Mammalia - Rodentia - Octodontidae

Emended diagnosis. Octodontoid larger than Neophanomys, Acaremys minutissimus Ameghino, 1887 and Acarechimys leucotheae. Cranium with the tip of the lateral process of the supraoccipital dorsal to the mastoid process. Mandible proportionally lower than that of Neophanomys, with the chin process slightly more posterior than in A. minutissimus, at the level of the anterior part of the dp4. Masseteric crest descending from he posterior part of the notch for the tendon of m. masseter medialis, pars infraorbitalis. Notch subhorizontal. Lateral crest straight, descending toward the masseteric notch following the same direction as the anterior margin of coronoid apophysis. Lower incisor very slender, with enamel more labially extended than in A. minutissimus and Neophanomys. Fourth deciduous molars (DP4/dp4) functional throughout life. Upper molars tetralophodont, with the mesoflexus/fossette more persistent and wider than the paraflexus/fossette and metaflexus/fossette. Mesolophule originated from the mure, and with its labial end joined to the medial wall of the metacone area in M12. DP4 with the mesolophule not reduced. Juvenile dp4 pentalophodont, with a principal oblique spur of the metalophulid II, and the mesolophid anterolingually oriented; adult dp4 bilobed or suboval. m13 trilophodont in non-senile specimens; atypically, remnant tetralophodonty in m1; m12 with protoconid and hypoconid areas labially extended and acuminate, and mesoflexid more persistent than metaflexid. LSID. urn:lsid:zoobank.org:act:56D865C2-81BC-4F74-9778-0C507 877D7EB

Full reference: P. Piñero, D. H. Verzi, A. I. Olivares, C. I. Montalvo, R. L. Tomassini and A. Fernández Villoldo. 2021. Evolutionary pattern of Metacaremys gen. nov. (Rodentia, Octodontidae) and its biochronological implications for the late Miocene and early Pliocene of southern South America. Papers in Palaeontology 7(4):1859-1917

Parent taxon: Octodontidae according to P. Piñero et al. 2021

Sister taxa: Eoctodon, Eucoelophorus, Massoiamys, Octodontinae, Octodontomys, Octomys, Palaeoctodon, Phthoramys, Phtoramys, Pithanotomys, Plataeomys, Pseudoplataeomys

Subtaxa: Metacaremys calfucalel Metacaremys dimi Metacaremys primitiva

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Type: Metacaremys primitiva

Ecology: ground dwelling herbivore

Distribution:

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Specimen images are retrieved through the ePANDDA API.