Molecular and Morphological Evidence of Distinct Evolutionary Lineages of Awaous guamensis in Hawai'i and Guam
Questions remain about the taxonomy and distribution of geographically widespread species in the circumtropical gobiid genus Awaous. Previous work that placed two species in synonymy on the basis of morphological characteristics effectively redefined the range of Awaous guamensis to include distant locations from Hawai'i and Guam to the islands of South-East Melanesia. Here we evaluate the synonymy of A. guamensis and A. stamineus through phylogeographic analysis of mitochondrial DNA sequence variation and morphological comparisons of Hawai'i and Guam populations. Phylogenetic assessments show clear separation of molecular characteristics, and morphological analyses illustrate statistically significant phenotypic differences indicating that the populations represent distinct evolutionary lineages. Based upon genetic, morphological, and geographic distributional differences, we recommend that Hawaiian populations be recognized as a distinct species, and reversion to the previous nomenclature of Awaous stamineus.
Indo-Pacific sampling locations and species identifications of present and previous (Watson, 1992) studies. Blue markers indicate collection sites and species distinctions of present study. Red markers indicate collection sites and species distinctions of Watson (1992).
Phylogenetic relationships of select species of Awaous in the Pacific and Caribbean. Maximum likelihood analysis of mtDNA cytochrome b sequences supporting four distinct lineages corresponding to A. guamensis (green), A. stamineus (red), A. ocellaris (orange), and A. banana (blue). Nodal support is indicated by maximum likelihood (above node) and maximum parsimony bootstrap replicates (below node). Hash marks on branches indicate those that were shortened for aesthetic reasons. Double hash marks indicate a shortening of 0.03 and triple hash marks 0.12.
Discriminant Analysis of PC factors based on morphological traits of species of Awaous from Hawai'i (filled circles) and Guam (open circles) with 95% confidence intervals.
Contributor Notes
Associate Editor: D. Buth.