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Un mamífero jurásico de América del Sur
Oliver W M Rauhut1, Thomas Martin, Edgardo Ortiz-Jaureguizar
1Museo Paleontológico Egidio Feruglio, Fontana 140, 9100 Trelew, Argentina.
Nature
|March 15, 2002
Resumen
Un nuevo fósil de mamífero jurásico de América del Sur revela una diversificación temprana de Australosphenida. Este hallazgo pone de relieve distintas faunas de mamíferos del hemisferio sur durante el período Jurásico.
Área de la Ciencia:
- Paleontología Paleontología.
- Biología evolutiva Biología evolutiva.
- Evolución de los mamíferos Evolución de los mamíferos
Sus antecedentes:
- El período Jurásico es crucial para la evolución y diversificación de los primeros mamíferos.
- El registro fósil de los mamíferos del Jurásico, especialmente de Gondwanalandia (continentes del sur), es escaso.
- Los descubrimientos anteriores se limitaron a Tanzania, Madagascar y Argentina (por vías navegables).
Objetivo del estudio:
- Para informar sobre el descubrimiento de un nuevo fósil de mamífero jurásico de América del Sur.
- Para identificar el significado taxonómico y evolutivo del fósil.
- Comprender la distribución y diversificación de los primeros mamíferos en Gondwana.
Principales métodos:
- Descubrimiento de fósiles y análisis de un dentario de mamífero (maxilar inferior).
- Datación geológica para determinar la edad del Jurásico Medio y Tardío.
- Análisis comparativo con grupos de mamíferos conocidos, en particular Australosphenida.
Principales resultados:
- Un dentario fósil de la Patagonia representa el primer mamífero jurásico de América del Sur.
- El fósil pertenece a Australosphenida, un grupo de Gondwana con molares tribosfénicos convergentes.
- La evidencia sugiere que Australosphenida se diversificó y se extendió por Gondwanalandia antes de que terminara el Jurásico.
Conclusiones:
- Este descubrimiento amplía el rango geográfico conocido de mamíferos jurásicos en el hemisferio sur.
- Apoya la hipótesis de que los Australosphenida estaban muy extendidos y diversos en Gondwana.
- La fauna de mamíferos del Jurásico en el hemisferio sur era distinta de la del hemisferio norte.
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