Abstract
Several extinct species are known from the family Lacertidae, but due to poor preservation, many of them are based on single bones. Here, we compare phylogenetic signals of disarticulated premaxillae, maxillae and dentaries of lacertids from four French Oligocene localities (Coderet, La Colombière, Roqueprune 2, Mas de Got B). We identified five morphotypes among the premaxillae, six among the maxillae, and ten among the dentaries. These morphotypes were scored as individual taxa per locality into three separate character matrices with the same 246 characters, one matrix for each jaw element. Subsequently, the phylogenetic position of the morphotypes was tested using maximum parsimony. The consensus trees with the dentaries and the maxillae found a large polytomy including all taxa except the outgroup taxon Gekko gecko. The consensus tree with the premaxillae showed a considerably more resolved topology but found all morphotype taxa outside Lacertidae. In a second step, we compared the constitution of our three datasets and the morphotype taxa. Our results suggest that a combination of convergent characters and missing data led to the outgroup position of the premaxilla morphotype taxa. The poor resolution of the maxillae strict consensus is likely a consequence of their fragmentary preservation. For the dentaries, a high amount of missing data due to the high number of morphotype taxa most likely caused the poor tree resolution. Indeed, tests with fewer morphotypes found tree resolutions comparable to the premaxilla data. When linking the morphotypes, five possible lacertid "species" were found. Comparison with already known French Oligocene lacertid species points to a slightly higher species richness of Lacertidae at that time than known before. Reliable species classification based on phylogeny only seems possible when combining the jaw elements or in association with other cranial and postcranial material, putting some doubt on species identifications based on single bones.
Highlights
The family Lacertidae constitutes the taxonomically dominant reptile group in Europe (Arnold et al, 2007; Sillero et al, 2014; Speybroeck et al, 2016; Villa and Delfino, 2019a; Speybroeck et al, 2020)
Wencker et al / Cladistics 0 (2021) 1–38 crown-group lacertids are thought to have originated in Europe, based on the fact that fossils considered to be close to or at the base of the crown group were found on this continent (Borsuk-Bialynicka et al, 1999; C ernansky and Auge, 2013)
Podarcis siculus Podarcis hispanicus Podarcis tiliguerta Podarcis muralis Podarcis waglerianus Lacerta viridis Lacerta trilineata Lacerta bilineata Lacerta strigata Lacerta agilis Lacerta media Lacerta schreiberi Timon princeps Timon kurdistanicus Timon pater Timon lepidus we explore the possible reasons for this issue, and what this could mean for the systematics of extinct lacertids from the Oligocene of France
Summary
The family Lacertidae constitutes the taxonomically dominant reptile group in Europe (Arnold et al, 2007; Sillero et al, 2014; Speybroeck et al, 2016; Villa and Delfino, 2019a; Speybroeck et al, 2020). A recent study found strong morphological similarities between modern Lacertidae and skeletal material from the early Eocene of Mutigny, France (MP 8–9; C ernansky et al, 2020). These studies are further supported by molecular clock analyses yielding estimates for the split between Lacertinae and Gallotiinae during the late Palaeocene (58–56 Ma; Hipsley et al, 2009). Challenges regarding the interpretation of the time of origin of Lacertidae derive from the difficulties in resolving higher-level phylogenetic relationships
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