A new apheliscine "condylarth" mammal from the late paleocene of Montana and Alberta and the phylogeny of "hyopsodontis"

Shawn P. Zack, Tonya A. Penkrot, David W. Krause, Mary C. Maas

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

We describe a new genus, including at least two species, of apheliscine "condylarth," Gingerichia geoteretes from Douglass and Glennie quarries in the eastern Crazy Mountains Basin, south-central Montana, and Gingerichia hystrix from Cochrane 2, in Alberta, Canada, both late Paleocene (early Tiffanian; Ti1) sites. Gingerichia geoteretes is based on a nearly complete lower cheek dentition and is distinctive among apheliscines in lacking paraconid, metaconid, and anterior cingulid on p4 and possessing lower molars with less reduced paraconids (particularly m2 and m3) and relatively elevated trigonids. Gingerichia hystrix appears to represent a slightly older species and its morphology is slightly less specialized than that of G. geoteretes. These taxa are rare elements in the Cochrane 2 and Douglass Quarry assemblages and are the earliest known apheliscines; they therefore provide a new opportunity to elucidate both the composition and the phylogenetic relationships of the Apheliscinae and other small-bodied "condylarths." Phylogenetic analysis indicates that Hyopsodus and mioclaenids form a monophyletic group that excludes other taxa. traditionally placed in Hyopsodontidae, including apheliscines. Accordingly, Hyopsodontidae is redefined to include the traditional contents of Noclaenidae. Other "hyopsodontids," including apheliscines, form a monophyletic clade, and Apheliscidae is revived to accommodate this group. Finally, we recognize Haplaletes setior as the lower dentition of Utemylus latomius or a close relative.

Original languageEnglish (US)
Pages (from-to)809-830
Number of pages22
JournalActa Palaeontologica Polonica
Volume50
Issue number4
StatePublished - Nov 1 2005
Externally publishedYes

Keywords

  • "Condylarthra"
  • Apheliscidae
  • Hyopsodontidae
  • Mammalia
  • N. America
  • Paleocene
  • Tiffanian

ASJC Scopus subject areas

  • Palaeontology

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