Undetermined undetermined

Hsu, Chia-Hsin, Osipova, Diana & Lin, Chien-Hsiang, 2025, Fossil freshwater mollusks from the Early Pleistocene (Calabrian) of northern Taiwan, Geodiversitas 47 (20), pp. 721-737 : 729

Lymnaeidae gen. et sp. indet.

( Fig. 7A)

MATERIAL EXAMINED. — Taiwan • 2 specimens; Shuiniukeng (= Water Buffalo Valley ), New Taipei City; Tananwan Formation, Early Pleistocene, Calabrian ; ASIZF0100921 , ASIZF0100942 .

DESCRIPTION

Shell small (up to 1.5 cm), oval and elongated, dextral. Exposed whorls slightly slopping, with long body whorl. Based on the exposed part of the spire, it appears to be short.

REMARKS

Identifying this specimen is challenging due to its partial embedding in sediments. However, the exposed whorls, including a dextral shell, a long body whorl and a shorter spire, suggest that it belongs to the family Lymnaeidae . In Taiwan, four extant species of this family have been reported, including Galba truncatula (Müller, 1774) , Orientogalba ollula (Gould, 1859) , Radix auricularia (Linnaeus, 1758) , and Radix plicatula ( Benson, 1842) ( Chang 1991; Chen 2011; Chung & Shao 2022). The elongated body whorl of the studied specimens with a spire still higher than in R. auricularia , thus it makes them similar in general outline to O. ollula and R. plicatula , although better-preserved specimens are needed for more precise identification.