Climate drives global functional trait variation in lizards

Predicting Conservation Status of Testudoformes under Climate Change Using Habitat Models

Climate change promotes variations in distribution ranges, potentially leading to biodiversity loss and increased extinction risks for species. It is crucial to investigate these variations under future climate change scenarios for effective biodiversity conservation. Here, we studied the future distribution ranges of 268 Testudoformes species under climate change using habitat models, specifically species distribution models (SDMs), to assess their conservation status. Our results have indicated that over half of species are projected to experience declines in their potential distribution ranges under two scenarios. In particular, we found that three critically endangered species-Three-striped roofed turtle (Batagur dhongoka), Durango mud turtle (Kinosternon durangoense), and Colombian mud turtle (Kinosternon dunni)-displayed extraction of their distribution ranges and faced extinction under global climate change. Additionally, our analysis revealed that the potential distribution ranges of some species might increase under future climate scenarios. However, these findings must be interpreted with caution as they do not account for other significant factors such as biological invasions, population structure, land-use change, anthropogenic disturbances, and inter-organism interrelationships. Future studies should incorporate these factors to provide a more comprehensive assessment of extinction risks. Our findings suggest that climate change, in conjunction with habitat degradation and human activities, must be considered when assessing the extinction risks of Testudoformes.

Assessing Reptile Conservation Status under Global Climate Change

Global climate change drives variations in species distribution patterns and affects biodiversity, potentially increasing the risk of species extinction. Investigating the potential distribution range of species under future global climate change is crucial for biodiversity conservation and ecosystem management. In this study, we collected distributional data for 5282 reptile species to assess their conservation status based on distributional ranges using species distribution models. Our predictions indicate that the potential distribution ranges for over half of these species are projected to decrease under different scenarios. Under future scenarios with relatively low carbon emissions, the increase in the number of threatened reptiles is significantly lower, highlighting the importance of human efforts. Surprisingly, we identified some endangered species that are projected to expand their distribution ranges, underscoring the potential positive effects of climate change on some special species. Our findings emphasize the increased extinction risk faced by reptile species due to climate change and highlight the urgent need to mitigate the effects of habitat degradation and human activities on their potential distribution in the future.

Body size estimation from isolated fossil bones reveals deep time evolutionary trends in North American lizards

Lizards play vital roles in extant ecosystems. However, their roles in extinct ecosystems are poorly understood because the fossil record of lizards consists mostly of isolated bones. This makes it difficult to document changes in lizard morphology and body size over time, which is essential for studies of lizard paleoecology and evolution. It is also difficult to compare available fossil lizard data with existing sources of extant lizard data because extant studies rarely measure individual bones. Furthermore, no previous study has regressed measurements of individual bones to body length across crown lizard groups, nor tested those regressions on fossil skeletons. An extensive dataset of individual bone measurements from extant lizards across crown taxonomic groups is here employed to develop novel methods for estimating lizard body size from isolated fossil elements. These methods were applied to a comparably large dataset of fossil lizard specimens from the robust Paleogene record (66-23 Ma) of the Western Interior of North America. This study tests the hypothesis that anatomical proportions have been conserved within higher-level crown lizard groups since the Paleogene and can therefore be used to reconstruct snout-vent length (SVL) and mass for fossil specimens referred to the same groups. Individual bones demonstrated strong correlation with SVL in extant as well as fossil lizard specimens (R2 ≥ 0.69). Equations for mass estimation from individual bones were derived from the SVL regressions using published equations for calculating lizard body mass from SVL. The resulting body size estimates from regression equations for the entire fossil dataset revealed that lizards reached greatest maximum body size in the middle Paleogene, with the largest size class dominated by anguid lizards that exceeded 1 meter in SVL and 1.5 kg in body mass. Maximum body size decreased to under 400 mm and below 1.5 kg in the late Paleogene. No association was found between changes in maximum lizard body size and marine isotope proxies of global temperature through the Paleogene. This is the first study to investigate body size evolution across lizard clades over a deep time interval and for a large geographic region. The proposed methods can be used to generate body size regressions and provide estimates of body size for isolated lizard bones referred to any crown group.