A Possible Pterosaur Wing Phalanx from the Kaiparowits Formation (Late Campanian) of Southern Utah, USA


  • Andrew A Farke Raymond M. Alf Museum of Paleontology, 1175 West Baseline Road, Claremont, CA 91711
  • Chiara A Wilridge The Webb Schools, 1175 West Baseline Road, Claremont


Pterosauria, Kaiparowits Formation, Cretaceous


An isolated bone from the late Campanian-aged Kaiparowits Formation of southern Utah is tentatively identified as the terminal wing phalanx (manual phalanx IV-4) from a pterosaur, representing the first report of this clade from the formation. The specimen is 60 mm long and hollow, with thin and delicate walls and expanded ?proximal and ?distal ends. This is consistent with anatomy reported for equivalent elements in pterodactyloid pterosaurs. Although the specimen cannot be more precisely identified, it is consistent with occurrences of pterosaurs in penecontemporaneous terrestrial depositional environments throughout western North America.

Possible manual phalanx from a pterosaur, RAM 15445. A) Cross section of bone at point indicated by line to B; B) Photograph of bone; C) interpretive line drawing of bone. Abbreviations: i, impression; s, sulcus. Upper scale bar, for A, equals 1 mm. Lower scale bar, for B and C, equals 5 cm. Figure by the authors