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Xenophyophores, giant foraminifera, are distinctive members of the deep-sea megafauna that accumulate large masses of waste material (‘stercomare’) within their agglutinated tests, and organise their cells as branching strands enclosed within an organic tube (the ‘granellare’ system). Using non-destructive, three-dimensional micro-CT imaging we explored these structures in three species from the abyssal eastern Pacific Clarion-Clipperton Zone (CCZ). In Psammina spp., the low-density stercomare occupied much of the test interior, while high-density granellare strands branched throughout the structure. In Galatheammina sp. the test comprised a mixture of stercomare and test particles, with the granellare forming a web-like system of filaments. The granellare occupied 2.8-5.1%, the stercomare 72.4-82.4%, and test particles 14.7-22.5%, of the ‘body’ volume in the two Psammina species. The corresponding proportions in Galatheammina sp. were 1.7% (granellare), 39.5% (stercomare) and 58% (test particles). These data provide a potential basis for estimating the contribution of xenophyophores to seafloor biomass in areas like the CCZ where they dominate the megafauna. As in most xenophyophore species, the granellare hosted huge numbers of tiny barite crystals. We speculate that these help to support the extensive granellare system, as well as reducing the cell volume and lightening the metabolic burden required to maintain it.

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Cite this as

Andrew Gooday; Dan Sykes; Adrian Glover (2018). Xenophyophores [Data set]. Natural History Museum.
Retrieved: 01:54 20 Jul 2024 (UTC) BibTeX

Additional Info

Field Value
Affiliation National Oceanography Centre; University of Manchester; Natural History Museum, London
Primary contributors
Gooday, Andrew;
Sykes, Dan;
Glover, Adrian ( 0000-0002-9489-074X)
Other contributors
Last updated 8 April 2019
Last resource update 8 April 2019 (Xenophyophores summary data)
Created 30 July 2018
License License not specified