Additions to the knowledge of Urumaquia robusta (Xenarthra, Phyllophaga, Megatheriidae) from the Urumaco Formation (Late Miocene), Estado Falcón, Venezuela.

CARLINI A.A., D. BRANDONI, R. SÁNCHEZ

PALAEONTOLOGISCHE ZEITSCHRIFT

SPRINGER HEIDELBERG

Año: 2008 vol. 82 p. 153 - 162

0031-0220

Abstract: We describe new remains of Urumaquia robusta CARLINI, BRANDONI & SÁNCHEZ, 2006, which signifi - cantly improve the knowledge of the species and allow a more precise discussion about the relationships with the rest of the South American Megatheriinae. The new remains (ulna, phalanx, femora, patella, tibia, astragalus, navicular, metatarsals IV–V) described here suggest close affi nities of this taxon with the species of Pyramiodontherium and with Megatheriops rectidens, based on morphological similarities of the ulna (length, gracility), femur (general morphology, shape of the medial margin), and astragalus (angle between the discoidal and odontoid facets, position of the navicular facet with respect to the discoidal facet). In fact, the shape of femoral medial margin is a shared derived character among Urumaquia, Pyramiodontherium and Megatheriops. However, and despite the increasing information concerning Tertiary species, their phylogenetic relationships are only partially understood.