PALAEOHETERODONTA is a subclass of bivalve molluscs . It contains the extant orders Unionoida (freshwater mussels) and Trigonioida . They are distinguished by having the two halves of the shell be of equal size and shape, but by having the hinge teeth be in a single row, rather than separated into two groups, as they are in the clams and cockles .
* 1 2010 Taxonomy of the
* 2 References
2010 TAXONOMY OF THE PALAEOHETERODONTA
In 2010 a new proposed classification system for the Bivalvia was published in by Bieler, Carter & Coan revising the classification of the Bivalvia, including the subclass Paleoheterodonta. Superfamilies and families as listed by Bieler et al. Use of † indicate families and superfamilies that are extinct.
* †Beichuanioidea Liu & Gu, 1988
* †Beichuaniidae Liu & Gu, 1988
* †Megatrigonioidea Van Hoepen, 1929
* † Megatrigoniidae Van Hoepen, 1929 * †Iotrigoniidae Savelive, 1958 * †Rutitrigoniidae Van Hoepen, 1929
* †Myophorelloidea Kobayashi, 1954
* †Myophorellidae Kobayashi, 1954 * †Buchotrigoniidae Leanza, 1993