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A new apheliscine 'condylarth' mammal from the Late Paleocene of Montana and Alberta and the phylogeny of 'hyopsodontids'

100%

Zack S. P. , Penkrot T. A. , Krause D. W. , Maas M. C.

Acta Palaeontologica Polonica

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2005

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tom 50

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nr 4

809-830

EN

Fieldwork in the early Late Jurassic (Oxfordian) Qigu Formation of the Junggar Basin in Northwest China (Xinjiang Autonomous Region) produced teeth and mandibular fragments of a new docodont. The new taxon has a large “pseudotalonid” on the lower molars, and by retention of crest b−g exhibits closer affinities to Simpsonodon and Krusatodon from the Middle Jurassic of Europe than to the other known Asian docodonts Tashkumyrodon, Tegotherium, and Sibirotherium. It differs from the Haldanodon–Docodon−lineage by the “pseudotalonid” and large cusps b and g. A PAUP analysis based on lower molar characters produced a single most parsimonious tree with two main clades. One clade comprises Docodon, Haldanodon, and Borealestes, and the other Dsungarodon, Simpsonodon, and Krusatodon plus the Asian tegotheriids. Analysis of the molar occlusal relationships using epoxy casts mounted on a micromanipulator revealed a four−phase chewing cycle with transverse component. The molars of the new docodont exhibit a well developed grinding function besides cutting and shearing, probably indicating an omnivorous or even herbivorous diet. A grinding and crushing function is also present in the molars of Simpsonodon, Krusatodon, and the Asian tegotheriids, whereas Borealestes, Haldanodon, and Docodon retain the plesiomorphic molar pattern with mainly piercing and cutting function.

2

A Cretaceous mammal from Tanzania

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

Acta Palaeontologica Polonica

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2003

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tom 48

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nr 3

EN

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).

3

Na tropie zabójcy sprzed wieków

100%

Rogers R. R. , Krause D. W.

Świat Nauki

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2007

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nr 03

4

A new mammal from the Turonian–Campanian (Upper Cretaceous) Galula Formation, southwestern Tanzania

75%

O’Connor P. M. , Krause D. W. , Stevens N. J. , Groenke J. R. , MacPhee R. D. E. , Kalthoff D. C. , Roberts E. M.

Acta Palaeontologica Polonica

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2019

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tom 64

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nr 1

EN

We here establish a new mammaliaform genus and species, Galulatherium jenkinsi (Mammalia), from the Upper Cretaceous Galula Formation in the Rukwa Rift Basin of southwestern Tanzania. This represents the first named taxon of a mammaliaform from the entire Late Cretaceous of continental Afro-Arabia, an interval of 34 million years. Preliminary study of the holotypic and only known specimen (a partial dentary) resulted in tentative assignation to the Gondwanatheria, a poorly known, enigmatic clade of Late Cretaceous–Paleogene Gondwanan mammals (Krause et al. 2003). The application of advanced imaging (μCT) and visualization techniques permits a more detailed understanding of key anatomical features of the new taxon. It reveals that the lower dentition consisted of a large, procumbent lower incisor and four cheek teeth, all of which were evergrowing (hypselodont). Importantly, all of the teeth appear devoid of enamel. Comparisons conducted with a range of Mesozoic and selected Cenozoic mammaliaform groups document a number of features (e.g., columnar, enamel-less and evergrowing teeth, with relatively simple occlusal morphology) expressed in Galulatherium that are reminiscent of several distantly related groups, making taxonomic assignment difficult at this time. Herein we retain the provisional referral of Galulatherium (RRBP 02067) to Gondwanatheria; it is most similar to sudamericids such as Lavanify and Bharratherium from the Late Cretaceous of Madagascar and India, respectively, in exhibiting relatively simple, high-crowned, columnar cheek teeth. Other features (e.g., enamel-less dentition) are shared with disparate forms such as the Late Jurassic Fruitafossor and toothed xenarthrans (e.g., sloths), here attributed to convergence. Revised analyses of the depositional context for the holotype place it as having lived sometime between the late Turonian and latest Campanian (roughly 91–72 million years ago). This enhanced geochronological context helps to refine the palaeobiogeographical significance of Galulatherium among Cretaceous mammals in general and those from Gondwanan landmasses specifically.

5

Second specimen of Corriebaatar marywaltersae from the Lower Cretaceous of Australia confirms its multituberculate affinities

63%

Rich T. H. , Krause D. W. , Trusler P. , White M. A. , Kool L. , Evans A. R. , Morton S. , Vickers-Rich P.

Acta Palaeontologica Polonica

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2022

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tom 67

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nr 1