Typhlocarcinops stephenseni Serène, 1964

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 : 40-41

Typhlocarcinops stephenseni Serène, 1964

( Fig. 33 )

Typhlocarcinops nudus — Alcock, 1900: 322; Stephensen 1946: 173, figs. 48, 49A–H (not Typhlocarcinus nudus Stimpson, 1858 )

Typhlocarcinops stephenseni Serène, 1964: 223 , text-fig. 8, pl. 19B; Ng 1987: 78; Ng et al. 2008: 144.

Material examined. None

Diagnosis. Carapace ( Fig. 33A ) 1.4 times as broad as long, surface smooth, glabrous, regions indistinct; anterolateral margin arcuate, lined with tiny granules, with 2 obscure fissures. Front slightly bilobed, with shallow median cleft, margin of each lobe slightly convex. Orbit largerly oval almost subcircular. Third maxilliped ( Fig. 33B ) with anteroexternal angle of merus rounded, inner margins straight, ischium slightly broader, much longer than merus, inner margin shorter than outer margin, lower margin slightly oblique; exopod narrow, tip reaching to midlength of merus, inner margin with small, indistinct tooth. Chelipeds unequal ( Fig. 33A ), smooth, with sparse setae on upper, lower margins; upper outer surface of carpus smooth, inner angle with short low tooth. Male pleon ( Fig. 33C ) relatively narrow, telson short, 1.3 times as long as somite 6, subtriangular with rounded distal margin. G1 ( Fig. 33D, E ) slender, curved, upper and lower halves subequal, distal part strongly curved downwards, tip broad, fluted, with subdistal setae (adapted from Serène 1964).

Remarks. Serène (1964) referred specimens identified as “ Typhlocarcinus nudus Stimpson, 1858 ” by Alcock (1900) and Stephensen (1946) from the Indian Ocean to a new species, T. stephenseni . He examined and figured one male specimen 7.5 × 5.3 mm from the Indian Museum. Although he gave the catalogue number, Serène (1964) did not provide a locality. He only stated that it was one of Alcock’s (1900) specimens. Alcock (1900: 322) noted he had 25 specimens from “Karachi and the Mekran coast, Madras coast and Sandheads, and the Andamans”, so the origin of Serène’s specimen cannot be determined. Stephensen’s (1946: 173) material was from the Persian Gulf and Gulf of Oman. Serène (1964) did not designate any specimen as a holotype so all of Alcock’s (1900) and Stephensen’s (1946) specimens are syntypes and a lectotype should be selected at a later date.

Serène (1964) was unsure about Rathbun’s (1910: 343) specimens of “ Typhlocarcinus nudus ” from the Gulf of Thailand and Singapore and suggested that they may also be his new species. No material of T. stephenseni from Southeast Asia was confirmed for the present study and consequently this species was excluded from the region for the time being.

Type locality. Indian Ocean.

Distribution. Indian Ocean.

Figures

FIGURE 33. Typhlocarcinops stephenseni Serène, 1964, lectotype male (7.5 × 5.3 mm) (Zoological Survey of India no. 4.991), Indian Ocean. A, overall habitus; B, left third maxilliped; C, pleon; D, left G1 (dorsal view); E, distal part of left G1 (ventral view). After Serène (1964: text-fig. 8, pl. 19 fig. B). Scales: B, C = 1.0 mm; D = 0.3 mm; E = 0.2 mm.