Curvella Chaper, 1885

Man, Nem Sian, Ablett, Jonathan D., Lwin, Ngwe, Sutcharit, Chirasak & Panha, Somsak, 2024, Contributions on a small collection of the former Subulinidae Fischer & Crosse, 1877 (Eupulmonata, Achatinoidea) with catalogue of the Glessula and Rishetia species recorded from Myanmar, ZooKeys 1208, pp. 173-239 : 173-239

Genus Curvella Chaper, 1885

Bulimus (Hapalus) Albers, 1850: 140. [non Illiger 1801 (Coleoptera)]. Type species Bulimus grateloupi Pfeiffer, 1846. Albers 1860: 238.

Curvella — Chaper, 1885: 49. Pilsbry 1906: 46. Gude 1914: 348. Zilch 1959: 351. Schileyko 1999: 515. Budha et at. 2017: 120.

Type species.

Curvella sulcata Chaper, 1885 , by original designation in Chaper (1885: 48).

Diagnosis.

Shell oblong-conical; spire low or high and rapidly attenuated; embryonic whorls smooth; subsequent whorls with equally or irregularly spaced thick or fine radial striations or ribs. Aperture vertical, broad-ovate, or oblong, and somewhat pointed above; columella straight; columellar margin expanded near umbilicus. Penis simple and short papillate or short tube; epiphallus and flagellum absent; vagina large, muscular, and nearly equal to penis length.

Remarks.

Curvella is clearly distinct from other subulinid genera such as Allopeas , Bacillum , and Opeas by its oblong-conical shell, short spire, high and wide aperture, and its much broader last whorls (Table 2 ). Regarding the genitalia, this genus displays a more rounded, muscular, short penis and a thicker vagina than Allopeas and Opeas ( Schileyko 1999) . In comparison, the two latter genera have a slender, narrow, more elongated penis and vagina compared to Curvella ( Schileyko 1999; Budha 2017). However, only genitalia of Curvella sikkimensis (Reeve, 1850) is known for this genus at present ( Budha 2017).

This genus is widely distributed from Africa to South Asia and China, and ~ 95 species have been reported ( Pilsbry 1906; Gude 1914; Schileyko 1999; Ramakrishna et al. 2010; Budha et al. 2017; MolluscaBase 2023). There are scattered reports of four Curvella species in Myanmar, while one species, C. tonkiniana Jaeckel, 1950 , has been reported in Vietnam and one species, C. jousseaumei ( de Morgan, 1885) , from Peninsular Malaysia ( Gude 1914; Maassen 2001; Schileyko 2011; Vermeulen et al. 2015).