A phylogenomic analysis of tropidurid lizards (Squamata, Tropiduridae): unprecedented relationships require a novel systematic classification

Tropidurine research has never been in a better place. Nevertheless, conflicting results concerning the monophyly of Tropidurus and the number of undescribed tropidurine species have posed the need for a comprehensive assessment of both the phylogenetic relationships and taxonomic diversity in this group. This study reviews the current status of tropidurine systematics and propose a new taxonomy consistent with the hypothesized relationships. Our molecular analyses were based on thousands of ultra-conserved elements (UCEs) and included representatives from all tropidurine genera plus selected outgroups. Our results revealed a monophyletic Tropidurinae and, in great part, unprecedented relationships among tropidurine clades. Among our most relevant phylogenetic results: Uranoscodon was confirmed as the sister of all remaining tropidurines; Tropidurus was revealed paraphyletic with respect to Eurolophosaurus, Plica, Strobilurus, and Uracentron; T. bogerti was placed as closely related to Uracentron; Strobilurus was recovered as the sister group of the T. spinulosus group, and Eurolophosaurus appeared as sister of the T. torquatus plus the T. semitaeniatus species groups. To rectify the paraphyly of Tropidurus, two new genera must be erected to accommodate, respectively, the T. spinulosus and the T. bogerti species groups; Tapinurus Amaral, 1933 must be resurrected for the T. semitaeniatus species group; and Tropidurus Wied, 1825 must be restricted to the T. torquatus species group. Our new classification recognizes ten genera, 67 species, and 12 subspecies. However, recovered relationships point out the existence of a number of candidate species whose formal taxonomic description imply the redelimitation of several nominal taxa provisionally regarded as valid.