HYBRIDIZATION BETWEEN THE GALAPAGOS LAND AND MARINE IGUANA (CONOLOPHUS-SUBCRISTATUS AND AMBLYRHYNCHUS-CRISTATUS) ON PLAZA-SUR

Hybridization plays an important role in the evolution of some of the vertebrate taxa on the Galapagos Islands, such as the Darwin finches. Conversely, only a single possible hybrid between the Galapagos marine iguana (Amblyrhynchus) and the land iguana (Conolophus) has been repo rted from the island Plaza Sur. In this paper, the hybrid status of a morphologically unusual iguana from this island is confirmed, using re striction fragment length polymorphism (RFLP) analyses of the nuclear ribosomal DNA (rDNA). Sequencing of the hybrid's mitochondrial cytochr ome b gene revealed that it was the offspring of a female land iguana and a male marine iguana. Preliminary molecular analyses of morphologi cally typical marine and land iguanas from Plaza Sur did not detect in trogression of nuclear or mitochondrial markers between species. Thr p otential significance of hybridization for the evolution of the Plaza Sur iguana populations is discussed.