A new specimen of Puppigerus from the London Clay of Walton on the Naze, Essex, United Kingdom and the speciation and palaeo-distribution of marine turtles during the Eocene
- Published
- Accepted
- Subject Areas
- Paleontology
- Keywords
- Eocene, Ypresian, Lutetian, Vertebrates, Marine turtles, Cheloniidae, Toxochelyidae, Paleogeography, Taxonomy, CT scans
- Copyright
- © 2015 Moody et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
- Cite this article
- 2015. A new specimen of Puppigerus from the London Clay of Walton on the Naze, Essex, United Kingdom and the speciation and palaeo-distribution of marine turtles during the Eocene. PeerJ PrePrints 3:e892v1 https://doi.org/10.7287/peerj.preprints.892v1
Abstract
Background. A well preserved skull reported from the London Clay of the Walton on the Naze in Essex, UK adds an additional record to a rich turtle assemblage from the Eocene (Ypresian-Lutetian) of several depositional basins across NW Europe and North Africa including the London and Belgian Basins. The London Clay and age equivalent formations are dated as c.50 million years by the analysis of the microfossils, vertebrates, volcanic ash beds found throughout the sequence. The London Clay in the area of Walton on the Naze, Essex is comprised of fine grained, clay-rich deposits that yield a host of invertebrates, fossil plant debris, including seeds, together with mostly disarticulated skeletons of fish, birds, mammals and reptiles; the better specimens being enclosed in septarian nodules. The biostratigraphy of the various levels is confirmed by Chistopher King (deceased). Methods. In 1977 a fossil rich calcareous nodule was presented to the NHM, London, UK and the preparatory work was undertaken the same year by Ron Croucher of the former NHM, Palaeontology Conservation Unit and produced a complete 3 dimensional skull and lower jaw, complete limb and girdle material plus hyoid bones and numerous vertebrae and the incomplete presentation of a small delicate shell. Several years elapsed before the specimen was ready for study but its research potential has only recently been recognised. Results. The published discoveries of primitive cheloniids in Russia and North Africa have provided evidence for the global distribution of the cheloniids. The shell material seemingly belongs to a juvenile whereas the skull is comparable to the largest specimens of either Puppigerus or Argillochelys found in the London Clay of the Isle of Sheppey, Kent, UK or the Eocene sediments of the Belgian Basin. The excellent preservation of this ‘Walton’ skull (NHMUK R14375) enables the authors to draw comparisons with the exceptional material housed in The Institut Royal des Sciences Naturelles in Bruxelles. A detailed description of the skull NHMUK R1437 will be presented. Discussion. In an earlier study Moody (1974) examined an endocranial cast taken from the skull of Puppigerus camperi (IRSNB. IG 8402) that showed the principal flexures of the brain and so to extend this study we include an analysis of recent CT scans of several skulls of Puppigerus and Argillochelys. The cranial characteristics are almost identical to the skull of the Moroccan specimen described by Tong et al 2012 but there is a definitive lack of the ‘spatulate’ palatines found in Puppigerus camperi. The development of the spatulate palatine is found in both juvenile and adult specimens of P. camperi whereas flatter less developed palatines are characteristic throughout the growth cycle in other species.
Author Comment
This is an abstract which has been accepted for the 5th Turtle Evolution Symposium.
