INVESTIGADORES
APESTEGUIA Sebastian
artículos
Título:
A highly specialized mammalian skull from the Late Cretaceous of South America
Autor/es:
GUILLERMO W. ROUGIER; SEBASTIÁN APESTEGUÍA; LEANDRO GAETANO
Revista:
NATURE
Editorial:
NATURE PUBLISHING GROUP
Referencias:
Lugar: Londres; Año: 2011 p. 98 - 102
ISSN:
0028-0836
Resumen:
Dryolestoids are an extinct mammalian group belonging to the
lineage leading to modern marsupials and placentals. Dryolestoids
are known by teeth and jaws from the Jurassic period of North
America and Europe, but they thrived in South America up to the
end of the Mesozoic era and survived to the beginnings of the
Cenozoic. Isolated teeth and jaws from the latest Cretaceous of
South America provide mounting evidence that, at least in western
Gondwana, dryolestoids developed into strongly endemic groups by
the Late Cretaceous. However, the lack of pre-Late Cretaceous
dryolestoid remainsmade study of their origin and early diversification
intractable. Here we describe the first mammalian remains
from the early Late Cretaceous of South America, including two
partial skulls and jaws of a derived dryolestoid showing dental
and cranial features unknown among any other group of
Mesozoic mammals, such as single-rooted molars preceded by
double-rooted premolars, combined with a very long muzzle,
exceedingly long canines and evidence of highly specialized
masticatory musculature. On one hand, the new mammal shares
derived features of dryolestoids with forms from the Jurassic of
Laurasia, whereas on the other hand, it is very specialized and
highlights the endemic, diverse dryolestoid fauna from the
Cretaceous of South America. Our specimens include only the
second mammalian skull known for the Cretaceous of Gondwana,
bridging a previous 60-million-year gap in the fossil record, and
document the whole cranial morphology of a dryolestoid, revealing
an unsuspected morphological and ecological diversity for nontribosphenic
mammals.