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Anguispira holroydensis
Anguispira holroydensis was a species of pulmonate land snail in the family Discidae, the disk snails. The species is only known from fossilized specimens. It was first described by Loris S. Russell in 1956.[1] FossilsThe most well-studied A. holroydensis fossil was found in the North Park Formation in Carbon County, Wyoming. The shell's position in the formation dates it to the Late Miocene.[1] Physical appearanceRussell describes the A. holroydensis fossil as being visually similar to Anguispira cumberlandiana and Anguispira alternata. The shell is small, only 7.9 mm in diameter, with a low spire and deep umbilicus. The surface of the first one and a half whorls is smooth, with the remainder being marked by fine retractive ridges (costulae).[1] References
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