Genetic data from the extinct giant rat from Tenerife (Canary Islands) points to a recent divergence from mainland relatives. Analysis of Canaoriomys bravoi mitochondrial dna

The Canary Islands are located northwest off the coast of Africa; despite a shortest distance to the continent slightly over one hundred kilometres, these volcanic islands were never connected to the mainland by a land bridge. However, the dominant oceanic circulation moves approximately from the continent towards the islands. This archipelago offers a unique opportunity to study the evolutionary origins and adaptations of endemic birds, bats, reptiles and small mammals that colonized it. Among the latter, there are two extinct examples of rodent gigantism: the giant rats of Tenerife and Gran Canaria (Canariomys bravoi and Canariomys tamarani, respectively). Hot and humid thermal conditions hamper the retrieval of genetic data, making difficult to unravel the affinities of these extinct species to their mainland, smaller relatives. We have retrieved partial nuclear and mitochondrial (mtDNA) data from one C. bravoi specimen; we subsequently used this information to calculate the divergence time and estimate the rate of increase in body size for this insular rodent.