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Are Bergmann's and Jordan's rules valid for a neotropical pitviper?

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Autor(es):
Servino, L. M. ; Ferrarini, J. M. G. ; Nogueira, C. d. C. ; Barbo, F. E. ; Sawaya, R. J.
Número total de Autores: 5
Tipo de documento: Artigo Científico
Fonte: JOURNAL OF ZOOLOGY; v. 323, n. 4, p. 10-pg., 2024-06-12.
Resumo

Morphological variation along the spatial distribution of species has been extensively investigated in ecological studies, and several ecogeographical rules explore the relationships between morphological traits and the environment. Many morphological traits are correlated, providing an opportunity to evaluate the validity of multiple ecogeographical rules simultaneously. Bergmann's rule predicts that endothermic animals in colder locations are larger than those in warmer locations. Jordan's rule predicts that fish from colder locations have more vertebrae than those from warmer locations. We tested the validity of Bergmann's and Jordan's rules for the neotropical lancehead snake Bothrops jararaca. We evaluated three morphological characters of 342 specimens: number of ventral scales (proxy for vertebrae number), snout-vent length (a linear measure of body size) and stoutness (volumetric body size). We implemented spatial regressions to evaluate the variation of morphological dimensions using climatic predictors: the minimum temperature and evapotranspiration. SVL was poorly related to minimum temperature and evapotranspiration. However, stouter individuals were found in colder places with greater evapotranspiration, following Bergmann's rule and the water conservation hypothesis. Individuals in warmer locations also had a greater number of ventral scales, reversing Jordan's rule. We showed that different selective pressures act on different morphological dimensions. Although stoutness follows Bergmann's rule, its variation would arise from an energy storage demand rather than heat conservation. Also, stoutness variation along evapotranspiration gradients could represent a mechanism to avoid hydric stress in environments with considerable climatic variations. The variation in vertebrae number along temperature gradients could be related to ecological factors and foraging. We highlight that physioecological mechanisms to deal with climatic variation and ecological aspects could be identified in snakes through intraspecific analyses, contrasting with interspecific studies that can hardly detect general trends. Due to different environmental effects on body size, we shed new light on the importance of exploring multiple morphological dimensions in macroecological studies. (AU)

Processo FAPESP: 12/09156-0 - Sistemática filogenética, biogeografia e revisão taxonômica do grupo Bothrops jararaca (Serpentes, Viperidae)
Beneficiário:Fausto Erritto Barbo
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 20/12658-4 - Desafios para a conservação de anfíbios e répteis escamados, com ênfase na fauna brasileira: de informações básicas às ações de conservação
Beneficiário:Marcio Roberto Costa Martins
Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático
Processo FAPESP: 14/23677-9 - Novas abordagens de ecologia e conservação: diversidade filogenética e funcional de anfíbios e serpentes da Mata Atlântica brasileira
Beneficiário:Ricardo Jannini Sawaya
Modalidade de apoio: Auxílio à Pesquisa - Regular