IANIGLA   20881
INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
artículos
Título:
A poorly known rodent-like mammal (Pachyrukhinae, Hegetotheriidae, Notoungulata) from the Deseadan (Late Oligocene) of Argentina. Paleoecology, biogeography and radiation of the rodent-like ungulates in South America
Autor/es:
REGUERO, M. A.; DOZO, M. T.; CERDEÑO, E.
Revista:
JOURNAL OF PALEONTOLOGY
Referencias:
Año: 2007 vol. 81 p. 1298 - 1304
ISSN:
0022-3360
Resumen:
The cranial anatomy of the Deseadan species Medistylus dorsatus (Ameghino, 1903) is described based on new and complete
material from Cabeza Blanca (Chubut, Argentina). Medistylus is the largest of the Pachyrukhinae and the specimen described here is probably
the best-preserved pachyrukhine skull known in the Paleogene of South America. Previously, the validity of the species and its phylogenetic
affinities with Interatheriidae (Notoungulata, Typotheria) were ambiguous and not conclusive. The syntypes, now reported lost, were isolated
teeth poorly described by Ameghino in 1903. This almost complete skull with teeth provides more diagnostic features in order to complete the
knowledge of genus. Details about cranial and dental morphology allow the reassessment of Medistylus dorsatus and its inclusion within the
subfamily Pachyrukhinae (Hegetotheriidae, Notoungulata). Its cranial and dental specializations and the apparent sympatry with its close relativesMedistylus dorsatus (Ameghino, 1903) is described based on new and complete
material from Cabeza Blanca (Chubut, Argentina). Medistylus is the largest of the Pachyrukhinae and the specimen described here is probably
the best-preserved pachyrukhine skull known in the Paleogene of South America. Previously, the validity of the species and its phylogenetic
affinities with Interatheriidae (Notoungulata, Typotheria) were ambiguous and not conclusive. The syntypes, now reported lost, were isolated
teeth poorly described by Ameghino in 1903. This almost complete skull with teeth provides more diagnostic features in order to complete the
knowledge of genus. Details about cranial and dental morphology allow the reassessment of Medistylus dorsatus and its inclusion within the
subfamily Pachyrukhinae (Hegetotheriidae, Notoungulata). Its cranial and dental specializations and the apparent sympatry with its close relativesMedistylus is the largest of the Pachyrukhinae and the specimen described here is probably
the best-preserved pachyrukhine skull known in the Paleogene of South America. Previously, the validity of the species and its phylogenetic
affinities with Interatheriidae (Notoungulata, Typotheria) were ambiguous and not conclusive. The syntypes, now reported lost, were isolated
teeth poorly described by Ameghino in 1903. This almost complete skull with teeth provides more diagnostic features in order to complete the
knowledge of genus. Details about cranial and dental morphology allow the reassessment of Medistylus dorsatus and its inclusion within the
subfamily Pachyrukhinae (Hegetotheriidae, Notoungulata). Its cranial and dental specializations and the apparent sympatry with its close relativesMedistylus dorsatus and its inclusion within the
subfamily Pachyrukhinae (Hegetotheriidae, Notoungulata). Its cranial and dental specializations and the apparent sympatry with its close relatives
Prosotherium garzoni Ameghino, 1897 and Propachyrucos smithwoodwardi Ameghino, 1897 all imply a narrow niche partitioning among the
Pachyrukhinae during the Deseadan (late Oligocene). The occurrence of three euhypsodont genera of Pachyrukhinae in the Deseadan of
Patagonia reflects the major radiation of the rodentlike ungulates in the Cenozoic of South America and suggests a great paleoenvironmental
difference between the late Oligocene faunas of Patagonia and those from Bolivia and Uruguay, where they did not live.Ameghino, 1897 and Propachyrucos smithwoodwardi Ameghino, 1897 all imply a narrow niche partitioning among the
Pachyrukhinae during the Deseadan (late Oligocene). The occurrence of three euhypsodont genera of Pachyrukhinae in the Deseadan of
Patagonia reflects the major radiation of the rodentlike ungulates in the Cenozoic of South America and suggests a great paleoenvironmental
difference between the late Oligocene faunas of Patagonia and those from Bolivia and Uruguay, where they did not live.