Reappraisal of the giant caviomorph rodent <i>Phoberomys burmeisteri</i> (Ameghino, 1886) from the late Miocene of northeastern Argentina, and the phylogeny and diversity of Neoepiblemidae

Abstract

<i>Phoberomys</i> is a giant caviomorph rodent included in the extinct Neoepiblemidae. It is recorded in the late Miocene-Pliocene of South America (Argentina, Venezuela, Brazil and Peru), and is one of the largest rodents that have ever lived. In this contribution we study specimens of <i>Phoberomys</i> from the ‘Mesopotamiense’, late Miocene of Entre Ríos Province (Argentina), including several unpublished specimens and the holotypes of the five nominal species (<i>Ph. burmeisteri</i>, <i>Ph. praecursor</i>, <i>Ph. insolita</i>, <i>Ph. lozanoi</i> and <i>Ph. minima</i>) previously recognised for this unit. Our study indicates that all Mesopotamian specimens belong to <i>Phoberomys burmeisteri</i>, and that the differences among them reveal individual and ontogenetic variation. Our phylogenetic analysis indicates that Neoepiblemidae is monophyletic and includes <i>Phoberomys</i>, <i>Neoepiblema</i>, and <i>Perimys</i>. <i>Phoberomys</i> species are recovered as a clade, which is more closely related to <i>Neoepiblema</i> than to the Patagonian <i>Perimys</i>. In addition, our study shows that <i>Eusigmomys</i> is not a Neoepiblemidae, but a Dinomyidae.