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New Silurian and Devonian fork-tailed 'thelodonts' are jawless vertebrates with stomachs and deep bodies

Nature volume 361, pages 442–444 (1993)Cite this article

Abstract

ALL agnathans (jawless vertebrates) are generally considered to have lacked a stomach, as do the living lampreys. Thelodonts are agnathans of Silurian and Devonian age whose bodies were covered by tiny, hollow, tooth-like scales which are useful for correlating rocks. We have discovered a new group of agnathans with 'thelodont' scales but with a body plan very different from that of previously known thelodonts. Sediment infillings reveal gut morphology that includes a probable stomach, suggesting that stomachs arose before jaws in vertebrate evolution. These new fork-tailed 'thelodonts9 are also the first agnathans known to have deep, compressed bodies. They represent an important new clade of early vertebrates and are potential close relatives of gnathostomes (jawed vertebrates).

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Author notes

  1. Michael W. Caldwell

    Present address: Redpath Museum, McGill University, 859 Sherbrooke Street W., Montréal, Québec, H3A 2K6, Canada

Authors and Affiliations

  1. Department of Zoology and Laboratory for Vertebrate Paleontology, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada

    Mark V. H. Wilson & Michael W. Caldwell

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  1. Mark V. H. Wilson
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  2. Michael W. Caldwell
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Wilson, M., Caldwell, M. New Silurian and Devonian fork-tailed 'thelodonts' are jawless vertebrates with stomachs and deep bodies. Nature 361, 442–444 (1993). https://doi.org/10.1038/361442a0

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