Pen Formation

Sharks are well known from the Pen Formation.^[1]

• Lonchidion selachos^[1]
• Squalicorax kaupi^[1]
• Cretorectolobus olsoni^[1]
• Ischyrhiza mira^[1]
• Scapanorhynchus texanus^[1]
• S. raphiodon^[1]
• Cretolamna appendiculata^[1]

Other fishes include Xiphactinus,^[1] the ray Ptychotrygon,^[1] and gar.^[1] The nodosaurid ankylosaurs Acantholipan and CPC 273 have also been found in the Pen Formation.^[2]

• 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.