If a komokiacean turns up in a phylogeny, will anybody notice?
Published 13 July 2010
It’s possible that only one reader will care about this. But this is one minor detail that I came across while researching yesterday’s post.
Komokiacea are large deep-sea branching protists that are expected, but not conclusively demonstrated, to belong or be related to Foraminifera. Attempts to extract molecular data for komokiaceans have, to date, failed miserably (Lecroq et al. 2009). Or have they?
In a paper written by Gooday et al. (1997), my attention was caught by the offhand comment: “We include Rhizammina algaeformis Brady 1879 [another deep-sea branching foram] within the Komokiacea on the basis of its ‘softpart’ organization“. This relationship, it turns out, had originally been proposed by Cartwright et al. (1989). If this assignment is correct then komokiaceans have been appearing in molecular phylogenies for some years and nobody has been paying a blind bit of notice! Even more interestingly, Pawlowski et al. (2003) placed Rhizammina as sister to the xenophyophore Syringammina. Xenophyophores resemble komokiaceans both in being large branchers and in the sequestration of stercomata (faecal pellets) within their structure. A close relationship between the two groups would be quite credible. However, no other authors to date appear to have commented on Cartwright et al.‘s reclassification of Rhizammina so I have no idea whether it’s regarded as credible.
Discuss.
References
Cartwright, N. G., A. J. Gooday & A. R. Jones. 1989. The morphology, internal organization, and taxonomic position of Rhizammina algaeformis Brady, a large, agglutinated, deep-sea foraminifer. Journal of Foraminiferal Research 19 (2): 115–125.
Gooday, A. J., R. Shires & A. R. Jones. 1997. Large, deep-sea agglutinated Foraminifera; two differing kinds of organization and their possible ecological significance. Journal of Foraminiferal Research 27 (4): 278–291.
Lecroq, B., A. J. Gooday, T. Cedhagen, A. Sabbatini & J. Pawlowski. 2009. Molecular analyses reveal high levels of eukaryotic richness associated with enigmatic deep-sea protists (Komokiacea). Marine Biodiversity 39: 45–55.
Pawlowski, J., M. Holzmann, J. Fahrni & S. L. Richardson. 2003. Small subunit ribosomal DNA suggests that the xenophyophorean Syringammina corbicula is a foraminiferan. Journal of Eukaryotic Microbiology 50: 483–487.