MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
artículos
Título:
new early Miocene octodontoid rodent (Hystricognathi, Caviomorpha) from Patagonia (Argentina) and a reassessment of the early evolution of Octodontoidea
Autor/es:
ARNAL, M.; KRAMARZ, A.; VUCETICH, M.G.; VIEYTES, EMMA.
Revista:
JOURNAL OF VERTEBRATE PALEONTOLOGY
Editorial:
SOC VERTEBRATE PALEONTOLOGY
Referencias:
Lugar: Lawrence; Año: 2014 p. 397 - 406
ISSN:
0272-4634
Resumen:
A new caviomorph rodent, Dudumus ruigomezi,
gen. et sp. nov., is described from the Sarmiento Formation, Trelew Member
(early Miocene), of the Argentinian Patagonia. This new taxon is represented by
upper and lower cheek teeth, mandible, and maxillary remains. It is
characterized by retention of deciduous premolar, and low-crowned and terraced lower
and upper cheek teeth with well-differentiated cusps, as in Caviocricetus
lucasi; uppermolariforms with themesolophule and metacone fused with the
posterior-most crest, as in C. lucasi; lower molars with lingual cusp
enlarged and metalophulid II longer in m2 than in m1and m3, as in Prospaniomys
priscus; and dp4 with metalophulid I separated from the metaconid and a
spur projecting posterolingually from the posterior wall of metalophulid I,
between the protoconid and anteroconid. The incisor enamel microstructure is
derived, with the interprismatic matrix perpendicular (at a right angle) to the
prisms, as in other octodontoids. A cladistic analysis corroborates that D.
ruigomezi represents an octodontoid rodent with unusual tooth morphology.
This analysis demonstrates that the early evolutionary history of Octodontoidea
was characterized by the differentiation of successive lineages that survived
until the early or middle Miocene, with no direct relationships with modern
Octodontidae and Echimyidae. This analysis also suggests that fossil taxa
previously classified as octodontoids are instead more closely related to the
other caviomorph rodents.