Chondrichthyan and osteichthyan paleofaunas from the Cretaceous (Late Maastrichtian) Fox Hills Formation of North Dakota, USA: Paleoecology, paleogeography, and extinction - BAP #398
As part of a study of the Vertebrata found in the Late Cretaceous (Early Maastrichtian to Middle Late Maastrichtian) Fox Hills Formation, 48 sites in western and central North Dakota were collected to interpret the chondrichthyan and osteichthyan paleofaunas. Based mostly on teeth, 19 shark species, 16 skate and ray species, and one ratfish species were recognized. Of those, three taxa are new.
Fox Hills fishes were derived from deep and shallow marine, brackish, and freshwater habitats. When coupled with paleogeographic distribution information, the Fox Hills fish fauna indicates that some taxa represent a recurring assemblage of species that have a “large-river delta” habitat preference, as found today on major deltas of most continents.
The Fox Hills paleofauna documents fish extinction at the close of the Cretaceous. None of the 36 chondrichthyan species and none of the 20 osteichthyan species recovered from the Fox Hills Formation are found in the Paleocene worldwide. 58% of Fox Hills chondrichthyan and 77% of osteichthyan genera, and 20% of chondrichthyan and 33% of osteichthyan families, did not survive after the Cretaceous. Support for this interpretation is provided by comparison of the Fox Hills paleofauna to the Paleocene Cannonball Formation paleofauna in North Dakota. None of the 13 Cannonball chondrichthyan species, nor any of the four Cannonball osteichthyan species, occur in the Fox Hills Formation.
John W. Hoganson, J. Mark Erickson, and F. D. Holland, Jr.
Issue: BAP 398
Year published: 2019