Nassarius (Zeuxis) glabrus, Zhang & Zhang, 2014

Zhang, Junlong & Zhang, Suping, 2014, A new species of Nassarius (Gastropoda: Nassariidae) from the China seas, Raffles Bulletin of Zoology 62, pp. 610-614 : 611

Nassarius (Zeuxis) glabrus , new species

( Fig. 1A–C, G )

Nassarius (Zeuxis) algidus — Li et al., 2010: fig. 1g, i [non Reeve, 1853].

Type locality. South China Sea .

Material examined. Holotype: 1 shell (SL 16.1 mm × SW 9.5 mm) ( MBM062377 ), South China Sea, St. 6189, 17°00'N 109°30'E, 164 m, muddy bottom, R / V 101 , coll. Liu Jixing, 11 March 1960 . Paratypes: South China Sea: #1, 1 shell (SL 18.7 mm × SW 10.0 mm) ( MBM179987 ), St. 6079, 20°00'N 113°00'E, 128 m, in sandy bottom, R / V Hanggong I ,, coll. Ma Xiutong & Wang Yongliang, 20 October 1959 ; # 2, 1 shell (SL 15.6 mm × SB 8.3 mm) ( MBM179988 ), St. 32, 8°29.67'N 109°00.42'E, 143 m, in coarse sandy bottom, R / V Shiyan III, coll. Wang Shaowu, 17 September 1994 ; # 3, 1 shell (SL 17.9 mm × SW 9.8 mm) ( MBM179989 ), St. 17, 5°15.46'N 114°09.57'E, 173 m, in sandy mud bottom, R / V Shiyan III, coll. Chen Ruiqiu, 9 May 1987 ; # 4, 1 shell (SL 16.6 mm × SW 9.8 mm) ( MBM179990 ), St. 43, 5°27.66'N 110°16.12'E, 167 m, in sandy and muddy bottom, R / V Shiyan III, coll. Chen Ruiqiu, 15 May 1987 ; # 5, 1 shell (SL 10.6 mm × SW 6.1 mm) ( ZRC.MOL.5727 [ex MBM228998 ]), St. 36, 5°00'N 111°17'E, 110 m, in muddy bottom, R / V Shiyan III,, coll. Chen Ruiqiu, 14 May 1987 ; # 6, 2 shells (SL 14.5 mm × SW 8.7 mm; SL 14.0 mm × SW 8.1 mm) ( MBM179991 ), St. 32, 8°29.67'N 109°00.42'E, 143 m, in sandy bottom, R / V Shiyan III,, coll. Wang Shaowu, 17 September 1994 . East China Sea: #7, 1 shell (SL 17.3 mm × SW 9.7 mm) ( NHMUK 20140087 ), 1 shell (SL 17.3 mm × SW 9.8 mm) (MNHN-IM-2012-2764), 2 shells (SL 18.3 mm × SW 10.1 mm; SL 15.3 mm × SW 8.5 mm) ( HD 29396 ), 250 m, sand bottom, 2011; #8, 1 shell (SL 14.4 mm × SW 8.0 mm) ( HD 20989 ), 140–280 m, sand and mud bottom, June 2006 ; # 9, 3 shells (SL 17.3 mm × SW 9.6 mm; SL 15.8 mm × SW 8.3 mm; SL 14.7 mm × SW 8.2 mm) ( HD 20727 ), 150 m, sand bottom, June 2007 ; # 10, 1 shell (SL 17.4 mm × SW 9.2 mm) ( HD 32712 ), 120 m, on sand and mud, March 2013 .

Description. Shell elongate-ovate, small or moderately small, up to 18.7 mm in length, solid, with 7–8 whorls. Spire slender, whorls convex. Suture distinct, with a ledgelike and prominently keeled shoulder. Body whorl large and inflated. Protoconch comprises 2 glassy light brown whorls without axial ribs, and with a keel just above the suture. Shell surface glossy and smooth without sculpture apart from the first 2–3 spire whorls which bear distinct axial ribs crossed by weaker spirals. 3–4 spiral cords present at base of the body whorl. Shell light brown in colour, with faint irregular yellowish-brown flame-like patterns, and alternating reddish-brown and white marks at the sutural keel. Aperture ovate, interior light brown, without ribs; inner lip arc-shaped with slight callus. Columellar callus with few to numerous small plicae. Leading edge of outer lip thin, more thickened at the posterior side. A few axial ribs are located adjacent to the thickened dorsal side of the outer lip. Anterior canal broad and short, circled by 4–5 spiral grooves. Posterior canal thin and small.

Etymology. The species is named after its glossy and smooth shell. The specific name glabrus derived from Latin glaber, which means smooth.

Habitat. The new species has been found in muddy-sand and coarse sandy bottom at 110–280 m depth.

Distribution. Thus far known only from the South and East China seas. The South China Sea localities are indicated in Fig. 2 ; localities in the East China Sea have been omitted because of lack of data.

Discussion. Compared with Nassarius (Zeuxis) nanhaiensis Zhang, 2013 ( Fig. 1D–F, H ), Nassarius (Zeuxis) glabrus , new species, differs by its protoconch which is white in colour, its suture, and keeled shoulder. The suture of N. (Z.) nanhaiensis Zhang, 2013 is impressed, but the subsutural part of the whorls are gradual and not shouldered, the protoconch is brown, the spire is more pointed, and the surface has wide red-brown bands. Besides these morphological differences, the two species also appear to be restricted to different depths. Except for one specimen that was collected at a relatively deep 76 m, the other 15 specimens of N. (Z.) nanhaiensis were taken at shallow depths of 23– 38 m. In comparison, Nassarius (Z.) glabrus , new species, was collected only in waters deeper than 110 m, with 280 m being the greatest depth recorded.

Nassarius (Z.) glabrus , new species, also closely resembles N. (Z.) kooli Dekker & Dekkers, 2009 ( Fig. 1I, J ) morphologically, but it differs from the latter by its broader and shorter shell, more inflated body whorl, and colour and patterns of irregular yellowish-brown spots or stripes. Nassarius (Z.) kooli is more slender in shape, has a proportionally taller spire, deeply channeled suture, less inflated body whorl, and patterns of spiral bands, which are predominantly interrupted block-like blotches.

Nassarius (Z.) glabrus , new species, was figured by Li et al. (2010: fig. 1g, i) as N. (Z.) algidus ( Reeve, 1853) . However, the real N. (Z.) algidus ( Reeve, 1853) is a larger Australian species with different shell colour and patterns (see Cernohorsky, 1984; Wilson, 1994). The Nassarius (Zeuxis) sp. figured by Li et al. (2010: fig. 1f, h) is very close to our new species, but lacks the axial ribs on the first 2–3 teleoconch whorls. In the same study, Li et al. (2010: fig. 3) reported a large genetic difference between the specimens with and without these axial ribs, and the rachidians of the radula are also different ( Li et al., 2010: fig. 2). Although they still cluster together in their phylogenetic tree, we provisionally regard that species as not conspecific with Nassarius glabrus , new species, and further study is needed to determine their actual relationship.

Figures

Fig. 1. A–C, G, Nassarius glabrus, new species; D–F, H, Nassarius nanhaiensis Zhang, 2013; I, J, Nassarius kooli Dekkers & Dekker, 2009. Nassarius glabrus, holotype (MBM062377), SL 16.1 mm, South China Sea: A, apertural view; B, lateral view; C, dorsal view; G, protoconch. Nassarius nanhaiensis, holotype (MBM062273), SL 22.2 mm, South China Sea: D, apertural view; E, lateral view; F, dorsal view; H, protoconch. Nassarius kooli, holotype (ZMA Moll.04.09.053), SL 20.4 mm, Balicasag Island, Philippines: I, apertural view; J, dorsal view.

Fig. 2. Sampling stations of Nassarius glabrus, new species. The star-shaped symbol is used to indicate the locality of this species recorded by Li et al. (2010).