A global analysis of viviparity in squamates highlights its prevalence in cold climates

ZIMIN, ANNA; ZIMIN, SEAN V.; SHINE, RICHARD; AVILA, LUCIANO; BAUER, AARON; BÖHM, MONIKA; BROWN, RAFE; BARKI, GONI; DE OLIVEIRA CAETANO, GABRIEL HENRIQUE; CASTRO HERRERA, FERNANDO; CHAPPLE, DAVID G.; CHIRIO, LAURENT; COLLI, GUARINO R.; DOAN, TIFFANY M.; GLAW, FRANK; GRISMER, L. LEE; ITESCU, YUVAL; KRAUS, FRED; LEBRETON, MATTHEW; MARTINS, MARCIO; MORANDO, MARIANA; MURALI, GOPAL; NAGY, ZOLTÁN T.; NOVOSOLOV, MARIA; OLIVER, PAUL; PASSOS, PAULO; PAUWELS, OLIVIER S. G.; PINCHEIRA?DONOSO, DANIEL; RIBEIRO?JUNIOR, MARCO ANTONIO; SHEA, GLENN; TINGLEY, REID; TORRES?CARVAJAL, OMAR; TRAPE, JEAN?FRANÇOIS; UETZ, PETER; WAGNER, PHILIPP; ROLL, URI; MEIRI, SHAI

Global Ecology and Biogeography

WILEY-BLACKWELL PUBLISHING, INC

Año: 2022 vol. 2022 p. 1 - 16

1466-822X

Aim: Viviparity has evolved more times in squamates than in any other vertebrategroup; therefore, squamates offer an excellent model system in which to study thepatterns, drivers and implications of reproductive mode evolution. Based on currentspecies distributions, we examined three selective forces hypothesized to drive theevolution of squamate viviparity (cold climate, variable climate and hypoxic conditions) and tested whether viviparity is associated with larger body size.Location: Global.Time period: Present day.Taxon: Squamata.Methods: We compiled a dataset of 9061 squamate species, including their distributions, elevation, climate, body mass and reproductive modes. We applied species-leveland assemblage-level approaches for predicting reproductive mode, both globally andwithin biogeographical realms. We tested the relationships of temperature, interannual and intra-annual climatic variation, elevation (as a proxy for hypoxic conditions)and body mass with reproductive mode, using path analyses to account for correlations among the environmental predictors.Results: Viviparity was strongly associated with cold climates at both species and assemblage levels, despite the prevalence of viviparity in some warm climates. Viviparitywas not clearly correlated with climatic variability or elevation. The probability ofbeing viviparous exhibited a weak positive correlation with body size.Conclusions: Although phylogenetic history is important, potentially explaining theoccurrence of viviparous species in regions that are warm at present, current globalsquamate distribution is characterized by a higher relative abundance of viviparityin cold environments, supporting the prediction of the “cold-climate” hypothesis.The roles of climatic variation and hypoxia are less important and not straightforward. Elevation probably exerts various selective pressures and influences the prevalence of viviparity primarily through its effect on temperature rather than on oxygenconcentration.