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Swiss Journal of Palaeontology

, Volume 131, Issue 2, pp 201–210 | Cite as

A new bryozoan genus from the Jurassic of Switzerland, with a review of the cribrate colony-form in bryozoans

  • Paul D. Taylor
Article

Abstract

Very few Jurassic bryozoans have been recorded from Switzerland. The discovery in the collections of the Universität Zurich of a very distinctive cyclostome bryozoan from the Aalenian of Gelterkinden in the Basel-Country Canton, warrants the creation of a new monospecific genus, Rorypora gen nov. The type species of Rorypora, Diastopora retiformis Haime, 1854, was originally described from the French Bajocian. This genus has a ‘cribrate’ colony-form comprising flattened bifoliate fronds that bifurcate and coalesce regularly to enclose ovoidal lacunae. Unlike the much commoner fenestrate colony-form, apertures of feeding zooids open on both sides of the fronds. The taxonomic distribution of cribrate colonies in bryozoans is reviewed. They are most common in Palaeozoic ptilodictyine cryptostomes but are also found among Palaeozoic cystoporates and Cenozoic cheilostomes, as well as the single known cyclostome example described here. Cribrate colonies therefore provide a striking example of multiple evolutionary convergence. In contrast to fenestrate colony-forms, feeding currents cannot be channelled through the lacunae in cribrate colonies to generate a one-way flow of water for efficient suspension feeding. Instead, the holes are inferred to be the locations of chimneys over which exhalent currents are vented in opposite directions on either side of the planar colony.

Keywords

Cyclostomata Convergent evolution Functional morphology Feeding 

Notes

Acknowledgments

Dr Heinz Furrer (Paläontologisches Institut und Museum, Universität Zurich) is thanked for allowing me access to the collections under his care and arranging a loan. I am very grateful to work experience student Robyn Pointer (Imperial College, London) for compiling data on cribrate bryozoans, and to two anonymous reviewers for helpful comments.

Supplementary material

13358_2011_27_MOESM1_ESM.doc (100 kb)
Supplementary material 1 (DOC 100 kb)

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Copyright information

© Crown Copyright 2011

Authors and Affiliations

  1. 1.Department of PalaeontologyNatural History MuseumLondonUK

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