An unpredicted ancient colonization of the West Indies by North American rodents: dental evidence of a geomorph from the early Oligocene of Puerto Rico

Abstract

This contribution provides the raw files for the µCT-scan data and renderings of the three-dimensional digital models of two fossil teeth of a geomyin geomorph rodent (Caribeomys merzeraudi), discovered from lower Oligocene deposits of Puerto Rico, San Sebastian Formation (locality LACM Loc. 8060). These fossils were described, figured and discussed in the following publication: Marivaux et al. ( 2021), An unpredicted ancient colonization of the West Indies by North American rodents: dental evidence of a geomorph from the early Oligocene of Puerto Rico. Papers in Palaeontology.

Incisor enamel microstructure of West Indian caviomorph hystricognathous rodents (Octodontoidea and Chinchilloidea)

“…Their possible long evolutionary history on the islands needs to be demonstrated/documented by paleontological data, especially for the Miocene epoch. It is in this sense that we are now concentrating our efforts in the field, in order to further document the fossil record of chinchilloids, but also of echimyid octodontoids (capromyines and heteropsomyines), as well as other island vertebrates (e.g., Blackburn et al 2020;Marivaux et al 2021;Viñola Lopez et al 2022). UM N312, Chinchilla sp.…”

“…This discovery has therefore raised the critical question of a possible link between these Paleogene Puerto Rican chinchilloids and some of the Pleistocene-Holocene West Indian "giant hutias" ("heptaxodontids", especially Amblyrhiza and Elasmodontomys) for which a chinchilloid status was also supported from compatible dental morphology and incisor enamel microstructure evidence . Accordingly, the possibility of a greater antiquity of some of the Quaternary "giant hutias" has been seriously considered, as well as the existence of a pattern of multiple and time-staggered dispersal events to explain the natural colonization of the West Indies by rodents (see Marivaux et al , 2021.…”

The oldest known record of a ground sloth (Mammalia, Xenarthra, Folivora) from Hispaniola: evolutionary and paleobiogeographical implications

“…Although efforts aimed at collecting fossils of terrestrial vertebrates in Neogene localities are ongoing (e.g., Rio Guatemala in Puerto Rico; Vélez-Juarbe et al, 2014;Blackburn et al, 2020;Marivaux et al, 2020Marivaux et al, , 2021, future fieldwork in Hispaniola and across the Greater Antilles is needed. Filling the temporal and geographical gaps in the fossil record between the Eocene-Oligocene and the Quaternary terrestrial fauna would lead to an improved understanding of the origins and evolution of sloths and other components of the Greater Antillean vertebrate fauna.…”

3D models related to the publication: An unpredicted ancient colonization of the West Indies by North American rodents: dental evidence of a geomorph from the early Oligocene of Puerto Rico

“…1A-C] and a pristine deciduous lower premolar [LACM 162478;Fig. 1D-F]) have allowed the description of a new small-bodied geomyin geomorph (Caribeomys merzeraudi Marivaux et al, 2021). This discovery is the only evidence of the presence of this rodent group in the West Indies in the past.…”

“…This unexpected rodent adds to the few cases of Antillean terrestrial vertebrates of North American origins. Without clear subaerial land connections between both landmasses, an overwater dispersal probably occurred to explain the mid-Paleogene colonization of the West Indies by geomorph rodents (see Marivaux et al, 2021).…”