 In May 2010 , a new taxonomy of the Bivalvia was published in the journal Malacologia . In compiling this , the authors used a variety of phylogenetic information including molecular analysis , anatomical analysis , shell morphology and shell microstructure as well as bio @-@ geographic , paleobiogeographic and stratigraphic information . In this classification 324 families are recognized as valid , 214 of which are known exclusively from fossils and 110 of which occur in the recent past , with or without a fossil record . This classification has since been adopted by WoRMS . 
