Molecular data exclude current hybridization between iguanas Conolophus marthae and C. subcristatus on Wolf Volcano (Galápagos Islands)

Natural hybridization may influence population fitness and responsiveness to natural selection, in particular in oceanic island systems. In previous studies, interspecific hybridization was detected between the Galápagos iguana species Amblyrhynchus cristatus and Conolophus subcristatus. Further, possible hybridization was also suggested to occur between C. subcristatus and C. marthae at Wolf Volcano on Isabela Island. In this work, we investigated the level of hybridization between C. subcristatus and C. marthae using a large set of microsatellite markers. Results indicated strong differentiation between species and, while we cannot rule out hybridization in the past, there is no evidence of ongoing hybridization between C. marthae and C. subcristatus. These findings have great importance for the design of management actions and conservation plans, in particular for the purposes of a head start program. However, because potential for hybridization may change under different environmental and demographic conditions, genetic characterization of newly marked individuals of C. marthae and C. subcristatus in Wolf Volcano should not be interrupted.