Remarkable preservation of brain tissues in an Early Cretaceous iguanodontian dinosaur
Martin D. Brasier1,†, David B. Norman2,*, Alexander G. Liu2,3,*, Laura J. Cotton4, Jamie E. H. Hiscocks5, Russell J. Garwood6,7, Jonathan B. Antcliffe8,9,10 and David Wacey3,11
- Author Affiliations
1Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
2Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
3School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
4School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong SAR, China
5Cantelupe Road, Bexhill-on-Sea, East Sussex TN40 1PP, UK
6School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK
7Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
8Institute of Earth Sciences, University of Lausanne, 1015 Lausanne, Switzerland
9Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
10Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, UK
11Centre for Microscopy Characterisation and Analysis, and Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
- Author Notes
↵† Deceased 16 December 2014.
↵*Correspondence: agscl2@cam.ac.uk; dn102@cam.ac.uk
Abstract
It has become accepted in recent years that the fossil record can preserve labile tissues. We report here the highly detailed mineralization of soft tissues associated with a naturally occurring brain endocast of an iguanodontian dinosaur found in c. 133 Ma fluvial sediments of the Wealden at Bexhill, Sussex, UK. Moulding of the braincase wall and the mineral replacement of the adjacent brain tissues by phosphates and carbonates allowed the direct examination of petrified brain tissues. Scanning electron microscopy (SEM) imaging and computed tomography (CT) scanning revealed preservation of the tough membranes (meninges) that enveloped and supported the brain proper. Collagen strands of the meningeal layers were preserved in collophane. The blood vessels, also preserved in collophane, were either lined by, or infilled with, microcrystalline siderite. The meninges were preserved in the hindbrain region and exhibit structural similarities with those of living archosaurs. Greater definition of the forebrain (cerebrum) than the hindbrain (cerebellar and medullary regions) is consistent with the anatomical and implied behavioural complexity previously described in iguanodontian-grade ornithopods. However, we caution that the observed proximity of probable cortical layers to the braincase walls probably resulted from the settling of brain tissues against the roof of the braincase after inversion of the skull during decay and burial.
Supplementary material:
Information regarding associated fossil material, and additional images, can be found at https://doi.org/10.6084/m9.figshare.c.3519984
Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.
© 2016 The Author(s). Published by The Geological Society of London
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