Origin and evolution of the unique Australo-Papuan mangrove- restricted avifauna: novel insights form molecular phylogenetic and comparative phylogeographic analyses

Abstract

Coastal mangrove forests of Australo-Papua harbor the world's richest avifauna restricted to mangroves, however their biogeographic origins and evolutionary processes shaping their current distributions are not well understood. Building upon previous work based on field surveys and morphological characters, I am here focusing on elucidating the phylogenetic placement of mangrove-bound species from three different bird families as well as the comparative phylogeographic analysis of eight co-distributed mangrove restricted birds. In the first molecular phylogenetic analysis of fantails (Aves: Rhipiduride) I document six distinct clades, harboring members spread across large geographic extents. Rhipidura hypoxantha is not a true fantail, but rather a member of the Stenostiridae clade that is morphologically and behaviorally convergent with fantails. The Australian mangrove fantails R. phasiana and R. dryas both evolved recently from Pacific island radiations. A molecular phylogeny of all extant species of the honeyeater genus Lichenostomus (Aves: Meliphagidae) also addresses the relationship of the only mangrove-restricted honeyeaters on Australia's east coast, L. versicolor and L. fasciogularis. These species were not sisters but rather L. versicolor was sister to the pair comprising L. fasciogularis and the continental widespread Singing Honeyeater L. virescens. The genus Lichenostomus is not monophyletic, and instead comprises seven distinct lineages interdispersed within the larger meliphagid assemblage. Based on this taxonomic and nomenclatural revision, recognition of a novel genus of honeyeater is warranted. A multilocus molecular phylogeny of gerygones (Aves; Acanthizidae) establishes that the three mangrove endemic species do not form a monophyletic clade, instead indicating three distinct, temporally non-overlapping, radiations into magroves. Moreover, G. cinerea from New Guinea is in fact a member of the genus Acanthiza, with which it consistently grouped based on 13 distinct molecular loci analyzed. Comparative phylogeographic analyses of 8 co-distributed mangrove forest endemic birds concludes biogeographic barriers such as the Canning Gap, Bonaparte Gap, and the Carpentarian Gaps all had important, but varying degrees of impact on the species we analyzed. Species with more recent radiations into mangroves include Rhipidura phasiana, Myiagra ruficollis, and Myzomela erythrocephala, while Peneoenanthe pulverulenta, Pachycephala melanura, P. lanioides, Zosterops luteus, and Colluricincla megarhyncha all had more marked phylogeographic signatures.