Nephropsis stewarti Wood-Mason, 1872

Chang, Su-Ching & Chan, Tin-Yam, 2019, On the clawed lobsters of the genus Nephropsis Wood-Mason, 1872 recently collected from deep-sea cruises off Taiwan and the South China Sea (Crustacea, Decapoda, Nephropidae), ZooKeys 833, pp. 41-58 : 41

Nephropsis stewarti Wood-Mason, 1872 Figs 2C, D, 7

Nephropsis stewarti Wood-Mason, 1872: 60 (type locality: Ross Island, Andaman Sea); Chan and Yu 1988: 8, pl. 1A; 1993: 83, unnumbered photo; Macpherson 1990: 312, figs 5e, 10, 11c, d, 16e; 1993: 63; Holthuis 1991: 45, figs 80, 81; Chan 1997: 415; 2010: 157; Zarenkov 2006: 93, fig. 19; Poore et al. 2008: 34.

Nephropsis grandis Zarenkov, 2006: 86, figs 5-7 (type locality: off Arnhem Land, northern Australia).

Material examined.

Zhongsha 2015, stn CP4137, 19°53.059'N, 114°21.678'E, 536-524 m, 23 Jul 2015, 1 male cl 15.9 mm (NTOU M02161); stn CP4155, 16°13.60'N, 115°01.61'E, 526-510 m, 28 Jul 2015, 1 female cl 25.2 mm (NTOU M02162), 1 male cl 12.8 mm (NTOU M02163). Yilan County, Dasi fishing port, 10 Sept 1984, 1 female cl 44.8 mm (NTOU M02165); Sept 1992, 2 females cl 39.7, 39.8 mm, 1 male cl 45.3 mm (NTOU M02171); Aug 2003, 1 male cl 38.9 mm (NTOU M00505); 29 May 2008, 1 male cl 41.9 mm (NTOU M02177); 12 Apr 2012, 1 female cl 32.4 mm (NTOU M02178); 14 Aug 2013, 1 male cl 19.8 mm (NTOU M02179). Yilan County, Nanfang-ao fishing port, 2 May 1985, 1 female cl 40.7 mm, 1 male with damaged carapace (NTOU M02166); 20 Apr 1988, 1 female cl 40.5 mm, 1 male cl 28.2 mm (NTOU M02167); 12 Nov 2004, 1 male cl 31.8 mm (NTOU M02176). Pingtung County, Donggang fishing port, Jul 1975, 1 male cl 23.4 mm (NTOU M02164); 3 Mar 1991, 6 females cl 19.5-20.2 mm, 1 male cl 21.1 mm (NTOU M02168); 14 May 1991, 2 males cl 19.2, 21.7 mm (NTOU M02169); 4 Jun 1995, 1 male cl 22.4 mm (NTOU M02173); 27 Dec 1997, 2 males cl 29.0, 32.7 mm (NTOU M02174), 1 male cl 21.8 mm (NTOU M02175); 2 Oct 2014, 1 male cl 25.6 mm (NTOU M01898). Taiwan, locality not specified, 1993, 2 females cl 30.2, 40.6 mm, 1 male cl 31.1 mm (NTOU M02172). Dongsha, Jun 1991, 1 female cl 45.9 mm (NTOU M02170).

Diagnosis.

Carapace nearly smooth, sometimes with some granules. Rostrum with pair of lateral spines. Median groove overreaching lateral rostral spines. Subdorsal carinae granulate, without spines. Supraorbital spines well developed, without post-supraorbital spine. Distance between orbital margin and postcervical groove more than 1.5 times distance between postcervical groove and posterior margin of carapace.

Abdominal tergites II–V without dorsal median carina. No spines on anterior margin of each pleuron. Anterior margin of pleuron II convex, generally ending in long, sharp point (but rather short and blunt in large specimens). Anterior margins of pleura III–V less convex, each ending in long, sharp point. Uropodal exopod with distinct and complete diaeresis.

Cheliped I densely pubescent. Carpus with anterodorsal and anteroventral spines, and 0-4 dorsal spines on outer margin. Carpus of pereiopod II slightly shorter than palm. Carpus of pereiopod III more than half palm length. Dactyli of pereiopods IV and V approximately half propodus length.

Color in life.

Body generally whitish with antennular and antennal flagella, anterior segment of large chelae, dorsal carapace, and abdomen somewhat pale orange. Rostrum, tips of pereiopods II to V, and tail fan pinkish red. Eyes whitish. Pubescence on body light grey and eggs whitish.

Distribution.

Widely distributed in the Indo-West Pacific and has been reported from Madagascar, Natal, Mozambique, Kenya, Gulf of Aden, Andaman Sea, Bay of Bengal, Indonesia, Australia, the Philippines, Japan, Taiwan, and now the South China Sea, at depths of 170 to more than 1060 m ( Macpherson 1990, 1993; Chan 1997; Zarenkov 2006; Poore et al. 2008).

Remarks.

The present material collected by Taiwanese research vessels were from the South China Sea; near Dongsha (NTOU M02161, M02170) or the center of the South China Sea (NTOU M02162, M02163).

Nephropsis grandis Zarenkov, 2006 was described based on a single specimen from northern Australia, and is extremely similar to N. stewarti in the subdorsal carina lacking a spine and the abdomen without any dorsal median carina. These two species were differentiated only by the carpus of the large cheliped, which is more spiny in N. grandis (cf. Zarenkov 2006: table 4). As there are generally large intraspecific variations in the spination on the large cheliped in Nephropsis (e.g., in the present abundant material there are 4-15 distinct spines on the carpus of the large cheliped), more comprehensive studies with molecular genetic comparisons are necessary to verify if large cheliped spination is indeed a good character in separating the species of this genus. Therefore, for the time being N. grandis is treated as a synonym of N. stewarti as stated by Chan (2010).