Anisus spirorbis ( Linnaeus, 1758 )

Marković, Vanja, Gojšina, Vukašin, Novaković, Boris, Božanić, Milenka, Stojanović, Katarina, Karan-Žnidaršič, Tamara & Živić, Ivana, 2021, The freshwater molluscs of Serbia: Annotated checklist with remarks on distribution and protection status, Zootaxa 5003 (1), pp. 1-64 : 29

55. Anisus spirorbis ( Linnaeus, 1758)

Findings in Serbia.

Paraspira spirorbis : Hesse (1929).

Anisus spirorbis : Karaman (2001 a).

Anisus (Spirorbis) spirorbis : Karaman (2001).

Anisus (Anisus) spirorbis : Karaman & Karaman (2007).

Morphology. Small-sized snail. (up to 6 mm diameter). Shell is flattened and translucent with 4–5 whorls. Animal is red or grey with transparent tentacles. For more details see Welter-Schultes (2012: 59, figure in the middle of the page).

Distribution and ecology. Western Palearctic species up to 1500 m.a.s.l. Inhabits small stagnant waters in lowland regions. Tolerates temporary droughts. Populations can be abundant under optimal conditions (Welter-Schultes 2012). In Serbia, its scarce findings are limited to the Danube River, and few ponds near the Danube and Tamiš Rivers.

Other remarks. The type species of the genus. Endangered in Germany and Austria, vulnerable in Switzerland. This snail can be confused with Anisus leucostoma , and sometimes it is considered as a broad-whorled morphotype of the latter species ( Glöer, 2019). On the IUCN Red List of threatened species it has been assessed as LC (Vavrova et al. 2011).