Molecular phylogeny of Puerto Rico Bank dwarf geckos (Squamata: Sphaerodactylidae: Sphaerodactylus)

Abstract

AO_SCPLOWBSTRACTC_SCPLOWThe genus Sphaerodactylus is a very species-rich assemblage of sphaerodactylid lizards that has undergone a level of speciation in parallel to that of the well-known Anolis lizards. Nevertheless, molecular phylogenetic research on this group consists of a handful of smaller studies of regional focus (e.g., western Puerto Rico, the Lesser Antilles) or large-scale analyses based on relatively limited sequence data. Few medium-scale multi-locus studies exist-- for example, studies that encompass an entire radiation on an island group. Building upon previous work done in Puerto Rican Sphaerodactylus, we performed multi-locus sampling of Sphaerodactylus geckos from across the Puerto Rico Bank. We then used these data for phylogeny estimation with near-complete taxon sampling. We focused on sampling the widespread nominal species S. macrolepis and in so doing, we uncovered a highly divergent and morphologically distinct lineage of Sphaerodactylus macrolepis from Puerto Rico, Culebra, and Vieques islands, which we recognize as S. grandisquamis (Stejneger, 1904) on the basis of molecular and morphological characters. S. grandisquamis co-occurs with S. macrolepis only on Culebra Island but is highly genetically differentiated and morphologically distinct. Sphaerodactylus macrolepis is now restricted to the eastern Puerto Rico Bank, from Culebra east through the Virgin Islands and including the topotypic population on St. Croix. We include additional discussion of the evolutionary history and historical biogeography of the Sphaerodactylus of the Puerto Rican Bank in the context of these new discoveries.