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Tendencias fanerozoicas en la diversidad global de los invertebrados marinos
John Alroy1, Martin Aberhan, David J Bottjer
1National Center for Ecological Analysis and Synthesis, University of California-Santa Barbara, 735 State Street, Santa Barbara, CA 93101, USA. alroy@nceas.ucsb.edu
Science (New York, N.Y.)
|July 5, 2008
Resumen
La diversidad de invertebrados marinos muestra un aumento modesto, no una fuerte radiación, después de mediados del Cretácico. Los análisis modernos revelan una riqueza global y local estable y gradientes latitudinales consistentes a lo largo de las eras paleozoica y cenozoica.
Área de la Ciencia:
- Paleontología Paleontología.
- Biología Marina Biología Marina.
- Biología evolutiva Biología evolutiva.
Sus antecedentes:
- Investigaciones anteriores sugirieron una radiación significativa de los invertebrados marinos durante los períodos Cretácico y Cenozoico.
- Este patrón percibido se basó en métodos analíticos y conjuntos de datos más antiguos.
Objetivo del estudio:
- Para reevaluar el patrón de diversificación de los invertebrados marinos utilizando un conjunto completo de datos de ocurrencia de fósiles.
- Para determinar si la radiación pronunciada propuesta anteriormente está respaldada por técnicas analíticas modernas.
Principales métodos:
- Utilizó un nuevo conjunto de datos de 3,5 millones de ocurrencias fósiles.
- Empleó la estandarización del muestreo y métodos de conteo robustos para el análisis.
- Resultados comparados de protocolos analíticos más antiguos con métodos más nuevos y estandarizados.
Principales resultados:
- El patrón de radiación empinada solo se replica utilizando protocolos analíticos más antiguos.
- Los análisis con la estandarización del muestreo y el recuento robusto revelan un aumento modesto de la diversidad sin una tendencia clara después de mediados del Cretácico.
- La diversidad de invertebrados marinos en el Neogeno fue menos del doble que la de mediados del Paleozoico, a nivel global y local.
- La relación entre la riqueza global y la local se mantuvo relativamente constante.
- Un gradiente de diversidad latitudinal era evidente incluso en el Paleozoico temprano.
Conclusiones:
- La radiación pronunciada previamente asumida de los invertebrados marinos es un artefacto de los métodos analíticos más antiguos.
- Los análisis modernos y rigurosos indican un aumento más moderado en la diversidad de invertebrados marinos.
- Los patrones de diversidad latitudinal y la relación entre la riqueza global y local han sido estables a lo largo de largas escalas de tiempo geológicas.
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