Gyraulus is a genus of small, mostly air-breathing, freshwater snails, aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails.
The genus Gyraulus is known from the Early Cretaceous to the present. Fossils attributed to Gyraulus sp. have been found in the lakebottom sediments of the Yixian Formation in China, dating to 125 million years ago.
The minute species Gyraulus crista, although technically a pulmonate gastropod, does not use air for respiration, but instead has a mantle cavity which has much water.
Gyraulus crista
Distribution
The distribution of this genus is Holarctic.
Habitat
These snail snails live on water plants in freshwater.
Shell description
Shell of the species within this genus are small, and are mostly almost planispiral in their coiling.
