Squamate reptiles from prehistoric sites in the Mariana Islands

Fossil remains of lizards on Pacific islands are uncommon. Where known, they are a unique source of information for assessing patterns of dispersal and extinction. Paleontological and archaeological excavations conducted in 1995 on Rota, Aguiguan, and Tinian yielded hundreds of bones of 12 species of lizards and one snake from historic and prehistoric age strata. The lizards include all six gecko species presently known in the Marianas and at least four of the skinks. Five species identified from Aguiguan are unknown there today as is another from Rota, Bones of an unidentified gekkonid lizard were also recovered from the three islands but cannot be referred to any genus presently known in Micronesia, The blind snake cf. Ramphotyphlops braminus is present in prehistoric and prehuman levels, demonstrating that it is a naturally occurring member of the herpetofauna. All of the species that are supposedly native in the Marianas occurred in some strata of prehistoric age except for Gehyra oceanica and G. mutilata, which were restricted to a few historic horizons. The nonnative monitor, Varanus indicus, only occurred in two sites of historic age. The most abundantly represented species at all sites are the gecko Perochirus ateles and the skink Emoia slevini. Both of these species have narrower distributions in the Marianas today, and E, slevini apparently achieved a substantially larger snout-vent length (to 110 mm) than that of modern voucher specimens.