Nephropsis grandis Zarenkov, 2006

Chang, Su-Ching, Chan, Tin-Yam & Kumar, Appukuttannair Biju, 2020, Deep-sea clawed lobster Nephropsis stewarti Wood-Mason, 1872 species complex in the Indo-West Pacific (Crustacea, Decapoda, Nephropidae), with description of a new species, ZooKeys 1008, pp. 37-60 : 37

Nephropsis grandis Zarenkov, 2006 Figures 2 , 5A, B

Nephropsis grandis Zarenkov 2006: 86, figs 5-7 (type locality: Arafura Sea).

Nephropsis stewarti .- Kubo 1965: 629, unnumbered fig.; Miyake 1982: 77, pl. 26-1; Baba 1986: 153, fig. 103; Chan and Yu 1988: 8, pl. 1A; 1993: 83, unnumbered photo; Holthuis 1991: 45 (in part); Wadley and Evans 1991: 39, unnumbered photo; Macpherson 1993: 63; Chan 1997: 415; Jones and Morgan 2002: 83, unnumbered photo; Davie 2002: 391; Zarenkov 2006: 93 (in part), fig. 19; Chang and Chan 2019: 50 (in part), fig. 7. [not Wood-Mason 1872].

Nephropsis stewarti ? Nephropsis stewarti .- Macpherson 1990: 312 (in part). [not Wood-Mason 1872].

Material examined.

Neotype: Indonesia • male cl 64.1 mm; Tanimbar Islands, Arafura Sea, Karubar stn CP59, 08°20'S, 132°11'E, 405-399 m, 31 Oct 1991 (MNHN IU-2017-9001).

Other material.

Japan • 1 male cl 43.5 mm; Suruga Bay, off Numazu, commercial trawler, 34°44.37'N, 138°41.13'E, 350 m, 20 Apr. 2016 (CBM-ZC 14212) • 1 male cl 46.0 mm, 1 female cl 36.0 mm; Tosa Bay, off Mimase, 16 Jan.-14 Feb. 1963 (SMF 18328) • 2 males CL 32.0, 41.0 mm, 1 female cl 27.5 mm; 1961-1963 (SMF 24678). TAIWAN • 1 female cl 44.8 mm; Dasi fishing port, Yilan County, commercial trawlers, 10 Sept. 1984 (NTOU M02165) • 1 male cl 45.3 mm, 2 females cl 39.7 and 39.8 mm; Sept. 1992 (NTOU M02171) • 1 male cl 38.9 mm; Aug. 2003 (NTOU M00505) • 1 male cl 41.9 mm; 29 May 2008 (NTOU M02177) • 1 female cl 32.4 mm; 12 Apr. 2012 (NTOU M02178) • 1 male cl 19.8 mm; 14 Aug. 2013 (NTOU M02179) • 1 male (carapace damaged), 1 female cl 40.7 mm; Nanfang-ao fishing port, Yilan County, commercial trawlers, 2 May 1985 (NTOU M02166) • 1 male cl 28.2 mm, 1 female cl 40.5 mm; 20 Apr. 1988 (NTOU M02167) • 1 male cl 31.8 mm; 12 Nov. 2004 (NTOU M02176) • 2 males cl 29.0 and 32.7 mm; Donggang fishing port, Pingtung County, commercial trawlers, 27 Dec. 1997 (NTOU M02174) • 1 male cl 31.1 mm, 2 females cl 30.2 and 40.6 mm; locality not specified, 1993 (NTOU M02172). South China Sea • 1 female cl 45.9 mm; Dongsha (Pratas), Jun. 1991 (NTOU M02170) • 1 male cl 15.9 mm; Zhongsha 2015 stn CP4137, 19°53.059'N, 114°21.678'E, 536-524 m, 23 Jul. 2015 (NTOU M02161) • 1 male cl 12.8 mm; stn CP4155, 16°13.60'N, 115°01.61'E, 526-510 m, 28 Jul. 2015 (NTOU M02163). Philippines • 1 female cl 32.0 mm; PANGLAO 2005 stn CP2384, 8°46.2'N, 123°16.1'E, 647-613 m, 29 May. 2005 (NTOU M02251). Indonesia • 1 female cl 51.1 mm; Tanimbar Islands, Arafura Sea, Karubar stn CP39, 07°47'S, 132°26'E, 477-466 m, 28 Oct. 1991 (MNHN IU-2017-9002) • 1 female cl 25.4 mm; stn CP59, 08°20'S, 132°11'E, 405-399 m, 31 Oct. 1991 (MNHN IU-2018-5062). North West Australia • 1 male cl 53.7 mm; 18°19'S, 117°149'E, 25 Feb. 1986 (NTOU M02252).

Diagnosis.

Rostrum armed with a single pair of lateral teeth usually situated posterior to mid-length of rostrum. Carapace with subdorsal carinae granulate, lacking distinct spine; supraorbital and antennal spines present; post-supraorbital spine absent; postcervical groove U-shaped in dorsal view; intermediate carina weak, indistinct. Large cheliped (pereiopod I) with inner surface of palm usually armed with row of distinct spines; carpus with strong distoventral, ventro-outer distal, and dorso-inner distal spines, inner surface usually with 2-4 spines along dorsal margin and several small spines on ventral margin, both dorsal and ventral margins of outer surface spinose; merus with subdistal dorsal and anteroventral spine, generally also bearing a spine or sharp tubercle on subdistal outer surface. Pleon generally smooth and lacking mid-dorsal carina; pleura each with unarmed anterior margin. Telson without erected mid-dorsal spine near base. Uropodal exopods with complete diaeresis.

Description.

Body covered with long or short pubescence, rather thick on dorsal carapace, pleonal tergites and anterior two pereiopods. Carapace finely granulated (Fig. 2A, B ); rostrum 0.4-0.8 × as long as carapace (proportionally longer in small individuals), bearing 1 pair of lateral teeth usually situated posterior to mid-length of rostrum; subdorsal carinae granulate, lacking distinct spine; strong supraorbital and antennal spines present; post-supraorbital spine absent; cervical, postcervical, and hepatic groove well-marked, with post-cervical groove U-shaped in dorsal view; intermediate carina weak, indistinct; lateral carina distinct; distance between gastric tubercle and supraorbital spines 0.3-0.4 × distance between gastric tubercle and postcervical groove; distance between orbital margin and postcervical groove 1.3-1.5 (rarely 1.6) × distance between post-cervical groove and posterior margin of carapace.

Large cheliped (pereiopod I), generally with smooth surface (Fig. 2C-E ); chela 2.7-4.7 (mostly 2.9-3.8) × as long as wide; inner surface of palm generally armed with row of distinct spines except for very small individuals; carpus with strong distoventral spine, ventro-outer distal spine, and dorso-inner distal spine, inner surface having 2-4 spines (sometimes only one in very small individuals) along dorsal margin and several small spines on ventral margin, both dorsal and ventral margins of outer surface spinose (with fewer spines in small young specimens); merus with subdistal dorsal spine and distoventral spine, usually also bearing subdistal outer spine or sharp tubercle. Pereiopod II with carpus 0.5-0.7 (rarely 1) × palm length. Pereiopod III with carpus 0.4-0.5 × as long as palm; merus 1.8-2.1 × longer than carpus. Pereiopods IV and V with dactyli 0.3-0.6 × as long as propodi.

Pleon generally smooth (Fig. 2A, B ), lacking median carina, only tergites I and VI granulate; pleura each with unarmed anterior margin and each terminating ventrally into a blunt or sharp spine. Telson without erected dorsal median spine near base. Uropodal exopods with complete diaeresis.

Eggs spherical and approximately 3 mm in diameter ( Chan and Yu 1988).

Distribution.

Western Pacific and northwestern Australia, known with certainty from Japan, Taiwan, South China Sea, the Philippines, Indonesia (Kai and Tanimbar Islands), Arafura Sea, and northern Australia (Queensland to NW Shelf); at depths of 312-647 m ( Macpherson 1993; present study) and perhaps 170-821 m (see Remarks).

Color in life.

Body, including eyes, generally whitish, pubescence grayish to grayish brown (Fig. 5A, B ; Miyake 1982: pl. 26-1; Baba 1986: fig. 103; Chan and Yu 1988: pl. 1A; 1993: unnumbered photo; Wadley and Evans 1991: unnumbered photo; Jones and Morgan 2002: unnumbered photo). Rostrum and antennal flagella orange to reddish, sometimes anterodorsal carapace also orange. Antennular flagella whitish to reddish. Maxilliped III and pereiopods II to V white to orange-pink and with distal parts reddish. Large cheliped whitish to somewhat orange. Pleopods and margins of pleonal pleura whitish or reddish. Uropods and distal part of telson pinkish red to reddish. Eggs whitish ( Chan and Yu 1988).

Remarks.

Although the western Pacific and northwestern Australia material has been shown to be not the true N. stewarti , molecular genetic analysis suggests that there are two distinct species (16S sequence divergence as high as 7.5-9.4%, even higher than 3.1-6.3% among N. serrata , N. aculeata , and N. rosea ; Table 2 ). Careful comparisons revealed that these two genetic forms differ, detailed as follows. (1) The body size is large in one form (up to cl 64.1 mm, MNHN IU-2017-9001) but much smaller in the other (up to cl 28.0 mm NTOU M02259). (2) Although the pleon is concealed by thick pubescence, the surfaces of tergites II to V is rather smooth in the large size form (Fig. 2A, B ) but distinctly granular in the smaller form (Fig. 3A, B ). (3) The large cheliped is also concealed by long pubescence but is more spiny in the large form. In the large form, the carpus is heavily spinose on the outer surface and has 2-4 spines along the dorsal margin of the inner surface (Fig. 2C-E ). The inner surface of the palm is also spiny (Fig. 2C, E ), except in small young specimens (cl <20 mm), and the merus generally has a subdistal outer spine or sharp tubercle (Fig. 2C, D ) except in one female (MNHN IU-2018-5062). For the large cheliped of the smaller form, the carpus has an outer surface without distinct spines and the inner surface bears only one (mostly) or two spines on the dorsal margin (Fig. 3C-E ). The inner surface of the palm lacks distinct spines (Fig. 3C, E ), and there is no subdistal outer spine or sharp tubercle on the merus (Fig. 3C, D ).

Nephropsis grandis was described from a single male collected near the Tanimbar Islands in the Arafura Sea (09°07.5'S, 131°14.9'E, Zarenkov 2006). The holotype is a large specimen (carapace length, including rostrum, 58 mm) and its pleonal tergites I-VI are without granules on the surfaces. The large cheliped in the holotype appears to be rather spinous; however, it is difficult to comprehend the exact spination on the various parts from the original description and illustrations. For example, the holotype appears to lack a subdistal outer spine at the merus of the large cheliped ( Zarenkov 2006: table 1: subdistal spine on outer surface of merus of cheliped). Nonetheless, the larger form discussed above generally fits the characteristics described for N. grandis , and at present, only the larger form is found in the Arafura Sea. Currently, the holotype of N. grandis (ZMMU Ma 5157) cannot be located in the Zoological Museum of Moscow University (V Spiridonov, personal communication). As there are now three species in the N. stewarti species complex and each has only subtle differences, it is desirable to fix the identity of N. grandis . The current largest specimen (MNHN IU-2017-9001) from the Tanimbar Islands, and with genetic data available, was selected as the neotype of N. grandis , thus affixing this name on the larger form in the West Pacific and northwestern Australia. The neotype was collected from a locality very close to that of the holotype (both in the Arafura Sea) and is generally similar to the original figures provided for the holotype (Fig. 2A-C ; Zarenkov 2006: figs 5, 6).

Nephropsis grandis is genetically distinct from N. stewarti , with 6.4-7.3% 16S sequence divergence (Table 2 ). Other than the differences described under the “Remarks” of N. stewarti , these two species also differ in the pleonal tergites II-V, being smooth in N. grandis (Fig. 2A, B ) but granular in N. stewarti (Fig. 1A, B ). In Nephropsis grandis the outer surface of the large cheliped carpus is spinose (Fig. 2C-E ) but this is only granular and without distinct spines in N. stewarti (Fig. 1C-E ). In large specimens, the inner surface of palm of the large cheliped is also spinose in N. grandis (Fig. 2C, E ) but still lacks spines in N. stewarti (Fig. 1C, E ). Macpherson (1993) suggested that the shape of the large chela might be different among the species in the N. stewarti species complex. However, this is not supported by the present work, even though the large chelae have sexual dimorphism only in N. stewarti .

Nephropsis grandis is widely distributed from Japan to Australia. Photographs of the Japanese specimen identified as " N. stewarti " from Suruga Bay (CBM-ZC 14212) and with a very short 16S sequence for eDNA metabarcoding (LC430805, 163 bp; Komai et al. 2019) is now confirmed to represent N. grandis . The short 16S sequence of this specimen is also identical to the sequence of the present Taiwanese specimens (NTOU M02174, NTOU M00505) assigned to N. grandis . The Japanese specimens (SMF 18328), referred to " N. stewarti " by Zarenkov (2006), are rather small (two males and one female, cl, including rostrum, 32-41mm) but still have a distinct spine on the outer surface of the carpus of the pereiopod I ( Zarenkov 2006: fig. 19A); therefore, they likely represent N. grandis instead. The SMF 18328 lot, however, consists of two moderately large specimens (cl 36.0 mm and 46.0 mm). One more lot of " N. stewarti " from Japan is held in the Senckenberg Museum (SMF 24678), and there are three specimens within the lot. Although the number and sex of the specimens in the SMF 24678 lot match those reported for SMF 18328 in Zarenkov (2006), their sizes (cl 27.5-41.0 mm) do not match. Nevertheless, photographs of all five of these Japanese specimens in the Senckenberg Museum clearly show that they are all N. grandis because of the weak intermediate carina, large cheliped with distinct spines on the outer surface of the carpus, and the merus having subdistal outer spine. For the published photographs of Japanese " N. stewarti ", the one of Baba (1986: fig. 103) clearly shows the large cheliped with the inner surface of the palm and the outer surface of the carpus bearing distinct spines. The other photograph of Miyake (1982: pl. 26-1) also shows the large cheliped with the outer surface of the carpus armed with distinct spines, although the spination on the inner surface of the palm is unclear because of the covering of thick pubescence. Thus, it appears that only N. grandis is distributed in Japan among the N. stewarti species complex. Among the two sequenced Taiwanese specimens of this species, specimen NTOU M00505 was used in a clawed lobster phylogenetic study (Tshudy et al. 2009) as " N. stewarti " with GenBank no. EU882882, which has a sequence identical to U96086 from a specimen of N. stewarti in Natal, South Africa (Tam and Kornfield 1988). However, re-amplification of the 16S gene of the NTOU M00505 specimen (GenBank no. M302004) revealed that its sequence does not match EU882882 and belongs to the clade of N. grandis instead.

The present work revealed that among the N. stewarti species complex, both N. grandis and N. pygmaea sp. nov. are distributed in southern Taiwan and the Philippines, and the true N. stewarti is restricted to the Indian Ocean. Re-examination of the Philippines material (with a depth range of 170-821 m) reported as " N. stewarti " in Macpherson (1990) is necessary to determine which of these two species they belong to, and whether N. grandis can be found in waters as shallow as 170 m and/or as deep as 821 m.

Figures

Figure 1. Nephropsis stewarti Wood-Mason, 1872, Andaman Sea, RV ' Dr. Fridtjof Nansen' stn 135, neotype male cl 46.2 mm (NTOU M 02249) A carapace and pleon, dorsal B same, lateral C left pereiopod I, chela to distal part of merus, dorsal D same, lateral E same, ventral. Pubescence and setae omitted ● Position of spines on inner surface of palm ◇ position of spines on dorsal margin of outer surface of carpus ♦ position of spines on dorsal margin of inner surface of carpus ⏹ dorso-inner distal spine of carpus △ ventro-outer distal spine of carpus ◻ distoventral spine ✰ subdistal dorsal spine of merus ★ position of subdistal outer spine of merus.

Figure 2. Nephropsis grandis Zarenkov, 2006, Tanimbar Islands, Arafura Sea, KARUBAR stn CP 59, neotype male cl 64.1 mm (MNHN IU- 2017 - 9001) A carapace and pleon, dorsal B same, lateral C left pereiopod I, chela to distal part of merus, dorsal D same, lateral E same, ventral. Pubescence and setae omitted ● Position of spines on inner surface of palm ◇ position of spines on dorsal margin of outer surface ♦ position of spines on dorsal margin of inner surface ⏹ dorso-inner distal spine of carpus △ ventro-outer distal spine of carpus ◻ distoventral spine ✰ subdistal dorsal spine of merus ★ position of subdistal outer spine of merus.

Figure 3. Nephropsis pygmaea sp. nov., Donggang, Pingtung County, Taiwan, holotype male cl 25.6 mm (NTOU M 01898) A carapace and pleon, dorsal B same, lateral C left pereiopod I, chela to distal part of merus, dorsal D same, lateral E same, ventral, pubescence and setae omitted ● position of spines on inner surface of palm ◇ position of spines on dorsal margin of outer surface ♦ position of spines on dorsal margin of inner surface ⏹ dorso-inner distal spine of carpus △ ventro-outer distal spine of carpus ◻ distoventral spine ✰ subdistal dorsal spine of merus, ★ position of subdistal outer spine of merus.

Figure 5. A, B N. grandis Zarenkov, 2006, Dasi fishing port, Taiwan, male cl 45.3 mm (NTOU M 02171) C, D N. pygmaea sp. nov., Donggang fishing port, Taiwan, paratype female cl 24.4 mm (NTOU M 02168) A, C dorsal habitus B, D lateral habitus.