User:Shellnut/Bronze sandbox

Many systems have been developed for the classification of bivalves, but for the past two centuries no professional consensus has existed on bivalve phylogeny. In the earlier taxonomic systems experts used only one characteristic feature for their taxonomic system, either shell morphology, hinge type, or the type of gills. Many conflicts existed due to taxonomies based on single organ systems and conflicting naming schemes proliferated. One of the most widely accepted systems was that of Newell in the Treatise on Invertebrate Paleontology Moore [ed.] (1969), which employed a classification system based on general shell shape, microstructures and hinge configuration.^[1] Since features such as hinge morphology, dentition, mineralogy, and shell morphology and composition change slowly these characteristics can be used for defining major taxonomic groups. Due to the numerous fossil lineages, DNA sequence data is of limited use in classifying extinct species.

In the last decade, taxonomic studies using cladistical analyses of multiple organ systems, shell morphology (including species in the fossil record), and modern molecular phylogenetics have drawn what experts believe to be a more accurate phylogeny of the Bivalvia.^{[2][3][4][5][6]} Based upon these studies a new proposed classification system for the Bivalvia was published in 2010 by Bieler, Carter & Coan.^[7] Currently, in 2012, this new taxonomic classification system has been recognized by the World Register of Marine Species (WoRMS) as the classification system for the Bivalvia. Some experts still maintain that the Anomalodesmacea is a separate Subclass, whereas Bieler, et al. place it as the Order Anomalodesmata within the Heterodonta. Molecular phylogeny work continues, further refining the taxonomy of the Bivalvia.^[8][9]

In May 2010 a new taxonomy of the Bivalvia was published in the journal Malacologia. In this classification 324 families were recognized as valid, 214 of which are known exclusively as fossils and 110 families occur in the Recent with or without a fossil record.^[10] This publication consisted of two parts :

• Nomenclator of Bivalve Names of the Family-Group and above
• Classification of Bivalve Families (under the redaction of Rüdiger Bieler, Joseph G. Carter and Eugene V. Coan)

The 2010 proposed taxonomy of the Class Bivalvia is as follows:

Class: Bivalvia