Diversidade morfológica e molecular e fisiologia térmica das cobrascorais de Alagoas (Micrurus ibiboboca MERREM, 1820)

Abstract

New World coral snakes are the only representatives of the Elapidae family in the Americas. Micrurusis the most specious genus, with 80 species. Micrurus ibiboboca is an endemic species of Brazil, distributed throughout the Northeast, being considered a complex of species. With this taxonomic imprecision, the conservation status and how much climate change could impact this snake could not be analyzed. In this study, morphological and molecular data were used to assess diversity within M. ibiboboca in Alagoas, and the thermal physiology of the species was described. One hundred and thirty specimens of M. ibiboboca from 21 municipalities in Alagoas were morphologically analyzed. Principal Component Analyzes (PCA) were performed to verify the formation of morphogroups and Univariate and Multivariate Analyzes of Variance (ANOVA and MANOVA) to verify the existence of sexual dimorphism and intraspecific variation. Two hemipenes were prepared and described. Seventeen samples of muscle or liver tissue had their total genomic DNA extracted, and a fragment of the mitochondrial ND4 gene was amplified and sequenced. The sequences were used to generate a bayesian inference. For thermal physiology, the preferred temperature (Tpref), minimum and maximum voluntary temperatures (Vtmin and Vtmax), minimum and maximum critical temperatures (Ctmin and Ctmax) were measured and the thermal safety margin of ten individuals of M. ibiboboca was calculated. Two morphotypes based on external morphology were identified. In the female PCAs, the morphotypes were recovered with morphospace segregation, but for males there was no segregation between morphotypes. Morphotype 1 showed significant values between males and females for seven of the analyzed characters. Morphotype 2 showed significant values between males and females for two of the analyzed characters. Females showed significant values for two of the analyzed characters. Males showed significant values for three of the analyzed characters. The hemipenes are short and bilobed, ornamented with spines. The differences between the morphotypes were the number and shape of the spines. Micrurus ibiboboca from Alagoas was recovered monophyletic using molecular data. The morphotypes were not recovered in separate clades in the phylogeny. One specimen identified only as Micrurus sp. was recovered close to an individual that fits the diagnosis of another species of coral snake, M. potyguara, being the first record of the species for the state of Alagoas. Individuals of M. ibiboboca presented Tpref of 23ºC, Vtmin and Vtmax of 21°C and 25.3°C, respectively, and a thermal safety margin of 4.3ºC. Ctmin was 11.2°C and Ctmax 41°C. It was possible to observe that the species can become vulnerable if the terrestrial temperature rise by 4.5ºC. The results of this study help to understand the diversity of M. ibiboboca in Alagoas and present the first description of the thermal physiology of the species.