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Article: Cranial osteology of the Middle Jurassic (Callovian) Martillichthys renwickae (Neopterygii, Pachycormiformes) with comments on the evolution and ecology of edentulous pachycormiforms

Papers in Palaeontology - Volume 7 Issue 1 - Cover
Publication: Palaeontology
Volume: 7
Part: 1
Publication Date: Febuary 2021
Page(s): 111 136
Author(s): Claire Dobson, Sam Giles, Zerina Johanson, Jeff Liston, and Matt Friedman
DOI: 10.1002/spp2.1276
Addition Information

How to Cite

DOBSON, C., GILES, S., JOHANSON, Z., LISTON, J., FRIEDMAN, M. 2021. . Papers in Palaeontology, 7, 1, 111-136. DOI: /doi/10.1002/spp2.1276

Author Information

  • Claire Dobson - Department of Earth Sciences University of Oxford Oxford OX1 3AN UK
  • Sam Giles - Department of Earth Sciences University of Oxford Oxford OX1 3AN UK
  • Sam Giles - School of Geography, Earth & Environmental Sciences University of Birmingham Edgbaston B15 2TT UK
  • Zerina Johanson - Department of Earth Sciences The Natural History Museum London SW7 5BD UK
  • Jeff Liston - Department of Natural Sciences National Museum of Scotland Old Town, Chambers Street Edinburgh EH1 1JF UK
  • Jeff Liston - School of Earth Sciences University of Bristol Wills Memorial Building, Queen's Road Bristol BS8 1RJ UK
  • Jeff Liston - Institute of Biodiversity, Animal Health & Comparative Medicine College of Medical, Veterinary & Life Sciences University of Glasgow University Avenue Glasgow G12 8QQ UK
  • Jeff Liston - SNSB Bayerische Staatssammlung für Paläontologie und Geologie Munich Germany
  • Matt Friedman - Department of Earth Sciences University of Oxford Oxford OX1 3AN UK
  • Matt Friedman - Museum of Paleontology & Department of Earth & Environmental Sciences University of Michigan Ann Arbor MI 48109‐1079 USA

Publication History

  • Issue published online: 08 March 2021
  • Manuscript Accepted: 30 January 2019
  • Manuscript Received: 06 September 2018

Funded By

Leverhulme Trust. Grant Number: RPG‐2015-126

Online Version Hosted By

Wiley Online Library
Get Article: Wiley Online Library [Pay-to-View Access] |

Abstract

Our understanding of the ecology and phylogenetic relationships of Pachycormiformes, a group of Mesozoic stem teleosts including the iconic Leedsichthys, has often been hindered by a lack of comprehensive morphological information. Micro‐CT scanning of an articulated, although flattened, cranium of the edentulous Martillichthys renwickae from the Middle Jurassic (Callovian) Oxford Clay of the UK reveals previously unknown internal details of the most complete suspension‐feeding pachycormiform skull known, including the palate, braincase and branchial skeleton. The latter preserves gill rakers with elongate, pointed projections similar to those of Asthenocormus, in contrast to the finer fimbriations associated with Leedsichthys. We also reinterpret some previously described features, including dermal bone patterns of the snout, skull roof and lower jaw, and the morphology of the ventral hyoid arch. These new anatomical data reinforce the phylogenetic placement of Martillichthys as part of the Jurassic clade of edentulous pachycormiforms. The elongate skull geometry of these Jurassic taxa is strikingly similar to that of Ohmdenia, the sister taxon to edentulous pachycormiforms, but contrasts sharply with the morphology of the Late Cretaceous edentulous pachycormiform Bonnerichthys, raising questions over the phylogenetic relationships among these taxa. Most significantly, Martillichthys shows specialized characters with a restricted phylogenetic distribution among suspension‐feeding pachycormiforms, including the distinctive gill rakers and a greatly extended occipital stalk. Our analysis of Martillichthys supports past interpretations of a close relationship with Asthenocormus, and provides a model for interpreting the less complete remains of other members of this enigmatic group of fishes.

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