Data from: Diversity, phylogeny and biogeography of the South American ‘cardiomyine’ rodents (Hystricognathi, Cavioidea) with a description of two new species

‘Cardiomyine’ rodents are extinct large terrestrial Caviidae closely
related to capybaras, that inhabited large parts of South America during
the middle Miocene and Pliocene. They are mostly preserved as isolated
teeth, but also as skull and jaw fragments. Here we revise the taxonomy of
this group and describe two new species, each pertaining to one of the two
main late Miocene groups, represented by the genera Caviodon and
Cardiomys. This suggests that the diversity of ‘cardiomyines’ was higher
than previously thought. Among the specimens studied there are two almost
complete skulls; one from the Andalhuala Formation, Catamarca, and the
other from the Arroyo Chasicó Formation, Buenos Aires. The first, housed
in the Field Museum of Natural History, was originally catalogued as
Cardiomys ameghinorum, a common species for the late Miocene of
north-western Argentina (NOA), but is here transferred to the genus
Caviodon. This is the first mention of the genus for NOA, enlarging its
geographical distribution for the late Miocene. The second skull, assigned
to Cardiomys sp., is housed in the Museo de La Plata. Furthermore, from
the revision of the holotypes of the species of Caviodon (C.
multiplicatus, C. bravardi, C. (Lelongia) paranensis, C. angustidens and
C. scalai from the Conglomerado osífero of the Ituzaingó Formation; late
Miocene, Argentina) we propose their synonymy with the type species C.
multiplicatus, decreasing the specific diversity in that locality.
Finally, our phylogenetic analysis indicates that the species of
‘cardiomyines’ are paraphyletic, placing them in a basal position among
the Hydrochoerinae.