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GEOREF RECORD

Paleoecology and ecology of xenophyophores

Lisa A. Levin
Paleoecology and ecology of xenophyophores
Palaios (February 1994) 9 (1): 32-41

Abstract

Xenophyophores are large (several mm to 25 cm diameter), agglutinating protozoans, found primarily in the deep sea. Tests range from simple fans, discs or mudballs, to elaborately folded or reticulated forms, and often contain specific particle types or sizes. Xenophyophore densities are highest on sloped sediments associated with seamounts, continental slopes, canyons and trenches, and beneath productive surface waters. Most forms live as epibenthos on hard or soft substrates, feeding on surface deposits and suspended particles, but one endobenthic genus has been described. Modern xenophyophores enhance particle flux to the seabed, creating local regions of intense radiotracer and metazoan activity. Features key to xenophyophore identification in the fossil record include distinct test morphologies that sometimes involve incorporation of globigerinacean tests, sandwich-like structure in cross section, concentrations of barite (found within the protoplasm), and the presence of fecal strands containing many 10 to 20 mm fecal pellets having enhanced Pb contents. While xenophyophores have no confirmed fossil record, modern structures resembling the ichnogenus Paleodictyon are made by endobenthic xenophyophores in the genus Occultammina. Parallel distributions, morphologies and behaviors have been proposed for some graphoglyptid trace fossils, and for some xenophyophores in the families Syringamminidae and Reticulamminidae. Both occur in the deep sea, have regular or irregular network morphologies, and have been proposed to garden bacteria, trap meiofauna, or suspension feed. Fossils previously regarded as phylloid and fucoid algae, and several species of Aschemonella, previously regarded as foraminiferids, have lifestyles and morphologies consistent with those of modern epibenthic xenophyophores. Confirmation of xenophyophore presence in stratigraphic sequences could provide paleohabitat information and help elucidate the origins of this protozoan group.


ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 9
Serial Issue: 1
Title: Paleoecology and ecology of xenophyophores
Author(s): Levin, Lisa A.
Affiliation: Scripps Institution of Oceanography, La Jolla, CA, United States
Pages: 32-41
Published: 199402
Text Language: English
Publisher: Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States
References: 50
Accession Number: 1995-057754
Categories: Invertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 plate
Source Note: Advances in deepsea paleoecology
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by SEPM (Society for Sedimentary Geology), Tulsa, OK, United States
Update Code: 199521
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