[3] Similodonta is a small bivalve which was first described in 1964 by Helen Soot-Ryen in an Arkiv för Mineralogi och Geologi, Kungliga Svenska Vetenskapsakademien paper.

The triangular shape on the dorsal side is formed by the sharp angle at which the anterior and posterior hinge edges meet at the umbo.

[3] The type species for the genus, Similodonta similis, has been found in Late Ordovician, Ashgill epoch, sediments of the upper Richmond Group exposed near Spring Valley, Minnesota.

[3] Another united kingdom species, Similodonta magna was described in 1946 by Lamont and is known from Ashgillian fossils found near the Scottish coastal town of Girvan.

While similar in morphology to S. ceryx, S. magna is distinguished by the stronger curve in the posterior edge and muscle scars that are not as distinct.

[3] Dating from the Latest Ordovician, the species Similodonta wahli was described in 1991 by Isakar from fossils found in the Ärina Formation of Northern Estonia.