First record of Microstomum lineare (Plathelminthes: Dolichomicrostomida: Microstomidae) from Lake Baikal

Specimens of the widespread microturbellarian species Microstomum lineare (Müller, 1773) were collected in the coastal zone of Chivyrkuy Bay in the northern basin of Lake Baikal at a depth of 11 m. All taxonomically significant characters of the collected specimens are fully consistent with the diagnosis of this species. This is the first reliable record of the species from Lake Baikal and from Eastern Siberia, expanding the data on the range of M. lineare and increasing the list of Baikal microstomids to two species. And furthermore, the finding of M. lineare in the lake is another example of overcoming the barrier between the Baikal and Palaearctic faunas.