Long-distance colonization and radiation in gekkonid lizards, Tarentola (Reptilia : Gekkonidae), revealed by mitochondrial DNA sequences

Morphological systematics makes it clear that many non-volant animal groups have undergone extensive transmarine dispersal with subsequent radiation i n new often island, areas. However, details of such events are often lackin g. Here we use partial DNA sequences derived from the mitochondrial cytochr ome b and 12S rRNA genes (up to 684 and 320 bp, respectively) to trace migr ation and speciation in Tarentola geckos, a primarily North African clade w hich has invaded many of the warmer islands in the North Atlantic Ocean. Th ere were four main invasions of archipelagos presumably by rafting. (i) The subgenus Noetarentola reached Cuba up to 23 million years in (Myr) ago, ap parently via the North Equatorial current, a journey of at least 6000 km. ( ii) The subgenus Tarentola invaded the eastern Canary Islands relatively re cently covering a minimum of 120 km. (iii) The subgenus Makariogecko got to Gran Canaria and the western Canary Islands 7-17.5 Myr ago, either directl y from the mainland or via the Selvages or the archipelago of Madeira, an e xcursion of 200-1200 km. (iv) A single species of Makariogecko from Gomera ol Tenerife in the western Canaries made the 1400 km journey to the Cape Ve rde Islands up to 7 Myr ago by way of the south-running Canary current. Man y journeys have also occurred within archipelagos, a minimum of five taking place in the Canaries and perhaps 16 in the Cape Verde Islands. Occupation of the Cape Verde archipelago first involved an island ill the northern gr oup, perhaps Sao Nicolau, with subsequent spread to its close neighbours. T he eastern and southern islands were colonized from these northern islands, at least two invasions widely separated in time being involved. While ther e are just three allopatric species of Makariogecko in the Canaries, the si ngle invader of the Cape Verde Islands radiated into five, most of the isla nds being inhabited by two of these which differ in size. While size differ ence may possibly be a product of character displacement in the northern is lands, taxa of different sizes reached the southern islands independently.