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Fragilariopsis diatom evolution in Pliocene and Pleistocene Antarctic shelf sediments

Micropaleontology

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Abstract

The late Pliocene – early Pleistocene sediment record in the AND-1B core from the McMurdo Sound, Ross Sea, Antarctica, displays a rich diversity and high abundance of diatoms, including several new morphologies within the genus Fragilariopsis. These new morphologies exhibit similarities to the extinct late Miocene/early Pliocene species Fragilariopsis aurica Gersonde and Fragilariopsis praecurta Gersonde, as well as to the modern sea ice-associated species Fragilariopsis ritscheri Hustedt and Fragilariopsis obliquecostata van Heurck. From the diverse morphologies present, we use light microscopy and scanning electron microscopy to identify and describe the characteristics of three new taxa, Fragilariopsis laqueata Riesselman, Fragilariopsis bohatyi Sjunneskog et Riesselman, and Fragilariopsis robusta Sjunneskog, which are common in the diatom-bearing intervals from ~3.2 to 1.95 Ma. Comparisons with extant and extinct species are made to assess possible environmental affinities, evolutionary relationships, and potential for future biostratigraphic utility. This complex of newmorphologies diversified as conditions cooled during the Pliocene, then went into decline as heavy sea ice conditions of the Pleistocene were established. Only the lineage of F. robusta appears to continue into the late Pleistocene, where it is interpreted to have evolved into F. obliquecostata.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Fragilariopsis diatom evolution in Pliocene and Pleistocene Antarctic shelf sediments
Series title:
Micropaleontology
Volume
58
Issue:
3
Year Published:
2012
Language:
English
Publisher:
Micropaleontology Press
Contributing office(s):
Eastern Geology and Paleoclimate Science Center
Description:
17 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Micropaleontology
First page:
273
Last page:
289
Country:
Antarctica