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

• We here establish a newmammaliaform genus and species, Galulatheriumjenkinsi (Mammalia), from the UpperCretaceous Galula Formation in the Rukwa Rift Basin of southwestern Tanzania. Thisrepresents the first named taxon of a mammaliaform from the entire Late Cretaceous,an interval of 34 million years, of continental Afro-Africa. Preliminary studyof the holotype (a partial dentary) resulted in tentative assignation to the Gondwanatheria,a poorly known, enigmatic clade of Late Cretaceous–Paleogene Gondwanan mammals (Krauseet al. 2003). The application of advanced imaging (µCT) and visualizationtechniques permits a more detailed understanding of key anatomical features of thenew taxon. CT analysis reveals that the lower dentition consisted of a large,procumbent lower incisor and four cheek teeth, all which are ever growing(hypselodont). Importantly, all of the teeth appear to have been devoid ofenamel during life. Comparisons conducted with a range of Mesozoic and selectedCenozoic mammaliaform groups demonstrates that a number of features (e.g.,enamel-less and ever-growing teeth, columnar cheek teeth with relatively simpleocclusal morphology) expressed in Galulatheriumare reminiscent of disparate groups, making taxonomic assignment difficult. Hereinwe 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, which exhibit relatively simple, high-crowned, columnar cheek teeth.Other features (e.g., enamel-less dentition) shared with disparate forms suchas the Late Jurassic Fruitafossor andvarious xenarthrans (e.g., sloths) are attributed to convergence. Detailed analysesof the depositional context for the type and only specimen place it as havinglived sometime between the late Turonian and latest Campanian (roughly 91–72million years ago). This enhanced geochronological context helps to refine thepalaeobiogeographical significance of Galulatheriumamong Cretaceous mammals in general and those of Gondwanan landmassesspecifically.

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NATURVETENSKAP  -- Biologi -- Zoologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Zoology (hsv//eng)

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Diversity of life

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