title: A new enigmatic Late Miocene mylodontoid sloth from northern South America.
abstract: A new genus and species of sloth (Eionaletherium tanycnemius gen. et sp. nov.) recently collected from the Late Miocene Urumaco Formation, Venezuela (northern South America) is herein described based on a partial skeleton including associated femora and tibiae. In order to make a preliminary analysis of the phylogenetic affinities of this new sloth we performed a discriminate analysis based on several characters of the femur and tibia of selected Mylodontoidea and Megatherioidea sloths. The consensus tree produced indicates that the new sloth, E. tanycnemius, is a member of the Mylodontoidea. Surprisingly, the new taxon shows some enigmatic features among Neogene mylodontoid sloths, e.g. femur with a robust lesser trochanter that projects medially and the straight distinctly elongated tibia. The discovery of E. tanycnemius increases the diversity of sloths present in the Urumaco sequence to ten taxa. This taxon supports previous studies of the sloth assemblage from the Urumaco sequence as it further indicates that there are several sloth lineages present that are unknown from the better sampled areas of southern South America.
authors.affiliation: Instituto Venezolano de Investigaciones Científicas (IVIC), Laboratorio de Paleontología-Centro de Ecología, Km 11 de la Carretera Panamericana , Edo. Miranda. Aptdo. 21.827, Caracas Cod. Postal 1020-A, Venezuela.
authors.forename: Ascanio D
authors.initials: AD
authors.lastname: Rincón
authors.affiliation: Museum Management Program, National Park Service , 1201 Oakridge Drive, Fort Collins, CO 80525, USA.
authors.forename: H Gregory
authors.initials: HG
authors.lastname: McDonald
authors.affiliation: Instituto Venezolano de Investigaciones Científicas (IVIC), Laboratorio de Paleontología-Centro de Ecología, Km 11 de la Carretera Panamericana , Edo. Miranda. Aptdo. 21.827, Caracas Cod. Postal 1020-A, Venezuela.
authors.forename: Andrés
authors.initials: A
authors.lastname: Solórzano
authors.affiliation: Instituto Venezolano de Investigaciones Científicas (IVIC), Laboratorio de Paleontología-Centro de Ecología, Km 11 de la Carretera Panamericana , Edo. Miranda. Aptdo. 21.827, Caracas Cod. Postal 1020-A, Venezuela.
authors.forename: Mónica Núñez
authors.initials: MN
authors.lastname: Flores
authors.affiliation: Instituto Venezolano de Investigaciones Científicas (IVIC), Laboratorio de Paleontología-Centro de Ecología, Km 11 de la Carretera Panamericana , Edo. Miranda. Aptdo. 21.827, Caracas Cod. Postal 1020-A, Venezuela.
authors.forename: Damián
authors.initials: D
authors.lastname: Ruiz-Ramoni
keywords: Eionaletherium tanycnemius; Mylodontoidea; Urumaco Formation; Venezuela