The Pen Formation is a
Campanian-age geologic unit in the western United States.
Vertebrate fauna
Sharks are well known from the Pen Formation.
* ''
Lonchidion selachos''
* ''
Squalicorax kaupi''
* ''
Cretorectolobus olsoni''
* ''
Ischyrhiza mira''
* ''
Scapanorhynchus texanus''
* ''
S. raphiodon''
* ''
Cretolamna appendiculata''
Other fishes include ''
Xiphactinus
''Xiphactinus'' (from Latin and Greek for " sword-ray") is an extinct genus of large (Shimada, Kenshu, and Michael J. Everhart. "Shark-bitten Xiphactinus audax (Teleostei: Ichthyodectiformes) from the Niobrara Chalk (Upper Cretaceous) of Kansas. ...
'',
the ray ''
Ptychotrygon
''Ptychotrygon'' is a genus of sawfish-like Late Cretaceous ray whose fossils have been found worldwide. It, '' Ptychotrygonoides'', '' Texatrygon'', and '' Asflapristis'' are members of the family Ptychotrygonidae within the suborder Sclerorhyn ...
'',
and
gar
Gars are members of the family Lepisosteidae, which are the only surviving members of the Ginglymodi, an ancient holosteian group of ray-finned fish, which first appeared during the Triassic, over 240 million years ago. Gars comprise seven livin ...
.
The nodosaurid ankylosaurs ''
Acantholipan
''Acantholipan'' is a genus of herbivorous nodosaurid dinosaur from Mexico from the early Santonian age of the Late Cretaceous. It includes one species, ''Acantholipan gonzalezi.''
Discovery and naming
In the north of Mexico, fragmentary fossil ...
'' and CPC 273 have also been found in the Pen Formation.
[Héctor E. Rivera-Sylva; Eberhard Frey; Wolfgang Stinnesbeck; Gerardo Carbot-Chanona; Iván E. Sanchez-Uribe; José Rubén Guzmán-Gutiérrez (2018). "Paleodiversity of Late Cretaceous Ankylosauria from Mexico and their phylogenetic significance". Swiss Journal of Palaeontology. in press. .]
Footnotes
{{Reflist, 3, refs=
["Big Bend National Park," Hunt, Santucci, and Kenworthy (2006); page 65.]
References
* Hunt, ReBecca K., Vincent L. Santucci and Jason Kenworthy. 2006. "A preliminary inventory of fossil fish from National Park Service units." in S.G. Lucas, J.A. Spielmann, P.M. Hester, J.P. Kenworthy, and V.L. Santucci (ed.s), Fossils from Federal Lands. New Mexico Museum of Natural History and Science Bulletin 34, pp. 63–69.
Cretaceous geology of Texas