New paper on a symbiotic relationship between tube-dwellers and bryozoans in the Silurian of Estonia

I have thoroughly enjoyed my many expeditions to the wondrous Baltic country of Estonia. My Estonian colleagues are fabulous, and I’ve been privileged to share the adventures with numerous students and Bill Ausich of Ohio State. Now during this global pandemic Estonia may as well be on the far side of the Moon. Maybe someday in the New Normal such travel will be possible again.

In the meantime, Olev Vinn has led our small international team to a new paper published today in the journal Lethaia. It is part of a long-term project describing the evolution of symbiosis among marine invertebrates. The abstract follows —

AbstractCornulites sp. and Fistulipora przhidolensis formed a symbiotic association in the Pridoli (latest Silurian) of Saaremaa Island, Estonia. This Cornulites sp.–F. przhidolensis association is the youngest example of cornulitid–bryozoan symbiosis. Symbiosis is indicated by intergrowth of both organisms. The cornulitids are completely embedded within the cystoporate bryozoan colony, leaving only their apertures free on the growth surface of the bryozoan. In terms of food competition, this association could have been slightly harmful to F. przhidolensis as Cornulites sp. may have been a kleptoparasite. There may have been a small escalation in the evolution of the endobiotic life mode of cornulitids as the number of such associations increased from the Ordovician to Silurian. It is likely that Palaeozoic bryozoan symbiosis reached its maximum in the Late Ordovician. Most of the symbiotic bryozoans in the Palaeozoic are trepostomes, and the diversity of symbiotic associations was also greatest among trepostomes.

The image above is Figure 2 from the paper. Caption: Cornulites sp. intergrown with Fistulipora przhidolensis from the lower Pridoli (Kaugatuma Formation) of Lõo cliff, Saaremaa, Estonia (GIT 666‐38). A, detailed view of bryozoan, B, Cornulites sp. [Corn] in cross section, C, D, apertures of Cornulites sp. [Corn] on the growth surface of Fistulipora.

If anyone wants a pdf, just send me an email.


Vinn, O., Ernst, A., Wilson, M.A. and Toom, U. 2021. Symbiosis of cornulitids with the cystoporate bryozoan Fistulipora in the Pridoli of Saaremaa, Estonia. Lethaia 54: 90–95.

About Mark Wilson

Mark Wilson is a Professor of Geology at The College of Wooster. He specializes in invertebrate paleontology, carbonate sedimentology, and stratigraphy. He also is an expert on pseudoscience, especially creationism.
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1 Response to New paper on a symbiotic relationship between tube-dwellers and bryozoans in the Silurian of Estonia

  1. Alex Crawford says:

    Thank you for demonstrating that bryozoans do not stop for viruses, Mark. Also, I now know what a kleptoparasite is. Great word.

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