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

Abstract

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 Ophisaurus holeci, 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 O. holeci and the Eocene Ophisauriscus quadrupes. These two taxa form a monophyletic clade, a sister-clade to Ophisaurus + Anguis. However, more complete skeletal material of O. holeci 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 O. holeci was adapted to environments with high ground water levels – environments around lakes or rivers.