... based on a partial shell (ROM 56647) from the Santonian Milk River Formation of southern Alberta, estimated at approximately 84 Ma. This represents the oldest relatively complete shell of a trionychid from North America. Plastomenidae, a pan-trionychid clade known only from the fossil record...

...Walter G. Joyce; Tyler R. Lyson Abstract Plastomenidae is a poorly diagnosed clade of extinct soft-shelled turtles (Trionychidae) known from the Campanian to Eocene of North America. Five skulls, a mandible, two carapaces, and numerous plastral remains from the Hell Creek Formation (Late Cretaceous...

... to Gilmoremys lancensis near the base of the clade Plastomenidae. Like the majority of previously described plastomenid materials, the type specimen of Gilmoremys gettyspherensis n. sp. was collected from a mudstone horizon, suggesting a preference for ponded environments. UUID: http://zoobank.org/e7165061-d86b...

... to a phylogeny. The nomenclatural system of Joyce et al. (2004) only provides names for the primary clades of extant turtles. Various authors have therefore formulated names for groups of fossil turtles (e.g., Adocusia Danilov and Parham, 2006 ; Palatochelydia Joyce and Lyson, 2010 ; Plastomenidae Joyce...