Henricosborniidae

Henricosborniidae is a family of extinct notoungulate mammals known from the Late Paleocene to Early Miocene of Argentina, Bolivia and Brazil.[1] The name honors U.S. paleontologist Henry Fairfield Osborn.

Henricosborniidae
Temporal range: Late Paleocene-Early Miocene (Itaboraian-Deseadan)
~58.7–21 Ma
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Mammalia
Order:
†Notoungulata
Suborder:
†Notioprogonia
Family:
†Henricosborniidae

Ameghino 1901, p. 357
Genera[1]
Synonyms

Description

Henricosborniidae is a group of primitive notoungulates assigned to the suborder Notioprogonia together with Notostylopidae, not because these two families share any derived features, but because they do not clearly belong to any other clade. The henricosborniids are only known from the late Paleocene and early Eocene (Itaboraian-Casamayoran SALMA, 59 to 48 million years ago), making them slightly older and more primitive than the notostylopids. The henricosborniid dentition is the most generalized and primitive of all notoungulates, and they are believed to be near the source of all notoungulates. They have low teeth crowns and the dental formula 3.1.4.33.1.4.3.[2]

George Gaylord Simpson noted that many of the mammals that Ameghino had, and Simpson himself did, describe from the Río Chico Formation, on the Atlantic coast of Patagonia, are very difficult to distinguish from each other, both on genus and family levels. Often these mammalian groups, including the henricosborniids, are only known from one or a few isolated teeth found only at a single location. Each one of these teeth most likely represents a separate species but these species can not be properly described unless some comparable material is found.[3][4] McKenna & Bell 1997 synonymized ("= or including") many of the species named by Ameghino and others. Among other things, McKenna & Bell included Postpithecus in Othneilmarshia.[5]

Simpsonotus, with two species found in the Mealla Formation in the Jujuy Province in northwestern Argentina, are the most complete henricosborniids found. Based on features in their auditory region, they might be the most primitive notoungulates discovered. On the other hand, if these primitive features are shared by the other members of the family, Pascual, Vucetich & Fernández 1978 argued that the family should perhaps be recognized as a distinct suborder.[6]

gollark: There are probably other holes.
gollark: But the unsafe bits were *removed*, instead of safe bits being *added*, so eventually `openTab` got added and it didn't get updated and so you can now execute stuff out of the sandbox on advanced computers.
gollark: Specifically, for some foolish reason they allowed webpages to access `shell`, without unsafe functions like `run`.
gollark: Sorry, blacklisting instead of whitelisting.
gollark: Unfortunately they used whitelisting instead of blacklisting in some bits so eventually after CC updates a few functions crept through which can allow arbitrary code execution out of the sandbox.

References
  1. "Henricosborniidae". Fossilworks. Retrieved January 2014. Check date values in: |accessdate= (help)
  2. Rose 2006, Notioprogonia, p. 229
  3. Simpson 1935a, pp. 11–13
  4. Simpson 1935b, p. 13
  5. McKenna & Bell 1997, p. 456
  6. Pascual, Vucetich & Fernández 1978, Abstract

Bibliography
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