Macroscelideans (Myohyracinae and Rhynchocyoninae) from the late Oligocene Nsungwe formation of the Rukwa Rift Basin, southwestern Tanzania

Stevens, Nancy J., O'Connor, Patrick M., Mtelela, Cassy, and Roberts, Eric M. (2022) Macroscelideans (Myohyracinae and Rhynchocyoninae) from the late Oligocene Nsungwe formation of the Rukwa Rift Basin, southwestern Tanzania. Historical Biology, 34 (4). pp. 604-610.

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The fossil record of macroscelidean mammals is notoriously patchy, with a significant spatial and temporal gap separating faunas from the early Oligocene localities of northern Africa and the early Miocene localities of eastern and southern Africa. Here we describe fossil macroscelideans representing Myohyracinae and Rhynchocyoninae recovered from a rift-fill sequence of richly fossiliferous sandstones in the late Oligocene Nsungwe Formation in the Rukwa Rift Basin of southwestern Tanzania. Radiometrically dated to 25.2 Ma, a new Palaeogene myohyracine taxon (Rukwasengi butleri) is represented by a partial maxilla (RRBP 05409) preserving a lightly worn M2-M3. The M2 exhibits a less hypsodont and mesiodistally elongate morphology than the early Miocene Myohyrax oswaldi, and the three-rooted M3 exhibits a tiny mesially positioned fossette. A new rhynchocyonine (Oligorhynchocyon songwensis) is represented by specimens more brachyodont than the early Miocene Miorhynchocyon. Taken together these finds document a rare window into macroscelidean evolutionary history with diversification of the group near the Palaeogene-Neogene Transition (PNT). Continued exploration offers a refined perspective on mid-Cenozoic faunal and ecosystem dynamics on continental Africa, expanding opportunities for recognising trends in palaeobiological diversity across habitat types and through time.

Item ID: 70655
Item Type: Article (Research - C1)
ISSN: 1029-2381
Keywords: Afrotheria, Cenozoic, elephant shrew, mammal evolution, palaeoecology, Palaeogene, sengi
Copyright Information: © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way
Date Deposited: 06 Oct 2022 00:01
FoR Codes: 37 EARTH SCIENCES > 3705 Geology > 370506 Palaeontology (incl. palynology) @ 100%
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