Anceyoconcha rhombostoma (Pfeiffer, 1861)

Sutcharit, Chirasak, Thach, Phanara, Chhuoy, Samol, Ngor, Peng Bun, Jeratthitikul, Ekgachai, Siriwut, Warut, Srisonchai, Ruttapon, Ng, Ting Hui, Pholyotha, Arthit, Jirapatrasilp, Parin & Panha, Somsak, 2020, Annotated checklist of the land snail fauna from southern Cambodia (Mollusca, Gastropoda), ZooKeys 948, pp. 1-46 : 1

Anceyoconcha rhombostoma (Pfeiffer, 1861) Figs 5D, E , 12C, D

Bulimus rhombostomus Pfeiffer, 1861: 194, 195. Type locality: Camboja [Cambodia].

Ganesella rhombostoma : Sutcharit et al. 2019a: 61-63, figs 1c, 3c-i, 5e-g, 7d-f.

Anceyoconcha rhombostoma : Nahok et al. 2020: 82-84, figs 2b, 3c, d, 4b, 6, 7b.

Material examined.

Locality no. 9: CUMZ-CM047 (66 shells), CUMZ-CM048 (5 shells; Fig. 12C ), CUMZ-CM049 (9 specimens in ethanol; Fig. 5D ). Locality no. 10: CUMZ-CM060 (4 shells). Locality no. 11: CUMZ-CM085 (8 shells; Fig. 12D ). Locality no. 12: CUMZ-CM113 (5 shells). Locality no. 13: CUMZ-CM132 (3 shells). Locality no. 17: CUMZ-CM139 (5 shells), CUMZ-CM140 (2 specimens in ethanol; Fig. 5E ). The snails were found to live on tree trunks and leaves.

Distribution.

Cambodia, Thailand and Vietnam ( Sutcharit et al. 2019a).

Remarks.

This species was originally described from Cambodia based on the Mouhot collection and was recently revised by Sutcharit et al. (2019a) and Nahok et al. (2020) based on Thai and Cambodian specimens. These recent specimens were collected from Kampot area, southern Cambodia and tend to be variable in size and shape compared to the type specimens (see Sutcharit et al. (2019a: fig. 3c, d) for the lectotype and paralectotype, respectively). They have smaller shell size and an ovate trochoid shell, with a large last whorl which is well-rounded and keeled on the periphery for nearly the entire last whorl (Fig. 12C, D indicated by an arrowhead). The aperture shape is trapezoid.

There is one subspecies " Buliminus rhombostomus var. pupoidea Dautzenberg & Fischer, 1905" described from "Cochinchine: Hong-Chon" [probably in the area of south Vietnam and Cambodia]. Unfortunately, the original description was brief, without measurements and illustrations, and the type specimen could not be located. Therefore, we could not assign the southern Cambodian specimens with certainty to this subspecific entity.

Figures

Figure 5. Living snails of A Amphidromus leucoxanthus (Martens, 1864) B Trichochloritis norodomiana (Morlet, 1883) C Ganesella perakensis (Crosse, 1879) D, E Anceyoconcha rhombostoma (Pfeiffer, 1861) D brownish morph and E dark brown morph and F Anceyoconcha chaudoensis (Rochebrune, 1881) comb. nov. All not to scale.

Figure 12. A Ganesella perakensis (Crosse, 1879) B Anceyoconcha siamensis obesula (Ancey, 1888) comb. nov. C, D Anceyoconcha rhombostoma (Pfeiffer, 1861). A white arrowhead indicates strong peripheral keel on the last whorl, the distinguished character of this species and E, F Anceyoconcha chaudoensis (Rochebrune, 1881) comb. nov.