Molecular and morphological evolution in the south-central Pacific skink Emoia tongana (Reptilia : Squamata): uniformity and human-mediated dispersal

Abstract

Human-mediated and waif dispersal are both responsible for the distribution of lizards on tropical Pacific islands. The component of each of these dispersal modes to the Pacific herpetofauna, however, is unclear. Morphological conservatism of Pacific lizards, the poor paleontological record on tropical Pacific islands, and minimal research effort in the Pacific (compared with other island systems) has hampered our understanding of waif versus human-mediated patterns. We examine morphological and genetic variation of Emoia concolor and E. tongana (formerly E. murphyi), two scincid lizards, from the south-central Pacific, to assess modes of dispersal and population structure. Emoia tongana from Tonga and Samoa is genetically uniform, suggesting that these are synanthropic populations recently introduced, presumably from Fiji. Relatively large genetic divergence is evident for populations of E. concolor within the Fijian archipelago, suggesting prehuman intra-archipelago dispersal and isolation.