Plumage based classification of the bowerbird genus Sericulus evaluated using a multi-gene, multi-genome analysis

Abstract

Past classifications of taxa within the bowerbird genus Sericulus (family: Ptilonorhynchidae) conflict since the discovery of hybrids identified though male plumage characteristics. We use molecular data to help define species within this genus, and by estimating a phylogeny, test for lability in the evolution of male plumage patterns. Because this genus includes the most brightly colored bowerbird species, and is hypothesized to be the basal genus of the avenue building bowerbird clade, the organization of the four taxa within this genus is especially important in understanding how bowerbird plumage coloration evolved. Analyses of two mitochondrial and six nuclear gene regions confirm the basal placement of Sericulus in the avenue building bowerbirds and Sericulus monophyly, and suggests the Australian S. chrysocephalus is the basal Sericulus species. Our analysis additionally supports the existence of three New Guinea Sericulus species, contrary to some previous plumage based classifications, as they are genetically equidistant from each other. Molecular and geographic data of New Guinea are consistent suggesting a series of speciation events starting approximately 3.7-4.3MYA leading to four extant Sericulus species. The absence of resolution within the New Guinea species precludes any statements of trait lability, but does suggest that traits under high selection pressures may not accurately indicate species level distinctions within this genus.