Uncovering local endemism from southeastern Myanmar: description of the new karst-associated terrestrial snail genus Burmochlamys (Eupulmonata, Helicarionidae) Author Pholyotha, Arthit Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand Author Sutcharit, Chirasak Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand Author Lin, Aung Fauna and Flora International, Sanchaung Township, Yangon, Myanmar Author Panha, Somsak Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand & Academy of Science, The Royal Society of Thailand, Bangkok, Thailand somsak.pan@chula.ac.th text ZooKeys 2022 2022-07-04 1110 1 37 http://dx.doi.org/10.3897/zookeys.1110.82461 journal article http://dx.doi.org/10.3897/zookeys.1110.82461 1313-2970-1110-1 01302157EE404B9999DD3EC3377D929C 88D66028C7A752528DD9138A2105F895 Burmochlamys albida Pholyotha & Panha sp. nov. Figs 1 , 2C , 5D , 7A, B , 8G-I , 9C , 11C Material examined. Type material. Holotype : CUMZ 14211 (Fig. 7A ; width 4.5 mm , height 3.7 mm ). Paratypes : Same locality as holotype: CUMZ 14212 (Fig. 7B ; width 4.4 mm , height 3.2 mm ), NHMUK (two shells). Figure 7. Shells of Burmochlamys species A, B B. albida sp. nov. A holotype CUMZ 14211, and D paratype CUMZ 14212 C, D B. fasciola sp. nov. C holotype CUMZ 14213 D paratype CUMZ 14214 E, F B. moulmeinica sp. nov. E holotype CUMZ 14216 F paratype CUMZ 14217. Type locality. Limestone outcrop at Waiponla Monastery, Hpa-An, Kayin State, Myanmar ( 16°56'07.4"N , 97°42'56.8"E ). Diagnosis. Shell globose and milky-white with a yellow tinge, rarely with a faintly yellowish brown peripheral band. Animal pale fleshy grey with brown or yellow tinge and five mantle extensions. Genitalia with rather short epiphallic caecum attached by a very large and thick penial retractor muscle and rather short vagina. Description. Shell (Figs 7A, B , 8G-I ). Shell globose, small (width up to 4.5 mm, height up to 3.7 mm), thin, semi-translucent. Colour milky-white with a yellow tinge and without or rarely with faintly yellowish brown band above periphery. Protoconch and teleoconch surface with similar sculpture. Surface of body whorl with little distinct spiral furrows at regular intervals, crossed by very faintly undulating radial lines (Fig. 8G-I ). Whorls 6- 61/2 , increasing regularly; suture shallowly impressed; spire much elevated; last whorl well-rounded. Aperture obliquely crescent-shaped; peristome simple. Columellar margin simple, slightly reflected near umbilicus. Umbilicus open, narrow, and deep. Genital organs (Fig. 9C ). Atrium (at) rather short. Penis (p) moderate, cylindrical, and with penial sheath covering more than half of its length. Epiphallus (e1+e2) ca. three-sevenths of penis length; e1 cylindrical and small diameter smaller than penis and e2; e2 bulbous and ca. half of e1 length. Epiphallic caecum (ec) rather short, cylindrical, and with very large and thick penial retractor muscle (prm) attached at tip. Vas deferens (vd) thin tube. Dart apparatus large, long cylindrical, and located on atrium close to genital orifice. Vagina (v) rather short, cylindrical-shaped. Gametolytic sac (gs) bulbous; gametolytic duct (gd) cylindrical, moderate, ca. half of penis length. Free oviduct (fo) ca. one-quarter of penis length, cylindrical, and encircled with thick tissue near vagina. Radula (Fig. 11C ). Generally resembles B. cassidula . Teeth arranged in wide U-shaped rows, each row consisting of ~ 55 teeth. Central tooth monocuspid, large, and ovate spatulate shape; with two smaller triangular-shaped teeth. Laterals and marginals not differentiated, monocuspid, large spatulate shape and then gradually become narrower, elongate, rather more pointed cusp, and with one smaller triangular-shaped tooth. Some outermost teeth with a small, pointed cusp at the inner side. External appearance (Fig. 5D ). Living animal with reticulated skin, pale freshy-grey with a brown or yellow tinge. Five well-developed mantle extensions, with similar colour to body. Sole divided into three parts longitudinally; caudal foss and caudal horn well developed, similar colour to body. Etymology. The specific epithet albida is from the Latin word albidus meaning white. It refers to the whitish shell, which characterises this species. Distribution. Burmochlamys albida sp. nov. is endemic to a limestone outcrop at Waiponla Monastery. The surrounding paddy fields usually become flooded during the monsoon season (Figs 1 , 2C ). In addition, this new species is also sympatric with the limestone karst-restricted species, Sophina salweenica Sutcharit & Panha, 2020. Remarks. Among the whitish-shelled species (see Table 2 ), B. albida sp. nov. has a very indistinctly narrow yellowish brown peripheral band, whereas B. cassidula has a wide yellowish brown peripheral band, B. fasciola sp. nov. has a narrow yellowish brown peripheral band, and B. versicolor sp. nov. has yellowish brown body whorl near the aperture and wider umbilicus than the other preceding species. Anatomically, B. albida sp. nov. has a large and thick penial retractor muscle, rather slender vagina, and simple at the tip of dart apparatus. In comparison, B. cassidula has a thin penial retractor muscle, large and short vagina, and soft at the tip of dart apparatus, while B. fasciola sp. nov. has a thin penial retractor muscle, very short vagina, and solid at the tip of dart apparatus. In addition, B. versicolor sp. nov. has a thin penial retractor muscle, rather slender vagina, and relatively smaller dart apparatus with soft at the tip. Burmochlamys albida sp. nov. differs from the remaining Burmochlamys species by having a milky-white shell. While most other species have a pale to dark brownish shell without a peripheral band (see Table 2 ). Regardless of the shell colour and genitalia, this new species differs from B. cauisa and B. perpaula by spire, body whorl, and aperture. In comparison, B. cauisa has slightly elevated spire, well-rounded last whorl, and rather broad crescent-shaped aperture, while B. perpaula has slightly elevated spire, rather more convex body whorl, and narrower crescent-shaped aperture.