Characterization of the venom and external morphology of a natural hybrid between Crotalus atrox and Crotalus mictlantecuhtli.

Here we report, for the first time, a natural hybrid between Crotalus atrox and C. mictlantecuhtli based on intermediate characteristics of the external morphology and venom. Morphologically, the individual had characteristics of both parent species. The hybrid's venom exhibited an intermediate composition including the presence of crotoxin which has never been documented in C. atrox but is well documented in C. mictlantecuhtli. The hybrid's venom was highly toxic and showed an intermediate proteolytic activity between the parental species. The two Mexican antivenoms were able to neutralize the hybrid's venom's lethality. [Display omitted] • Hybridization between Crotalus atrox and C. mictlantecuhtli is documented for the first time. • The external morphology of the hybrid exhibited characteristics of both parental species. • The venom of the hybrid presented intermediate venom composition between C. atrox and C. mictlantecuhtli. • The hybrid's venom has high lethal activity due to the presence of a crotoxin-like molecule. [ABSTRACT FROM AUTHOR]