Nephropsis holthuisi Macpherson, 1993

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 holthuisi Macpherson, 1993 Figs 1E, F, 5

Nephropsis holthuisi Macpherson, 1993: 55, figs 1-3 (except fig 3B), fig. 6B (erroneously as N. serrata ) (type locality: Ashmore Reef, northwest Australia); Griffin and Stoddart 1995: 234; Chan 1997: 414; 2010: 157; Watabe and Iizuka 1999: 372, figs 1, 2; Poore 2004: 166, fig. 43c.

Nephropsis macphersoni Watabe & Iizuka, 1999: 376, figs 3, 4 (type locality: east of Terrigal, southeastern Australia); Poore 2004: 166, fig. 43d.

Material examined.

TAIWAN 2001, stn CD132, 22°20.98'N, 120°6.73'E, 690-700 m, 21 Nov 2001, 1 female cl 18.7 mm (NTOU M02159). TAIWAN 2003, stn CP214, 24°28.59'N, 122°12.66'E, 490-1027 m, 27 Aug 2003, 1 female cl 11.3 mm, 3 males cl 13.6-14.1 mm (NTOU M02158); 1 male cl 15.2 mm (NTOU M02160).

Diagnosis.

Carapace sparsely granulate. Rostrum 0.6-0.8 times carapace length, with pair of lateral spines. Median groove on rostrum reaching or overreaching lateral rostral spines. Subdorsal carinae with 1-4 spines posterior to supraorbital spines. Supraorbital spine well-developed, followed by distinct post-supraorbital spine. Distance between level of supraorbital spine and gastric tubercle approximately 0.4 times the distance between gastric tubercle and postcervical groove. Postcervical groove passing dorsal midline of carapace. Distance between orbital border and postcervical groove 1.5-1.9 times distance between postcervical groove and posterior border of carapace.

Abdominal tergites II–VI with distinct dorsal median carina. Anterior border of each pleuron spineless, more convex in pleuron II, and terminating in long, sharp point on pleura II–V. Uropodal exopod with complete diaeresis.

Cheliped I sparsely granulate. Carpus shorter than palm, with anterodorsal spine, a spine on inner dorsal border at midlength, and without any accessory spines or granules. Carpus of pereiopod II somewhat shorter than palm. Carpus of pereiopod III 0.6 times palm length. Dactyli of pereiopods IV and V approximately half propodus length.

Color in life.

Body generally vermilion red, with dorsal surface of posterior carapace and abdomen pinkish orange. Tips of large chelae and eyes whitish.

Distribution.

Indo-West Pacific: Indonesia, Australia, Japan, and now Taiwan, at depths of 350-1135 m ( Macpherson 1993; Griffin and Stoddart 1995; Chan 1997; Watabe and Iizuka 1999; Poore 2004).

Remarks.

This species is similar to Nephropsis rosea Bate, 1888 from the West Atlantic. They both have one pair of rostral lateral spines, one pair of post-supraorbital spines, a median carina on tergites II–VI, and a complete diaeresis on uropodal exopods. These two species mainly differ in the position of the gastric tubercle (see Macpherson 1993). The Taiwanese material fits the characteristics of N. holthuisi in the distance between the supraorbital spine and gastric tubercle being less than half (vs. approx. 2/3 in N. rosea ) the distance between the gastric tubercle and postcervical groove. Watabe and Iizuka (1999) argued that N. holthuisi can be readily distinguished from N. rosea by the large spine at the midlength of the inner dorsal border of carpus of cheliped I does not have any accessory spines or granules (vs. 1-3 accessory spines in N. rosea ). The present specimens also agree in this character.

There are variations in the development of the subdorsal spines in the type series of N. holthuisi from rather granulate in the holotype to distinct in the paratype ( Macpherson 1993). The present six specimens from Taiwan all have 1-4 distinct spines on the subdorsal carina (Figs 1F, 5). Watabe and Iizuka (1999) considered such difference as specific and treated the paratype of N. holthuisi as a distinct species N. macphersoni Watabe & Iizuka, 1999. However, all other differences proposed to distinguish N. macphersoni from N. holthuisi by Watabe and Iizuka (1999), such as pereiopods "less pubescent" or "more robust", abdominal tergite "more strongly granulated", are rather vague. Therefore, for the time being N. macphersoni is treated as a synonym of N. holthuisi as already stated by Chan (2010) until more evidence (e.g., from molecular analysis) is available to support that the former is a distinct species.