Typhlocarcinops hirtus Ng & Rahayu 2020, n. sp.
Creators: name: Ng, Peter K. L.
name: Rahayu, Dwi Listyo
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Pilumnidae
Typhlocarcinops
Typhlocarcinops hirtus

description: Typhlocarcinops hirtus n. sp.   
(Figs. 62–64)  
 Material examined. Holotype: male (10.6 × 8.1 mm) (MZB Cru 4810), Kuta, coll. 18 August 2006. Paratypes: 1 female (11.4 × 8.3 mm) (MZB Cru 4811), 2 females (10.9 × 7.5 mm, 13.8 × 10.2 mm) (ZRC 2018.0273), same data as holotype; 1 male (11.8 × 8.1 mm) (MZB Cru 4812), Sekotong, coll. 16 May 2009; 1 male (15.0 × 11.0 mm) (ZRC 2015.0486), Sekotong, coll. 10 May 2007; 1 male (7.1 × 5.2 mm) (ZRC 2018.0274), Teluk Kombal, coll. D.L. Rahayu, April 2014; 1 male (11.7 × 8.4 mm) (ZRC 2015.0485) Jerowaru, coll. 10 May 2004; 1 female (8.6 × 6.1 mm) (ZRC 2013.1756), Medana, coll. 12 June 2007; 3 males (5.3 × 4.0 mm, 5.4 × 4.0 mm, 4.5 × 3.4 mm) (ZRC 2018.0718), Kuta, coll. D.L. Rahayu, 19 August 2008. All locations in Lombok Island, Indonesia.   
 Diagnosis. Carapace (Figs. 62A, B, 63B) 1.4−1.5 times broader than long, surface smooth, covered with short pubescence on surface, longer plumose setae on lateral and frontal margins, regions demarcated, H-shaped gastrocardiac grooves deep, distinct, anterolateral margin arcuate, lined with small granules, granules at junction with posterolateral margin separated by shallow indentation obscured by long setae; posterolateral margin subparallel, surface and margin with scattered tubercles. Front bilobed (Fig. 62B, C), with shallow median cleft, margin of each lobe convex. Orbit (Fig. 62C) short, bulbous ocular peduncles filling orbit, immovable, cornea small, pigmented. Epistome (Fig. 62C) relatively broad, triangular median lobe with median suture. Antennal peduncles long. Third maxilliped (Fig. 64A) with outer surface of merus covered with small granules on distal margin, outer margin straight, anteroexternal angle rounded; ischium squarish, distinctly longer and slightly broader than merus; exopod relatively stout. Chelipeds in male unequal, subequal in females (Figs. 61A, F, G, 63B), fingers of major chela smooth except for few tubercles hidden by row of long setae on dorsal surface of dactylus proximally, longitudinal ridge on dactylus and fixed finger; surface of palm pubescence, and with sparse long setae, outer lower surface of palm with tubercles continued to fixed finger proximally, cutting edges of fingers with prominent broad teeth; carpus and merus pubescence, margins covered with long setae; inner angle of carpus with sharp, denticulate protuberance (Fig. 63A). P2−P5 proportionally short (Figs. 62A, 63B), lateral surface, dorsal and ventral margins fringe with long setae; dactylus straight; merus of P5 not reaching front when folded. Fused thoracic sternites 1, 2 broadly triangular (Fig. 62D), proportionally narrow; thoracic sternites 3, 4 partially fused, with only lateral suture discernible. Male pleon (Figs. 62D, E, 64B) relatively broad; telson long, twice length of somite 6, subtriangular. G1 (Fig. 64 C–F) slender, slightly curved, upper half distinctly longer than lower half, distal part slightly sinuous, tip broad, pointed upward, with rows of setae near opening. Female pleon (Fig. 63C) broad, somite 1 reaching coxae of fourth ambulatory legs, tapering to pointed edge; telson subtriangular; vulva (Fig. 63D) relatively broad, ovate.   
 Etymology. From the Latin hirtus, hairy, in allusion to the long setae covering carapace, chelipeds and ambulatory legs.   
 Remarks. Typhlocarcinops hirtus n. sp. is superficially similar to T. tonsuratus from Australia, which is also a distinctly tomentose species. Typhlocarcinops hirtus n. sp. can be distinguished by its more transversely rectangular carapace with the width to length ratio 1.4‒1.5 (Figs. 62A, 63B) (versus carapace more squarish with the width to length ratio 1.2 in T. tonsuratus; Fig. 34A); the ischium of the third maxilliped is distinctly longer and slightly broader than the merus, with the inner and outer margins straight (Fig. 64A) (versus the ischium of the third maxilliped is only slightly longer than the merus, with the inner margin of the ischium slightly oblique in T. tonsuratus; Fig. 34B); and the G1 is slightly curved on the lower half, with the distal part sinuous, the tip broad and the opening has rows of setae setae (Fig. 64 C–F) (versus G1 strongly curved on lower half, the distal part gently curved upwards, the tip upcurved with two series of short and long setae distally in T. tonsuratus; Fig. 34 E–G).   
 The general carapace shape and degree of setation on T. hirtus n. sp. closely resembles Paraselwynia ursina Tesch, 1918, described from nearby Kei Islands in the Moluccas. The first author managed to examine the type female (and only known specimen) and it is refigured here (Figs. 65, 66) as the original drawings by Tesch (1918) are somewhat schematic. Typhlocarcinops hirtus n. sp. differs from Paraselwynia ursina in having the dorsal surface of the carapace almost flat (Fig. 62C) (versus prominently domed and convex in P. ursina; cf. Fig. 65C); the frontal margin is distinctly bilobed with convex lobes (Fig. 62B, C) (versus frontal margin almost straight and entire in P. ursina; cf. Fig. 65B, C); ischium of the third maxilliped is subrectanguar with the merus quadrate (Fig. 64A) (versus ischium of third maxilliped subtrapezoidal with the merus subovate in P. ursina; cf. Fig. 66A); the setae are concentrated on the dorsal margin of the dactylus of the chela with the pollex mostly glabrous (Fig. 62F, G) (versus both fingers of the chela covered with very dense setae which partially obscures the surfaces in P. ursina; cf. Fig. 65F, G); the female pleon is narrowly ovate with the telson acutely triangular (Fig. 63C) (versus female pleon broadly ovate with the telson semicircular in P. ursina; cf. Fig. 65D); and the vulvae are smaller and positioned closer to the median line (Fig. 63D) (versus vulvae relatively larger and positioned further apart in P. ursina; cf. Fig. 65E).   
 This is the only species of Typhlocarcinops known to live in the intertidal area, collected among seagrass in sandy mud substrate.   
 Type locality. Kuta, southern Lombok Island.   
 Distribution. Known only from Lombok Island, Indonesia, thus far.
description: Published as part of 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, pp. 1-100 in Zootaxa 4788 (1) on pages 75-78, DOI: 10.11646/zootaxa.4788.1.1, http://zenodo.org/record/3878222