Aaron M. Bauer

Erosion of lizard diversity by climate change and altered thermal niches

Demise of the Lizards Despite pessimistic forecasts from recent studies examining the effects of global climate change on species, and observed extinctions in local geographic areas, there is little evidence so far of global-scale extinctions. Sinervo et al. (p. 894; see the Perspective by Huey et al.) find that extinctions resulting from climate change are currently reducing global lizard diversity. Climate records during the past century were synthesized with detailed surveys of Mexican species at 200 sites over the past 30 years. Temperature change has been so rapid in this region that rates of adaptation have not kept pace with climate change. The models were then extended to all families of lizards at >1000 sites across the globe, and suggest that climate change-induced extinctions are currently affecting worldwide lizard assemblages. A historical record of lizard populations in Mexico is used to parameterize models that predict global effects of climate change. It is predicted that climate change will cause species extinctions and distributional shifts in coming decades, but data to validate these predictions are relatively scarce. Here, we compare recent and historical surveys for 48 Mexican lizard species at 200 sites. Since 1975, 12% of local populations have gone extinct. We verified physiological models of extinction risk with observed local extinctions and extended projections worldwide. Since 1975, we estimate that 4% of local populations have gone extinct worldwide, but by 2080 local extinctions are projected to reach 39% worldwide, and species extinctions may reach 20%. Global extinction projections were validated with local extinctions observed from 1975 to 2009 for regional biotas on four other continents, suggesting that lizards have already crossed a threshold for extinctions caused by climate change.

Field guide to snakes and other reptiles of Southern Africa

This edition supplements the 397 South African reptiles originally represented in this field guide by 64 new species. Some of these are new discoveries in the region, others are reclassifications. Author Bill Branch has also adapted the original text, modifying distributions and biology to reflect the most up-to-date research on the subject. The book covers 133 species of snake, as well as many and varied lizard and gecko species, tortoises, turtles, terrapins and the crocodile. New species entries introduce 13 gecko species, eight skinks and three snakes, amongst others. Each species entry includes size range, a physical description of the creature and a discussion on biology and breeding, habitat and range. Where subspecies occur, these are described. Each account is accompanied by a distribution map, which has been updated where necessary. Explanatory notes and a comprehensive glossary make the subject accessible to even the beginner herpretologist.

Genome 10K: A Proposal to Obtain Whole-Genome Sequence for 10 000 Vertebrate Species

The human genome project has been recently complemented by whole-genome assessment sequence of 32 mammals and 24 nonmammalian vertebrate species suitable for comparative genomic analyses. Here we anticipate a precipitous drop in costs and increase in sequencing efficiency, with concomitant development of improved annotation technology and, therefore, propose to create a collection of tissue and DNA specimens for 10,000 vertebrate species specifically designated for whole-genome sequencing in the very near future. For this purpose, we, the Genome 10K Community of Scientists (G10KCOS), will assemble and allocate a biospecimen collection of some 16,203 representative vertebrate species spanning evolutionary diversity across living mammals, birds, nonavian reptiles, amphibians, and fishes (ca. 60,000 living species). In this proposal, we present precise counts for these 16,203 individual species with specimens presently tagged and stipulated for DNA sequencing by the G10KCOS. DNA sequencing has ushered in a new era of investigation in the biological sciences, allowing us to embark for the first time on a truly comprehensive study of vertebrate evolution, the results of which will touch nearly every aspect of vertebrate biological enquiry.

Phylogenetic relationships and limb loss in sub-Saharan African scincine lizards (Squamata: Scincidae)

Skinks are the largest family of lizards and are found worldwide in a diversity of habitats. One of the larger and more poorly studied groups of skinks includes members of the subfamily Scincinae distributed in sub-Saharan Africa. Sub-Saharan African scincines are one of the many groups of lizards that show limb reduction and loss, and the genus Scelotes offers an excellent opportunity to look at limb loss in a phylogenetic context. Phylogenetic relationships were reconstructed for a total of 52 taxa representing all subfamilies of skinks as well as other Autarchoglossan families using sequence from six gene regions including; 12S, 16S, and cytochrome b (mitochondrial), as well as alpha-Enolase, 18S, and C-mos (nuclear). The family Scincidae is recovered as monophyletic and is the sister taxon to a (Cordylidae+Xantusiidae) clade. Within skinks the subfamily Acontinae is monophyletic and sister group to all remaining skinks. There is no support for the monophyly of the subfamilies Lygosominae and Scincinae, but sub-Saharan African scincines+Feylinia form a well supported monophyletic group. The monophyly of Scelotes is confirmed, and support is found for two geographic groups within the genus. Reconstructions of ancestral states for limb and digital characters show limited support for the reversal or gain of both digits and limbs, but conservative interpretation of the results suggest that limb loss is common, occurring multiple times throughout evolutionary history, and is most likely not reversible.

Coming to America: multiple origins of New World geckos

Geckos in the Western Hemisphere provide an excellent model to study faunal assembly at a continental scale. We generated a time‐calibrated phylogeny, including exemplars of all New World gecko genera, to produce a biogeographical scenario for the New World geckos. Patterns of New World gecko origins are consistent with almost every biogeographical scenario utilized by a terrestrial vertebrate with different New World lineages showing evidence of vicariance, dispersal via temporary land bridge, overseas dispersal or anthropogenic introductions. We also recovered a strong relationship between clade age and species diversity, with older New World lineages having more species than more recently arrived lineages. Our data provide the first phylogenetic hypothesis for all New World geckos and highlight the intricate origins and ongoing organization of continental faunas. The phylogenetic and biogeographical hypotheses presented here provide an historical framework to further pursue research on the diversification and assembly of the New World herpetofauna.

Repeated Origin and Loss of Adhesive Toepads in Geckos

Geckos are well known for their extraordinary clinging abilities and many species easily scale vertical or even inverted surfaces. This ability is enabled by a complex digital adhesive mechanism (adhesive toepads) that employs van der Waals based adhesion, augmented by frictional forces. Numerous morphological traits and behaviors have evolved to facilitate deployment of the adhesive mechanism, maximize adhesive force and enable release from the substrate. The complex digital morphologies that result allow geckos to interact with their environment in a novel fashion quite differently from most other lizards. Details of toepad morphology suggest multiple gains and losses of the adhesive mechanism, but lack of a comprehensive phylogeny has hindered efforts to determine how frequently adhesive toepads have been gained and lost. Here we present a multigene phylogeny of geckos, including 107 of 118 recognized genera, and determine that adhesive toepads have been gained and lost multiple times, and remarkably, with approximately equal frequency. The most likely hypothesis suggests that adhesive toepads evolved 11 times and were lost nine times. The overall external morphology of the toepad is strikingly similar in many lineages in which it is independently derived, but lineage-specific differences are evident, particularly regarding internal anatomy, with unique morphological patterns defining each independent derivation.

Out of the blue: a novel, trans‐Atlantic clade of geckos (Gekkota, Squamata)

Phylogenetic relationships among gekkotan lizards were estimated from five nuclear protein‐coding genes in separate and combined analyses using maximum parsimony, maximum likelihood and Bayesian analyses. All analyses recovered a monophyletic trans‐Atlantic gecko clade (Phyllodactylidae) consisting of the genera Asaccus, Haemodracon, Homonota, Phyllodactylus, Phyllopezus, Ptyodactylus, Tarentola and Thecadactylus. No other phylogenetic or taxonomic hypotheses have proposed linking these genera, which have been consistently grouped with other taxa outside of the clade. In this paper, we determine the relationships of this new clade to other major gekkotan groups, evaluate previous phylogenetic hypotheses regarding constituent members of this novel clade, and critically examine the use of historically important morphological characters in gekkotan systematics as they relate to this novel clade, specifically — phalangeal formulae, hyoid morphology and external structure of the toe‐pads.

Between a rock and a hard polytomy: Rapid radiation in the rupicolous girdled lizards (Squamata: Cordylidae)

Girdled lizards (Cordylidae) are sub-Saharan Africas only endemic squamate family and contain 80 nominal taxa, traditionally divided into four genera: Cordylus, Pseudocordylus, Chamaesaura and Platysaurus. Previous phylogenetic analysis revealed Chamaesaura and Pseudocordylus to be nested within Cordylus, and the former genera were sunk into the later. This taxonomic revision has received limited support due to the studys poor taxon sampling, weakly supported results and possible temporary nomenclatural instability. Our study analyzes three nuclear and three mitochondrial genes from 111 specimens, representing 51 in-group taxa. Parsimony, likelihood and Bayesian analyses of concatenated and partitioned datasets consistently recovered a comb-like tree with 10, well-supported, monophyletic lineages. Our taxonomic reassessment divides the family into 10 genera, corresponding to these well-supported lineages. Short internodes and low support between the non-platysaur lineages are consistent with a rapid radiation event at the base of the viviparous cordylids.

Global Taxonomic Diversity of Living Reptiles

Reptiles are one of the most ecologically and evolutionarily remarkable groups of living organisms, having successfully colonized most of the planet, including the oceans and some of the harshest and more environmentally unstable ecosystems on earth. Here, based on a complete dataset of all the world’s diversity of living reptiles, we analyse lineage taxonomic richness both within and among clades, at different levels of the phylogenetic hierarchy. We also analyse the historical tendencies in the descriptions of new reptile species from Linnaeus to March 2012. Although (non-avian) reptiles are the second most species-rich group of amniotes after birds, most of their diversity (96.3%) is concentrated in squamates (59% lizards, 35% snakes, and 2% amphisbaenians). In strong contrast, turtles (3.4%), crocodilians (0.3%), and tuataras (0.01%) are far less diverse. In terms of species discoveries, most turtles and crocodilians were described early, while descriptions of lizards, snakes and amphisbaenians are multimodal with respect to time. Lizard descriptions, in particular, have reached unprecedented levels during the last decade. Finally, despite such remarkably asymmetric distributions of reptile taxonomic diversity among groups, we found that the distributions of lineage richness are consistently right-skewed, with most clades (monophyletic families and genera) containing few lineages (monophyletic genera and species, respectively), while only a few have radiated greatly (notably the families Colubridae and Scincidae, and the lizard genera Anolis and Liolaemus). Therefore, such consistency in the frequency distribution of richness among clades and among phylogenetic levels suggests that the nature of reptile biodiversity is fundamentally fractal (i.e., it is scale invariant). We then compared current reptile diversity with the global reptile diversity and taxonomy known in 1980. Despite substantial differences in the taxonomies (relative to 2012), the patterns of lineage richness remain qualitatively identical, hence reinforcing our conclusions about the fractal nature of reptile biodiversity.

Availability of new Bayesian-delimited gecko names and the importance of character-based species descriptions

Leache & Fujita [[1][1]] present an empirical example of Bayesian species delimitation (BSD; [[2][2]]) to recognize three new species of African geckos from within the range of the widespread taxon Hemidactylus fasciatus , Gray 1842. As with any new method, BSD will undoubtedly generate questions