Baikal gastropods described by W.A. Lindholm

The molluscan fauna of Lake Baikal is currently known to comprise about 150 species of gastropods, of which approximately 70% are endemics. Baikal gastropods include 8 families: Baicaliidae, Benedictiidae, Bithyniidae (Caenogastropoda), Valvatidae (Heterobranchia), Acroloxidae, Planorbidae, Lymnaeidae and Physidae (Panpulmonata). By studying the samples collected during a three-year expedition supervised by A.A. Korotneff, professor of the Kiev University, W.A. Lindholm described 55 new species, varieties (= subspecies) and forms (= morphs) that belonged to all families of gastropods (except Physidae) living in Baikal and in the connected shallow water bodies (sors). Lindholm was the first to note a wide spectrum of conchological variability of Baikal gastropods and their heterogeneous geographic distribution in the lake. Using collection of naturalist Petr Mikhno, Lindholm described two new species from Lake Hövsgöl (= Khubsugul) in Mongolia that has the hydrological connection to Lake Baikal via the Selenga River. Despite more than a century of studying the gastropod fauna in lakes Baikal and Hövsgöl, some species and subspecies described by Lindholm are rare, with only a few specimens subsequently being reported, and some have never been found again. The present study is a brief review of 46 species, subspecies and morphs of gastropods described by Lindholm. The review includes photographs of type specimens, main synonyms and references, detailed information on the type localities, diagnoses, and information on distribution in Baikal including depth zones and substrate types. All type specimens (except those of one species) are well preserved and are currently stored in the collection of the Zoological Institute of the Russian Academy of Sciences (St. Petersburg).