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Abstract Scincidae is one of the most species-rich and cosmopolitan clades of squamate reptiles. Abundant disarticulated fossil material has also been attributed to this group, however, no complete pre-Cenozoic crown-scincid specimens have been found. A specimen in Burmite (99 MYA) is the first fossil that can be unambiguously referred to this clade. Our analyses place it as nested within extant skinks, supported by the presence of compound osteoderms formed by articulated small ostedermites. The specimen has a combination of dorsal and ventral compound osteoderms and overlapping cycloid scales that is limited to skinks. We propose that this type of osteoderm evolved as a response to an increased overlap of scales, and to reduced stiffness of the dermal armour. Compound osteoderms could be a key innovation that facilitated diversification in this megadiverse family. 

Abstract Liotyphlopsis a genus of blindsnakes distributed in Central and South America. We reviewed specimens ofLiotyphlops albirostrisalong its current distribution range and, based on morphological data and ecological niche modeling analyses, we restrict the geographical range ofL. albirostrisand validate three previously described species. In this revision, we describe the morphological variation in the populations from Panamá, Colombia, Ecuador, and Venezuela, and propose a new taxonomic arrangement. We revalidate three previous synonyms ofL. albirostristo full species status, while dividing the populations from Colombia in two subspecies―one attributed to a previously recognized species from the Caribbean region, and a new one from the Andean region. The new species differs fromL. albirostrisfrom Panamá in cephalic scale arrangements that effectively reduces the previously reported variability of these scales inL. albirostris. We also explore some osteological differences that are congruent with the variation observed. We hope that the recognition of these new species better represents the diversity withinLiotyphlops, helping to bring these new species out of their cryptic status so that they will be considered in future conservation efforts. 

Abstract BackgroundOne goal of evolutionary developmental biology is to understand the role of development in the origin of phenotypic novelty and convergent evolution. Geckos are an ideal system to study this topic, as they are species‐rich and exhibit a suite of diverse morphologies—many of which have independently evolved multiple times within geckos. ResultsWe characterized and discretized the embryonic development ofLepidodactylus lugubris—an all‐female, parthenogenetic gecko species. We also used soft‐tissue μCT to characterize the development of the brain and central nervous system, which is difficult to visualize using traditional microscopy techniques. Additionally, we sequenced and assembled a de novo transcriptome for a late‐stage embryo as a resource for generating future developmental tools. Herein, we describe the derived and conserved patterns ofL. lugubrisdevelopment in the context of squamate evolution and development. ConclusionsThis embryonic staging series, μCT data, and transcriptome together serve as critical enabling resources to study morphological evolution and development, the evolution and development of parthenogenesis, and other questions concerning vertebrate evolution and development in an emerging gecko model. 

ABSTRACT 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 ofPtychoglossus vallensisand compare this species with other gymnophthalmoideans. The description was based on 10 cleared‐and‐stained specimens, four disarticulated skulls, and computed microtomography data ofP. vallensis. Most recent phylogenetic hypothesis for the Gymnophthalmoidea was used as a framework to compare the skull ofP. vallensiswith 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 ofP. vallensisconcluding 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.