Michael Kaminski: The Early Evolution of Multichambered Foraminifera - new results from Saudi Arabia
Автор: TMS-Cushman Foram Seminars
Загружено: 2023-07-05
Просмотров: 286
Описание: Abstract: New findings of multichambered foraminifera in the lower Paleozoic of Saudi Arabia shed new light on the evolution of the globothalamids, the multichambered foraminifera. I will report on the findings of multichambered agglutinated foraminifera belonging to the hormosinids and lituolids in the Ordovician and Silurian of Saudi Arabia. The presence of hormosinids in the upper Ordovician Ra’an Shale confirm the idea of a middle to late Ordovician origin for this family of multichambered foraminifera. The finding of the genera Ammobaculites and Sculptobaculites in the lower Silurian (Aeronian) of the Qusaiba Shale pushes back the known origin of the order lituolida by about 40 million years. These findings suggest that the transition from two-chambered forms (Pawlowski’s tubothalamids) to the multichambered forms (globothalamids) was much more rapid than previously thought. It would appear that a major evolutionary event among the foraminifera took place in the Early Silurian in Gondwana following the first of Sepkoski’s “Big Five” mass extinction events.
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