Genetic and Morphological Differentiation and Phylogeny in the Australo-Papuan Scrubwrens (Sericornis, Acanthizidae)

Abstract

Abstract The interrelationships of 13 of the 14 species currently recognized in the Australo-Papuan oscinine scrubwrens, Sericornis, were assessed by protein electrophoresis, screening 44 presumptive loci. Consensus among analyses indicated that Sericornis comprises two primary lineages of hitherto unassociated species: S. beccarii with S. magnirostris, S. nouhuysi and the S. perspicillatus group; and S. papuensis and S. keri with S. spilodera and the S. frontalis group. Both lineages are shared by Australia and New Guinea. Patterns of latitudinal and altitudinal allopatry and sequences of introgressive intergradation are concordant with these groupings, but many features of external morphology are not. Apparent homologies in face, wing and tail markings, used formerly as the principal criteria for grouping species, are particularly at variance and are interpreted either as coinherited ancestral traits or homoplasies. Distribution patterns suggest that both primary lineages were first split vicariantly between Australia and New Guinea, and then radiated independently on each land mass under the influence of paleoclimatic change. Dispersal between Australia and New Guinea is indicated only in the magnirostris sublineage and is either very recent or just broken.