Opisthoporus beddomei Dautzenberg & Fischer, 1908

Sang, Do Duc, Chinh, Bui Thi & Nhuong, Do Van, 2020, The land snail genus Opisthoporus Benson in L. Pfeiffer, 1851 (Gastropoda: Caenogastropoda: Cyclophoridae) from Vietnam, with description of a new species, Raffles Bulletin of Zoology 68, pp. 103-111 : 104-105

Opisthoporus beddomei Dautzenberg & Fischer, 1908

( Figs. 1 , 2 A–D, 3A, D, G; Table 1, 2)

Opisthoporus beddomei Dautzenberg & Fischer, 1908: 200 , pl. 7

figs. 1–4 (type locality: Quang-Huyen , Vietnam). Cyclotus (Opisthoporus) beddomei – Kobelt, 1913: 836, pl. 124

figs. 1–4.

Material examined. 7 shells ( LZ–HUE 1021 ), 5 shells ( ZMHU), 2 figured shells (figs. 2A, B, 3A, D, G), Vietnam, Thua Thien Hue Province , Nam Dong District , Thuong Quang Commune, Limestone hill, 215 m a.s.l., 16°06′51″N, 107°38′27″E, coll. T.C. Bui, 16 September 2017 ; 3 shells ( LZ–HUE 1022 ), Vietnam, Thua Thien Hue Province , Nam Dong District , Thuong Quang Commune, Limestone hill, 111 m a.s.l., 16°07′08″N, 107°37′20″E, coll. T.C. Bui, 10 July 2018 .

Diagnosis. Shell brownish grey with numerous, rather regularly spaced growth lines that form distinct axial lines. Breathing tube curved towards the antepenultimate whorl.

Distribution. Opisthoporus beddomei is known from northern and central Vietnam (Cao Bang and Thua Thien Hue Provinces) ( Dautzenberg & Fischer, 1908; this study).

Remarks. Opisthoporus beddomei is characterised by a medium-sized thin shell, with corneous and translucent periostracum, and a surface that has a brownish grey colour pattern. Like its congeners, the last part of its last whorl is usually slightly detached from the penultimate whorl. This species is most similar to O. lubricus , although they differ slightly in terms of shell colouration. Both species have similar aperture morphology with the double peristome and white lip, although O. beddomei has a less prominent expansion on the upper part of its lip. The most distinctive difference between the two is the breathing tube, which is curved towards the antepenultimate whorl in O. beddomei and upright or curved forward towards the aperture in O. lubricus .

Its type locality Quang-Huyen most probably refers to Quang Uyen District in Cao Bang Province, although this species was not present in samples collected from surveys conducted in north Vietnam . Our discovery of this species from Thua Thien Hue, shell width of up to 20.0 mm, represents a range extension and the first record of Opisthoporus beddomei in central Vietnam.

Figures

Fig. 1. Approximate localities of Opisthoporus spp. in Vietnam. (1): Opisthoporus beddomei; (2): Opisthoporus lubricus; (3): Opisthoporus thuathienhuensis, new species. The numbered locality names are detailed in Table 1.

Fig. 2. Shell (apertural view, dorsal view, ventral view, and side view) and operculum (outer surface, inner surface, and side view) of Opisthoporus spp. in Vietnam. A–D, Opisthoporus beddomei Dautzenberg & Fischer, 1908; A, B, ZMHU/5; C, from Dautzenberg & Fischer, 1908; D, from Kobelt, 1913. E–G, Opisthoporus lubricus Dautzenberg & Fischer, 1908; E, ZMHU/4; F, from Kobelt, 1913; G, from Dautzenberg & Fischer, 1908. H–K, Opisthoporus thuathienhuensis, new species; H, I, holotype VNMN_IZ 000.000.176; J, K, paratypes ZRC.MOL. 15631. Photographs by D.S. Do and T.S. Nguyen.