The first record of anguine lizards (Anguimorpha, Anguidae) from the early Miocene locality Ulm – Westtangente in Germany

<p>The first fossil anguine material from the lower Miocene (MN 2) locality Ulm – Westtangente in Germany is described. The parietal and compound bone of the lower jaw can be attributed to <i>Ophisaurus holeci</i>, previously known only from younger age (MN 3–MN 7). Moreover, the parietal represents the largest parietal of this species. In other disarticulated material, such as frontal, maxilla, dentary and osteoderms, alpha taxonomy is not possible and these elements cannot be allocated at the species level. Despite a limited data source, a phylogenetic analysis was done (16 taxa, 36 characters) producing four equally parsimonious trees. The analysis shows a close relationship of <i>O. holeci</i> and the Eocene <i>Ophisauriscus quadrupes</i>. These two taxa form a monophyletic clade, a sister-clade to <i>Ophisaurus</i> + <i>Anguis</i>. However, more complete skeletal material of <i>O. holeci</i> is needed to support such a statement. We used our phylogenetic analysis to analyze trace character history for one frontal and three parietal characters. The palaeoenvironmental conditions of the locality Ulm – Westtangente bring further support of the previous hypothesis that <i>O. holeci</i> was adapted to environments with high ground water levels – environments around lakes or rivers.</p

<i>Coelostegus prothales</i> Carroll and Baird, 1972.

We redescribe the holotype and only known specimen of the early eureptile Coelostegus prothales from the Upper Carboniferous of the Czech Republic using photogrammetric scanning and a virtual 3D rendition of its skull. New information is available on several skull and lower jaw bones, including the postorbital, supratemporal, tabular, postparietal, angular, and prearticular. The new data also permit the correct identification of previously undetected or mis-identified elements (e.g., supratemporal; quadratojugal; angular). We provide an amended diagnosis of Coelostegus and a new reconstruction of the skull in dorsal and lateral views. To evaluate the affinities of Coelostegus, we code this taxon in two recently published taxon-character matrices. Parsimony and Bayesian analyses do not permit firm conclusions on the phylogenetic position of Coelostegus or, indeed, the status and extrinsic relationships of protorothyridid amniotes. Coelostegus emerges either as the sister taxon to the recently redefined Diapsida (Araeoscelidia; Varanopidae; Parareptilia; Neodiapsida), as one of the most basal protorothyridids, or as a derived stem-group amniote in various parsimony-based analyses, or as the basalmost protorothyridid in one Bayesian analysis, with protorothyridids forming a paraphyletic array relative to Diapsida. We review the cranial similarities and differences between Coelostegus and other protorothyridid genera and discuss the implications that various phylogenetic results have for our understanding of early amniote relationships.</div

<i>Coelostegus prothales</i> Carroll and Baird, 1972.

A. Drawing of the postcranial skeleton. B. Photograph of ventral scales.</p

<i>Coelostegus prothales</i> Carroll and Baird, 1972.

Virtual 3D model of the posterior portion of the skull showing the check bones relative to skull-table elements as preserved (A) and with colour-coded individual bones (B). In B, the shape of the supratemporal is reconstructed.</p

Interrelationships of <i>Coelostegus prothales</i>.

Bootstrap 50% majority-rule consensus from Ford and Benson’s [7] dataset, with bootstrap percentage support appended to branches. (TIF)</p

Ford and Benson’s [7] dataset for Bayesian analysis.

MrBayes-readable script for running non-calibrated Bayesian analysis after inclusion of Coelostegus. (TXT)</p

<i>Coelostegus prothales</i> Carroll and Baird, 1972.

Virtual 3D model of the skull as preserved (A) and with colour-coded individual bones (B).</p

<i>Coelostegus prothales</i> Carroll and Baird, 1972.

Reconstruction of the skull in dorsal (A) and left lateral (B) views alongside colour-coded and labelled skull diagrams (C, D).</p

Results of Bayesian analysis.

Output of MrBayes analysis of Ford and Benson’s [7] dataset (see S3 Appendix). (RTF)</p

Interrelationships of <i>Coelostegus prothales</i>.

Jackknife 50% majority-rule consensus from Simoes et al.’s [8] dataset, with jackknife percentage support appended to branches. (TIF)</p