On the Demise of the Early Paleogene Morozovella velascoensis Lineage: Terminal
The extinction of the Morozovella velascoensis lineage, a group of planktonic foraminifera that dominated tropical assemblages for;6.3 m.y., is investigated using an upper Paleocene/lower Eocene section from the central Pacific Ocean (ODP Site 865). Uppermost stratigraphic occurrenc-es of the lineag...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.567.2017 http://www.es.ucsc.edu/~jzachos/pubs/KBZ_2001.pdf |
| Summary: | The extinction of the Morozovella velascoensis lineage, a group of planktonic foraminifera that dominated tropical assemblages for;6.3 m.y., is investigated using an upper Paleocene/lower Eocene section from the central Pacific Ocean (ODP Site 865). Uppermost stratigraphic occurrenc-es of the lineage consist solely of diminutive M. edgari, a species roughly half the size of its ancestor, M. velascoensis. Eigenshape analysis indicates that adult specimens of M. edgari are morphologically similar to small, presumably ju-venile, forms of M. velascoensis. The overall stratigraphic succession, where the uppermost occurrences of a lineage are represented by relict populations of minute, juvenilized forms, is consistent with a process called ‘‘terminal progen-esis.’ ’ Various lines of evidence indicate that stress-induced size reduction foreshadowed the extinction of other plank- |
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