Redescription of Prognathodon lutugini (Squamata, Mosasauridae)

Abstract

Dollosaurus lutugini (Yakovlev, 1901) is the only valid species known from the territory of the former USSR. It was described from Campanian deposits of Eastern Ukraine on the basis of an incomplete skeleton. This study provides a description of an osteological material including the previously undescribed epipterygoid and squamosal. Phylogenetic analysis of a data matrix of 37 terminal taxa and 135 characters shows that D. lutugini and Prognathodon solvayi Dollo, 1889 are sister taxa. P. lutugini is distinct from P. solvayi by possession of smooth enamel surface of teeth, depression of anteriormost trunk vertebrae condyles, larger relative length of cervical vertebrae, and a distinct, horizontally interdigitating articulating surface of the splenial and angular. We conclude that D. lutugini is in Prognathodon clade; generic name of Dollosaurus Yakovlev, 1901 is a subjective junior synonym of the Prognathodon Dollo, 1889.