Gyraulus
''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.Pan, H. and Zhu, X. (2007). "Early Cretaceous non-marine gastropods from the Xiazhuang Formation in North China." ''Cretaceous Research'', 28(2): 215-224. Description Shells of the species within this genus are small, and are mostly almost planispiral in their coiling. Distribution and habitat The distribution of this genus is Holarctic. These snail snails live on water plants in freshwater. Species The following species are recognised in the genus ''Gyraulus'': *'' Gyraulus acronicus'' *†'' Gyraulus aegaeus'' *†'' Gyraulus albertanus'' *'' Gyraulus albidus'' *'' Gyraulus albus'' *†'' G ...
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