Mesoeucrocodylia

Mesoeucrocodylia is the clade that includes Eusuchia and the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day.

It was long known that Mesosuchia was an evolutionary grade, a hypothesis confirmed by the phylogenetic analysis of Benton and Clark, 1988 which demonstrated that Eusuchia (which includes all living crocodylian species) was nested within Mesosuchia. As the authors did not accept paraphyletic groups, Mesoeucrocodylia was erected to replace Mesosuchia.

Several anatomical characteristics differentiate Mesoeucrocodylia from the other crocodylomorph clades. The frontal bones of the skull are fused together into a single compound element, for example. Mesoeucrocodylians possess something of a secondary palate, formed by the posterior extension of sutured palatine bones. The otic aperture of the members of this clade is blocked posteriorly by the squamosal bone.