The skull of the semi-aquatic neotropical lizard Echinosaura horrida (Gymnophthalmidae: Cercosaurinae) reveals new synapomorphies within Gymnophthalmoidea.

The rough teiid or water cork lizard (Echinosaura horrida) is a small reptile from Colombia and Ecuador placed in a genus that contains eight species and well-known phylogenetic relationships. Here we provide a detailed description and illustrations, bone by bone, of its skull, while we discussed its intraspecific variation by comparing high-resolution computed tomography data from two specimens and the variation within the genus by including previously published data from Echinosaura fischerorum. This allowed to propose putative diagnostic character states for Echinosaura horrida and synapomorphies for Echinosaura. In addition, our discussion includes broader comparisons of new character transformations of the jugal, vomer, orbitosphenoid, and hyoid. These characters are important for diagnosing clades at different levels of the Gymnophthalmoidea phylogeny.

Comparative anatomy and evolution of the atlantoaxial complex in the fossorial lineage Amphisbaenia (Squamata: Lacertoidea).

The atlas and axis are the first two vertebrae from the cervical series; these two vertebrae are responsible for neck flexion, extension, and rotation movements, while providing insertion points for muscles and tendons. Amphisbaenia is a group of fossorial squamates known for having four distinctive head shapes, which are related to different excavation methods. However, little is known about the relationship between these different digging patterns and the anatomy and evolution of the atlantoaxial complex. In this study, we used computed microtomography data to describe in detail of the atlantoaxial complex for 15 species, belonging to all six current families of Amphisbaenia. Furthermore, we evaluate evolutionary scenarios of selected characters related to the atlantoaxial complex in the most recent phylogeny for Amphisbaenia, using the criteria of parsimony and maximum likelihood. Our results indicate that the evolutionary pattern of the atlantoaxial complex presents a diversification in its morphology that is not always correlated with the shape of the head. This analysis reinforces the hypothesis of remarkable morphological convergences in the evolutionary history of Amphisbaenia. Additionally, some of the characters studied may represent independent evolution through convergence in some cases (e.g., horizontal axis of the neural column) and parallelism in others (e.g., present or absent from the transverse process).

A species-level total evidence phylogeny of the microteiid lizard family Alopoglossidae (Squamata: Gymnophthalmoidea).

Alopoglossidae is a family of Neotropical lizards composed of 23 species allocated in two genera (Alopoglossus and Ptychoglossus). There is a lack of knowledge about the phylogenetic relationships and systematics of this family. Published phylogenies that include alopoglossid species have very low taxon coverage within the family, and are usually based on limited character sampling. Considering these shortcomings, we infer the phylogenetic relationships of Alopoglossidae-including all but one species in the family-based on the combined analyses of DNA sequences and morphological characters. We use four loci (the mitochondrial 12S, 16S and ND4; the nuclear C-mos) and a matrix of 143 phenotypic characters from scutellation, tongue morphology, hemipenis morphology, and osteology. The dataset is analyzed with Maximum Parsimony, with four alternative weighting schemes: three under Extended Implied Weighting, and one with equal weighting. The respective resulting topologies are compared in a sensitivity analysis framework. Our analyses support the paraphyly of Ptychoglossus, with Alopoglossus nested within it. We provide an updated classification for the family, where Ptychoglossus Boulenger, 1890 is considered a junior synonym of Alopoglossus Boulenger, 1885.

Skull Morphology of the Lizard Ptychoglossus vallensis (Squamata: Alopoglossidae) With Comments on the Variation Within Gymnophthalmoidea.

In recent years, major changes have been proposed for the phylogenetic relationships within the Gymnophthalmoidea, including the description of Alopoglossidae. Recent studies relied primarily on molecular data and have not accounted for evidence from alternative sources, such as morphology. In this study, we provide a detailed bone-by-bone description of the skull of Ptychoglossus vallensis and compare this species with other gymnophthalmoideans. The description was based on 10 cleared-and-stained specimens, four disarticulated skulls, and computed microtomography data of P. vallensis. Most recent phylogenetic hypothesis for the Gymnophthalmoidea was used as a framework to compare the skull of P. vallensis with other species of the Alopoglossidae, Gymnophthalmidae, and Teiidae. Marked similarities between alopoglossids and gymnophthalmids were observed in contrast to teiids, probably due to convergence generated by miniaturization. We also qualitatively analyzed the kinesis of the skull of P. vallensis concluding that is highly akinetic, a trait commonly evolved in fossorial, primarily burrowing squamates. We also describe one unique osteological feature for Alopoglossidae that is not known in any other squamate group. Anat Rec, 302:1074-1092, 2019. © 2018 Wiley Periodicals, Inc.