Burmochlamys cauisa (Benson, 1859) comb. nov.

Fig. 6C

Helix cauisa Benson, 1859: 388. Type locality: Phie Than, vallis Tenasserim [Phie Than, Tenasserim Valley].

Helix causia [sic] - Pfeiffer, 1868: 118; Hanley and Theobald 1874: 37, pl. 90, figs 2, 3; Tryon 1887: 102, pl. 15, figs 67, 68.

Macrochlamys causia [sic] - Godwin-Austen, 1907: 163; Blanford and Godwin-Austen 1908: 117.

Macrochlamys cauisa - Pholyotha et al. 2020b: 186, 187, fig. 3a.

Material examined.

Type material. Tenasserim: probable syntypes UMZC I.102465.

Other material.

Kalryenmullay Hills, Tenasserim: NHMUK 1888.12.4.465- 466 ex. Blanford Coll. (two shells; Fig. 6C; specimen figured in Pholyotha et al. 2020b: fig. 3a).

Remarks.

Shell morphology of B. cauisa is matched well to this new genus rather than the depressed and lustrous shell of the Macrochlamys (see Pholyotha et al. 2020b). The unique shell morphology is subglobose, small size (width of ~ 7.0 mm, height of ~ 4.0 mm), obliquely striated and very minutely longitudinal lines, moderately elevated spire, enlarged and well-rounded last whorl, ovate lunate aperture, simple peristome, simple columellar margin with slightly reflected near umbilicus, and narrowly open umbilicus (Fig. 6C; Benson 1859; Blanford and Godwin-Austen 1908). Unfortunately, we could not find any specimens identifiable to this species during this survey.

Burmochlamys cauisa is currently known only from the type locality and vicinity of Salween River basin (Blanford and Godwin-Austen 1908). It is easy to distinguish from all other congeners by its moderately elevated spire and rather broad ovate lunate aperture. In comparison, most species of Burmochlamys gen. nov. have a higher shell spire and narrower aperture opening.