38D View FIGURE 38 ), proportionally narrow; thoracic sternites 3, 4 fused, suture discernible. Male pleon ( Figs. 38D View FIGURE 38 , 39B View FIGURE 39 ) relatively broad; telson relatively long, 1.7 times as long as somite 6, with rounded distal margin. G1 ( Figs. 39 View FIGURE 39 C–F, 40L) slender, slightly curved, upper half longer than lower half, distal part strongly curved, directed inwards, ending in pointed tip, with setae subdistally.

Etymology. The name is derived from the Latin for hook, alluding to the G1 structure. The name is used as a noun.

Remarks. The curved G1 distal part in T. hamus n. sp. is a character shared with T. raouli n. sp., which differs in the degree of curvature. In T. raouli n. sp., the curved distal part form is hook-shaped with a flared and rounded tip that is directed obliquely laterally ( Fig. 44 View FIGURE 44 C–F) versus strongly curved with the pointed tip directed inwards in T. hamus n. sp. ( Figs. 39 View FIGURE 39 C–F, 40L).

Type locality. Yomba Island , Papua New Guinea .

Distribution. Only known from Yomba Island, Papua New Guinea. From depths of 20− 25 m.

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