A new astrapothere (Mammalia, Meridiungulata) from La Meseta Formation, Seymour (Marambio) Island, and a reassessment of previous records of Antarctic astrapotheres

Title Variants

Alternative: New Antarctic astrapothere

Related Titles

Series: American Museum novitates, no. 3718

By

Bond, Mariano.
Kramarz, Alejandro.
MacPhee, R. D. E.
Reguero, Marcelo.

Type

Book

Material

Published material

Publication info

[New York], American Museum of Natural History, c2011

Notes

Caption title.

"June 1, 2011."

During the past quarter century, the uplifted nearshore sediments comprising the Eocene La Meseta Formation (LMF) of Seymour (Marambio) Island have produced a diverse assemblage of terrestrial mammals that closely, but not exactly, resembles late Early Eocene faunas from southern Patagonia. This assemblage includes the only astrapothere and litoptern fossils known from outside South America. The occurrence of astrapotheres in LMF was originally indicated by fragmentary dental remains tentatively referred to family Trigonostylopidae on the basis of their general resemblance to the Patagonian genus Trigonostylops Ameghino. In this contribution we describe a new astrapothere specimen from LMF; unlike specimens collected previously, this one is a complete and excellently preserved lower cheek tooth, providing a basis for a review of all previous records of Astrapotheria from this formation. This tooth (probably p4 rather than m1) is sufficiently distinct from all other known astrapothere cheek teeth to warrant assignment to a new genus and species, Antarctodon sobrali. It has a transversally elongated entoconid, resembling that observed in at least one specimen of the Mustersan genus Astraponotus, but the tooth as a whole is much lower crowned and less lophodont than in the latter. Phylogenetic analysis suggests that Antarctodon is closer to genera classified by previous authors as astrapotheriids (e.g., Albertogaudrya and Tetragonostylops) than it is to Trigonostylops. Reexamination of other LMF specimens previously referred to Trigonostylopidae reveals that some specimens are attributable to this new taxon and others either are not astrapotheres at all or lack distinctive features. Consequently, at present the record of order Astrapotheria in Antarctica should be considered as restricted to non-trigonostylopids.

Subjects

Antarctica , Antarctodon , Antarctodon sobrali , Astrapotheria , Eocene , La Meseta Formation , La Meseta Formation (Antarctica) , Mammals, Fossil , Paleontology , Seymour Island , Teeth, Fossil

Call Number

QL1 .A436 no.3718 2011

Language

English

Identifiers

OCLC: 728156717