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Evidencia de bajas temperaturas y diversidad biológica en latitudes altas del Cretácico de Australia
Science (New York, N.Y.)
|December 9, 1988
Resumen
La Australia polar cretácea albergaba una vida diversa, incluidos los dinosaurios endémicos, en un clima fresco y estacional. Esto sugiere que el frío y la oscuridad no fueron los únicos impulsores de la extinción de los dinosaurios.
Área de la Ciencia:
- Paleontología Paleontología.
- Paleoclimatología Paleoclimatología
- La biogeografía es la biogeografía.
Sus antecedentes:
- El período Cretácico (105-130 millones de años atrás) vio diversos ecosistemas terrestres en todo el mundo.
- Las regiones polares a menudo se perciben como entornos hostiles, que potencialmente limitan la vida compleja.
Objetivo del estudio:
- Para investigar la composición y el clima de los ecosistemas polares del Cretácico en el sureste de Australia.
- Analizar las implicaciones de esta biota de altas latitudes para las teorías de supervivencia y extinción de los dinosaurios.
Principales métodos:
- Análisis de vertebrados fosilizados, invertebrados y plantas (>150 taxones).
- Análisis de isótopos de oxígeno de calcita diagenética para la reconstrucción de paleotemperatura.
- Dendrocronología de maderas fósiles para inferir la estacionalidad.
Principales resultados:
- Descubrimiento de una biota diversa que incluye hipsilophodontids y terópodos endémicos (por ejemplo, Allosaurus).
- La reconstrucción del paleoclima indica un clima fresco (temperatura media anual <5°C) y estacional.
- Evidencia de una supervivencia prolongada para taxones como los anfibios labyrinthodont.
Conclusiones:
- La región polar del Cretácico del sureste de Australia soportaba un rico ecosistema no tropical.
- La adaptabilidad de los dinosaurios a las condiciones de altas latitudes desafía el papel primordial del frío y la oscuridad en su extinción.
- El aislamiento geográfico probablemente jugó un papel en la supervivencia prolongada de ciertos taxones.
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