 Today, knowledge is sufficient to divide the family into five Subfamilies (see below), which together contain more than sixteen genera, the most abundant being "Trigonia", "Myophorella", "Laevitrigonia", and "Orthotrigonia".Members of the Trigoniidae are identified by the large and complex dentition that joins the two valves together and allows articulation.The teeth and supporting area can take up almost a third of the volume of the shell.