Answers are grounded in this paper and cite their sources.
Eutherian mammals from the Upper Cretaceous Oldman Formation, Alberta, are described. These include the leptictid proteutherian Gypsonictops lewisi Sahni, which has five lower premolars and was probably the direct lineal ancestor of G. hypoconus Simpson of Lancian age; a new genus and species of primitive and generalized erinaceoid insectivore, which is the most adequate dental ancestor known for all Lipotyphla, Tupaiidae, Primates, Dermoptera, Chiroptera, and all of the ungulate mammals; and the first pre-Lancian occurrence in North America of the Family Palaeoryctidae.
No takes yet. Share an insight, caveat, or question.
Richard C. Fox (1979) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: