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 Author Man, Nem Sian 0000-0002-4453-734X Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand & Department of Zoology, University of Yangon, University Avenue Road, Kamayut Township 11041, Yangon, Myanmar Author Ablett, Jonathan D. 0000-0002-7277-1934 Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW 7 5 BD, UK Author Lwin, Ngwe 0000-0002-4394-3741 Fauna and Flora International, No. 35, 3 rd Floor, Shan Gone Condo, Myay Ni Gone Market Street, Sanchaung Township, Yangon, Myanmar Author Sutcharit, Chirasak 0000-0001-7670-9540 Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand Author Panha, Somsak 0000-0002-4431-2458 Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand & Academy of Science, The Royal Society of Thailand, Bangkok 10300, Thailand text ZooKeys 2024 2024-07-30 1208 173 239 journal article 10.3897/zookeys.1208.116083 0215503D-E8B4-4179-89F6-FB2CCC59F37E Genus Opeas Albers, 1850 Bulimus ( Opeas ) Albers, 1850: 175 , 176. Stenogyra ( Opeas ) — von Martens 1860: 265 , 266. Opeas — Fischer and Crosse 1877: 592 . Pilsbry 1906: 122 . Gude 1914: 354 . Zilch 1959: 351 , 352. van Benthem Jutting 1952: 378 . Schileyko 1999: 492 . Type species. Helix goodallii Miller, 1822 [junior homonym of Férussac (1821) ] accepted as Opeas hannense ( Rang, 1831 ) , subsequent designation by von Martens in Albers (1860: 265) . Diagnosis. Shell small, slender, and conical; spire high, turreted, cylindrically, and gradually attenuated; embryonic whorls smooth; subsequent whorls with fine radial striations or growth lines. Aperture vertical, narrow, oblong, columellar margin expanded, and columella straight or concave. Umbilicus narrowly opened or closed. Penis cylindrical tube with short epiphallus, and flagellum and penial sheath absent; vagina long ~ 1 / 2 of penis length. Remarks. Opeas and Tortaxis Pilsbry, 1906 generally resemble one another in having slender conical or cylindrical shells, nearly smooth to fine striations, and flatly convex whorls (Table 2 ). However, Opeas has a smaller size, straight columella, and mostly oblong aperture, whereas Tortaxis displays mostly larger size, nearly straight or slightly concave columella with a spiral fold, and more or less obliqued aperture. Likewise, Opeas is distinctly differentiated from Bacillum in that it is smaller in size, has a straight columella, fine shell sculptures and embryonic whorls which are narrowly rounded. In contrast, Bacillum exhibits a larger shell size, truncated and concave columella, stronger shell sculptures, and the embryonic whorls cylindrically rounded. This genus is distributed in tropical and subtropical regions in Europe, Asia, Africa, and North America, and comprises nearly 200 species ( Schileyko 1999 ; MolluscaBase 2023 ). In Myanmar , two species are recorded ( Gude 1914 ).