Journal of Mammalian Evolution

, Volume 18, Issue 3, pp 153–161

Protungulatum, Confirmed Cretaceous Occurrence of an Otherwise Paleocene Eutherian (Placental?) Mammal


    • Department of BiologySan Diego State University
  • Yue Zhang
    • Department of BiologySan Diego State University
    • Department of Evolution, Ecology and Organismal BiologyOhio State University
  • Tony Harper
    • Department of BiologySan Diego State University
  • Richard L. Cifelli
    • Oklahoma Museum of Natural HistoryUniversity of Oklahoma
Original Paper

DOI: 10.1007/s10914-011-9162-1

Cite this article as:
Archibald, J.D., Zhang, Y., Harper, T. et al. J Mammal Evol (2011) 18: 153. doi:10.1007/s10914-011-9162-1


Neither pre-Cenozoic crown eutherian mammals (placentals) nor archaic ungulates (“condylarths”) are known with certainty based on the fossil record. Herein we report a new species of the Paleocene archaic ungulate (“condylarth”) Protungulatum from undisputed Late Cretaceous aged rocks in Montana USA based on an isolated last upper premolar, indicating rare representatives of these common early Tertiary mammals appeared in North America a minimum of 300 k  years before the extinction of non-avian dinosaurs. The other 1200 mammal specimens from the locality are characteristic Late Cretaceous taxa. This discovery overturns the current hypothesis that archaic ungulates did not appear in North America until after the Cretaceous/Tertiary (K/T) boundary and also suggests that other reports of North American Late Cretaceous archaic ungulates may be correct. Recent studies, including ours, cannot determine whether Protungulatum does or does not belong to the crown clade Placentalia.


EutheriaPlacentaliaArchaic ungulateProtungulatumLate CretaceousHell Creek Formation

Copyright information

© Springer Science+Business Media, LLC 2011