Syringammina fragilissima is a xenophyophore found off the coast of Scotland, near Rockall. It is the largest single-cell organism known, at up to 20 centimetres (8 in) across. It was the first xenophyophore to be described, after being discovered in 1882 by the oceanographer John Murray.
|Fig. 1. Syringammina fragilissima. Natural size, a, side view of a fragment representing about half an entire specimen; aa, original surface of specimen; b, ventral view of same specimen, showing uneven fractured surface near the middle of the test; dotted line shows approximately the original outline of the test. (After Brady)|
2. Syringammina fragilissima. ×8. Portion of a radial section, showing at c one of the smaller secondary canals, and at cc one of the concentric reticulated partitions. (After Brady.)
The cell grows into hundreds of branched and interconnecting tubes, which secrete an organic cement to collect particles of sediment and sand, forming a crusty structure called the test. As the test grows, the cell withdraws from parts of it, which are then colonised by other organisms, such as nematodes. The cell is multinucleate (it has multiple nuclei).
It is not known how the organism feeds or reproduces. However, it has been shown to have high concentrations of lipids within its cytosol, which suggests that it may feed on bacteria from the sediment that makes up the "sand tubes."
- Brady, H. B. (1883). Note on Syringammina, a New Type of Arenaceous Rhizopoda. Proceedings of the Royal Society of London. 35(224-226): 155-161., available online at https://doi.org/10.1098/rspl.1883.0031
- "As large as life". New Scientist. 2157. October 24, 1998.
- Michael Marshall (February 3, 2010). "Zoologger: 'Living beach ball' is giant single cell". New Scientist.
- J. Alan Hughes & Andrew J. Gooday (2004). "Associations between living benthic foraminifera and dead tests of Syringammina fragilissima (Xenophyophorea) in the Darwin Mounds region (NE Atlantic)". Deep-Sea Research Part I: Oceanographic Research Papers. 51 (11): 1741–1758. Bibcode:2004DSRI...51.1741H. doi:10.1016/j.dsr.2004.06.004.
- Laureillard, J., L. Méjanelle, and M. Sibuet. "Use of Lipids to Study the Trophic Ecology of Deep-sea Xenophyophores." Marine Ecology Progress Series 270 (2004): 129-40. Print.