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Eocene and Oligocene ceriantharian tubes

Published online by Cambridge University Press:  03 July 2025

Steffen Kiel*
Affiliation:
Swedish Museum of Natural History, Department of Palaeobiology, Box 50007, 10405 Stockholm, Sweden
James L. Goedert
Affiliation:
Burke Museum of Natural History and Culture, University of Washington, Seattle, Washington 98195, USA
*
Corresponding author: Steffen Kiel; Email: steffen.kiel@nrm.se

Abstract

Three fossil tube fragments from middle Eocene to late Oligocene strata in western Washington State, USA, are here interpreted as those of ancient Ceriantharia (Hexacorallia, Cnidaria). The tube fragments are 3–6 mm in diameter, up to 60 mm long, and the surfaces show an overlapping, fibrous knitted pattern. This surface pattern resembles that of the extant ceriantharid Cerianthus membranaceus. One specimen has numerous benthic foraminiferans associated with, and apparently even embedded in, the tube wall, analogous to some extant Ceriantharia. These fossils likely represent the first fossil Ceriantharia and indicate that their present-day mode of tube construction using ptychocysts was established at latest by the middle Eocene.

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Articles
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of Paleontological Society
Figure 0

Figure 1. Eocene ceriantharian tubes from the Makah and Hoko River formations in Washington State, USA, and extant ceriantharid from the Mediterranean Sea near Napoli, Italy. (1) Overview of a ceriantharid tube fragment from the late Eocene Makah Formation (NRM Cn 76105). (2) Overview of the tube fragment from the middle to late Eocene Hoko River Formation (UWBMIP 106332). (3) Close-up on the surface structure showing the ‘knitted pattern’ (NRM Cn 76105). (4, 5) Cerianthus membranaceus (NRM Zool. coll. No. 137355); view of the whole specimen, photographed in alcohol (4), and close-up on its surface structure (5). (6) Close-up of the surface structure of the middle to late Eocene tube from the Hoko River Formation (UWBMIP 106332).

Figure 1

Figure 2. Eocene and Oligocene ceriantharian tubes from the Makah and Lincoln Creek formations in Washington State, USA. (1) Overview of part of the tube from the late Oligocene Lincoln Creek Formation (UWBMIP 117997); arrow indicates partially folded and collapsed area. (2–4) Ceriantharid tube fragments from the late Eocene Makah Formation (NRM Cn 76105) with associated benthic foraminiferans (probably Pullenia bulloides; marked by arrows); overview of specimen with foraminiferans along the outside of the tube (2), and close-ups of areas of the fossil tubes with benthic foraminiferans embedded in the tube (3, 4).