Hesperopetes

from Wikipedia, the free encyclopedia
Hesperopetes
Temporal occurrence
late Eocene ( Chandronian ) to late Oligocene (early Arikareeum )
37.2 to 20.43 million years
Locations
Systematics
Rodents (Rodentia)
Squirrel relatives (Sciuromorpha)
Squirrel (Sciuridae)
incertae sedis
incertae sedis
Hesperopetes
Scientific name
Hesperopetes
Emry & Korth , 2007
species

Hesperopetes is a fossil genus of squirrels (Sciuridae) from the late Paleogene . Some of the oldest known species of squirrel belong to it. The genus was scientifically described in 2007 using the teeth of three species.

features

The tooth characteristics of Hesperopetes largely correspond to those of the genus Oligopetes , which is documented from the early Oligocene in Europe, but differ in the enamel of the premolars and molars found . According to the first description, these were small croissants with strongly fluted enamel and specific molar features. The fossils differ from the genus Oligopetes in having an isolated mesostyle on the upper molar and a closed trigonid, a deep protrusion of the chewing surface that engages in one of the main cusps of the upper molars when the bite is closed, on molars m1 and m2. The teeth are also similar to those of Lophiparamys , but differ from them in the proportions of the lower molars.

Fossil History and Taxonomy

The genus Hesperopetes was described in 2007 on the basis of some teeth of the type species Hesperopetes thoringtoni and those of the two closely related species Hesperopetes jamesi and Hesperopetes blacki , the first scientific description of which was given together with the genus by the American paleontologists Robert J. Emry and William W. Korth . The fossils of the three species come from two sites that are dated differently. Hesperopetes thoringtoni is native to the White River Formation in central Wyoming from the early Chandronian in the late Eocene . Hesperopetes blacki and Hesperopetes jamesi come from the Blue Ash local fauna in South Dakota and are dated to the earliest Arikareeum in the late Oligocene . In 2017, Korth reported another finding of an indeterminate species of the genus from Orellan in the early Oligocene in Nebraska .

Hesperopetes thoringtoni is the oldest known fossil Hörnchenart that has been found so far and is probably the oldest known representative of the result of the dental features lineage of the flying squirrel . A specific classification of the species in the phylogeny , however, the squirrel is not possible.

supporting documents

  1. ↑ a b c d e R. J. Emry, WW Korth: A new genus of squirrel (Rodentia, Sciuridae) from the mid-Cenozoic of North America. Journal of Vertebrate Paleontology 27 (3), 2007; Pp. 693-698. doi : 10.1671 / 0272-4634 (2007) 27 [693: ANGOSR] 2.0.CO; 2
  2. ^ William W. Korth: First record of Hesperopetes Emry and Korth, 2007 (Rodentia, Sciuridae), from the Orellan (early Oligocene). Journal of Vertebrate Paleontology 37, June 2017. doi : 10.1080 / 02724634.2017.1318890

literature