Quaternary biodiversity of the giant fossil endemic lizards from the island of El Hierro (Canary Islands, Spain)

Abstract

The genus Gallotia is an endemic lizard clade from the volcanic archipelago of the Canary Islands (Spain). This clade has five extant and extinct giant species distributed over just five islands in the archipelago: El Hierro, La Gomera, La Palma, Tenerife and Gran Canaria. On the island of El Hierro, remains of several giant species of Gallotia have been found. In this paper, we present a revision and description of the bones from El Hierro with similar osteological characteristics to the giant species from Tenerife, Gallotia goliath. The fossil remains of 24 individuals have been found in volcanic tubes of a Chibanian/upper Pleistocene-Holocene age (Quaternary). These remains confirm the presence of the species Gallotia goliath on the island of El Hierro and provide the first evidence of the possible coexistence of two giant fossil species of Gallotia on the same island. The existence of individuals of Gallotia goliath would imply on the one hand dietary specialization each giant species. On the other hand, it would suggest the transfer of non-flying species between islands raising the possibility that the great landslides of the Quaternary may have played an important role in inter-island migrations.