Santonian genus first appearances

Platecarpus ("oar wrist") is an extinct genus of aquatic lizards belonging to the mosasaur family, living around 84–81 million years ago during the middle Santonian to early Campanian, of the Late Cretaceous period. Fossils have been found in the United States and possibly in Belgium, Australia, and Africa. A well-preserved specimen of Platecarpus shows that it fed on moderate-sized fish, and it has been hypothesized to have fed on squid and ammonites as well. Like other mosasaurs, it was initially thought to have swum in an eel-like fashion, although another study suggests that it swam more l

Eonatator is an extinct genus of marine lizard belonging to the mosasaur family. It is a close relative of Halisaurus, and part of the same subfamily, the Halisaurinae. It is known from the Late Cretaceous of North America, Colombia and Sweden. Originally, this taxon was included within Halisaurus, but was placed in its own genus, which also led to the subfamily Halisaurinae being created for the two genera.

Meniscoessus is a genus of extinct multituberculates from the Upper Cretaceous Period that lived in North America.

Ectenosaurus is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Plioplatecarpinae subfamily alongside genera like Angolasaurus and Platecarpus. Ectenosaurus is known from the Santonian and Campanian of Kansas, Alabama, and Texas.

Spatangus is a genus of heart urchins in the Spatangidae family. The genus is synonymous with the previously recognised genera Prospatangus Lambert, 1902 and Spatagus. There are nine recognised species. The type species is Spatangus purpureus Müller, 1776 by subsequent designation (Rowe & Gates, 1995).

Cimolomys (Greek for "chalk mouse") is a mammal genus from the Upper Cretaceous of North America. It was a member of the extinct order Multituberculata within the suborder Cimolodonta and family Cimolomyidae.

Palmoxylon, also called petrified palmwood, is an extinct genus of palm named from petrified wood found around the world.

Saurodon (from , 'lizard' and 'tooth') is an extinct genus of ichthyodectiform ray-finned fish from the Late Cretaceous.