A evolução heterocrônica explica o novo formato corporal de um celacanto do Triássico da Suiça

sexta-feira, novembro 17, 2017

Heterochronic evolution explains novel body shape in a Triassic coelacanth from Switzerland

Lionel Cavin, Bastien Mennecart, Christian Obrist, Loïc Costeur & Heinz Furrer

Scientific Reports 7, Article number: 13695 (2017)


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Embryonic induction Evolution Ichthyology Palaeontology

Received: 05 June 2017 Accepted: 02 October 2017

Published online: 20 October 2017



Phylogenetic relationships of Foreyia maxkuhni gen. et sp. nov. and developmental origin of the derived characters.

Abstract

A bizarre latimeriid coelacanth fish from the Middle Triassic of Switzerland shows skeletal features deviating from the uniform anatomy of coelacanths. The new form is closely related to a modern-looking coelacanth found in the same locality and differences between both are attributed to heterochronic evolution. Most of the modified osteological structures in the new coelacanth have their developmental origin in the skull/trunk interface region in the embryo. Change in the expression of developmental patterning genes, specifically the Pax1/9 genes, may explain a rapid evolution at the origin of the new coelacanth. This species broadens the morphological disparity range within the lineage of these ‘living fossils’ and exemplifies a case of rapid heterochronic evolution likely trigged by minor changes in gene expression.

Acknowledgements

The Palaeontological Institute and Museum, University of Zürich (PIMUZ) enabled H.F. to conduct systematic prospecting and numerous excavations near Davos. The government of Canton Graubünden, the municipality of Davos, and the Bündner Naturmuseum in Chur gave permission for the excavations and financial support. Max Kuhn (Uster) provided generous financial support for the preparation of the specimens by C.O. B.M. and L.Ca. also thank the Département de la culture et du sport de la Ville de Genève for a financial support for computer facilities, and Philippe Wagneur (Natural History Museum of Geneva) for assistance to produce the CT scan movie. We thank Anne Kemp (Griffith University) and Mélanie Debiais-Thibaud (University of Montpellier) for discussion. This paper is a contribution to the project “Evolutionary pace in the coelacanth clade: New evidence from the Triassic of Switzerland” supported by the Swiss National Science Foundation (200021-172700) by L.Ca.

Author information

Affiliations

Department of Geology and Palaeontology, Muséum d’Histoire Naturelle, CP6434, 1211, Geneva, 6, Switzerland

Lionel Cavin

Naturhistorisches Museum Basel, Augustinergasse 2, 4001, Basel, Switzerland

Bastien Mennecart & Loïc Costeur

Erliackerweg 8, 4462, Rickenbach, BL, Switzerland

Christian Obrist

Paläontologisches Institut und Museum der Universität Zürich, Karl Schmid-Strasse 4, 8006, Zurich, Switzerland

Heinz Furrer

Contributions

L.Ca. wrote the description of the new taxon, collected and analyzed the phylogenetic and ontogenetic data, and wrote the corresponding parts of the manuscript. C.O. collected specimens PIMUZ A/I 4620 and PIMUZ A/I 4372, and prepared them. H.F. analyzed the stratigraphic data in the field, and wrote the corresponding methods and results. B.M. and L.Co. performed the CT scan analysis and interpreted the images. L.Ca. and H.F. obtained funding for fieldwork and data analysis. All authors contributed to write the last version of the text.

Competing Interests

The authors declare that they have no competing interests.

Corresponding author

Correspondence to Lionel Cavin.