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An unusual early primate from the Paleocene Paskapoo Formation, Alberta, Canada

100%

Fox R.

Acta Palaeontologica Polonica

2011

tom 56

nr 1

A new plesiadapiform primate, Phoxomylus puncticuspis gen. et sp. nov., is described based on an isolated but well−preserved upper molar from the early Tiffanian (late Paleocene) Cochrane 2 locality, southwestern Alberta, Canada. Although possessing a robust postprotoconal fold, an unambiguous synapomorphy of primates, Phoxomylus differs from other plesiadapiforms in its retention of primitive molar features, including acutely pointed major cusps and sharp crests, deep trigon basin, and lack of the bunodont coronal specializations that purportedly marked the transition from insectivorous non−primate ancestors to omnivorous/frugivorous basal primates. Coronal features of the holotype of P. puncticuspis imply that during mastication the mandible was adducted in a near−vertical plane, with little capacity for the transverse movement that is already seen in molar morphology of the earliest and most basal plesiadapiform, Purgatorius. Instead, molar morphology in P. puncticuspis implies emphasis on vertical piercing and shearing, specializations for insectivory unlikely to have been derived via reversal from plesiadapiform ancestors having more bunodont molars adapted for omnivory/frugivory. If that is the case, a long “ghost lineage” must link P. puncticuspis to other, basal plesiadapiforms that have yet to be discovered but that had not yet evolved omnivorous adaptations of the dentition.

New earliest Tiffanian [Late Paleocene] mammals from Cochrane 2, Southwestern Alberta, Canada

88%

Scott C. S., Fox R. C., Youzwyshyn G. P.

Acta Palaeontologica Polonica

2002

tom 47

nr 4

New mammalian fossils at Cochrane 2, Paskapoo Formation, Alberta, Canada, document five new species and two new combinations: Ptilodus gnomus sp.nov.and Baiotomeus russelli sp.nov.(Multituberculata), Thryptacodon orthogonius comb.nov.and Litomylus grandaletes sp.nov.(“Condylarthra”), Pararyctes rutherfordi sp.nov., Bessoecetor septentrionalis comb.nov., and Paleotomus junior sp.nov.(Eutheria incertae sedis).These new taxa supplement a taxonomically diverse Cochrane 2 local fauna, representing one of the most species rich Paleocene mammalian localities in the world. An earliest Tiffanian age is estimated for the locality based on the presence of the index taxa Plesiadapis praecursor, Nannodectes intermedius, and Ectocion collinus.The Cochrane 2 local fauna fails to demonstrate a decrease in species number relative to those of late Torrejonian localities from the United States, as would be predicted by current paleoclimate scenarios; the rarity of earliest Tiffanian localities in North America suggests sampling error as a partial explanation for the apparent incongruity.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

1 Fox R.

1 Fox R. C.

1 Scott C. S.

1 Youzwyshyn G. P.

1 2011

1 2002

Wyniki wyszukiwania

An unusual early primate from the Paleocene Paskapoo Formation, Alberta, Canada

New earliest Tiffanian [Late Paleocene] mammals from Cochrane 2, Southwestern Alberta, Canada