Sex determination systems in reptiles are related to ambient temperature but not to the level of climatic fluctuation.

"the resulting shapefiles for 85 reptile species are available in the figshare platform at the following link https://figshare com/s/83d59b0d26f8df636621 .; generated shapefiles for 85 reptile species are available in the figshare platform at https://figshare com/articles/reptile_shapefiles/7416638 . the r package used to combine the climate data and the species shapefiles is available at https://github com/annakrystalli/iucnextractr ."

"the r package used in the study is available at https://github com/annakrystalli/iucnextractr .; the r package used to combine the climate data and the species shapefiles is available at https://github com/annakrystalli/iucnextractr .; the r package used for the ecological niche modeling routines is available at https://github com/marlonecobos/kuenm ."

"Competing interests The authors declare that they have no competing interests."

"Funding This research was supported by a Frontiers in Science CONACYT grant (No. FC-2016 /1682) and a Royal Society Newton Advanced Fellowship (no. NA160564) to DC, TS, and AOU for data collection, data generation, and data analyses; a NKFIH-2558-1/2015 and ÉLVONAL-KKP 126949 to TS for data collection; a NERC grant (NE/P004121/1), a Royal Society Dorothy Hodgkin Research Fellowship (DH071902) and a CONACyT-AMC-Royal Society Newton mobility grant to AOU for students’ and researchers’ mobility; travel grants SEP-UNAM-FUNAM Programa de Capacitación en Métodos de Investigación/2016 to PCP and CRS and a special grant from the Undergraduate Programme on Genomic Sciences – UNAM to PCP for students’ mobility."