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A Cretaceous mammal from Tanzania

100%

Krause D. W., Gottfried M. D., O'Connor P. M., Roberts E. M.

Acta Palaeontologica Polonica

2003

tom 48

nr 3

We report here the discovery of a Cretaceous mammal from the “Red Sandstone Group” of southwestern Tanzania. This specimen is one of only a very few Cretaceous mammals known from Gondwana in general and Africa in particular. The specimen consists of a short, deep left dentary that bore a large, procumbent central incisor, and five single−rooted, hypsodont cheek−teeth. The specimen is very tentatively identified as a sudamericid, and thus may represent the first African record of an enigmatic clade of mammals, the Gondwanatheria, which is otherwise known from the Late Cretaceous and Paleogene of several other Gondwanan landmasses. Unfortunately, the precise age of the specimen could not be determined. If it is pre−Campanian and if its identity as a sudamercid is corroborated through subsequent discoveries, it represents the earliest known gondwanatherian. If the specimen is from the Campanian or Maastrichtian, and again assuming its identification is correct, it has the potential to refute a recently formulated biogeographic hypothesis predicting the absence of certain terrestrial and freshwater vertebrate taxa, including gondwanatherians, in Africa (i.e., those that evolved elsewhere on Gondwana after Africa became an isolated landmass).

First Mesozoic record of the stingray Myliobatis wurnoensis from Mali and a phylogenetic analysis of Myliobatidae incorporating dental characters

64%

Claeson K. M., O'Leary M. A., Roberts E. M., Sissoko F., Bouare M., Tapanila L., Goodwin D., Gottfried M. D.

Acta Palaeontologica Polonica

2010

tom 55

nr 4

New specimens, including the first record of lower dental plates, of the extinct myliobatid Myliobatis wurnoensis were recovered from the Maastrichtian (Late Cretaceous) of the Iullemmeden Basin, Mali, and are the oldest record of the taxon. We evaluated the phylogenetic position of this taxon with reference to other myliobatids (extinct and extant) using osteology and dentition. Our results indicate that Myliobatinae and Myliobatis are each paraphyletic, and that Aetobatus and Rhinoptera are monophyletic. We also found that taxa known only from the Cretaceous, Brachyrhizodus and Igdabatis, are highly nested within Myliobatidae. The phylogenetic position of these taxa unambiguously extends the origin of Myliobatidae and most of its representative taxa into the Mesozoic.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

2 Gottfried M. D.

2 Roberts E. M.

1 Bouare M.

1 Claeson K. M.

1 Goodwin D.

1 Krause D. W.

1 O'Connor P. M.

1 O'Leary M. A.

1 Sissoko F.

1 Tapanila L.

1 2010

1 2003

Wyniki wyszukiwania

A Cretaceous mammal from Tanzania

First Mesozoic record of the stingray Myliobatis wurnoensis from Mali and a phylogenetic analysis of Myliobatidae incorporating dental characters