PHYLOGENY AND HISTORICAL ASPECTS OF THE ECOLOGY OF EASTERN AUSTRALIANSCRUBWRENS SERICORNIS SPP - EVIDENCE FROM MITOCHONDRIAL-DNA

A phylogeny of mainland eastern Australian scrubwrens (Sericornis citr eogularis, S. frontalis, S. keri, S. magnirostris and S. beccarii) was constructed using presence or absence of phylogenetically informative restriction sites in 15 mitochondrial DNA (mtDNA) haplotypes. MtDNA s equence divergences between species were generally large (mostly betwe en 10 and 18%) emphasizing the antiquity of this radiation. Phylogenet ic analysis of the mtDNA resulted in a strongly supported phylogeny co ncordant with relationships suggested by a previous study of allozyme variation, but conflicting with concepts based on morphological simila rity. The mtDNAs grouped the species into two lineages, one containing beccarii and magnirostris and the other comprising citreogularis, fro ntalis and keri. The mtDNAs of beccarii and magnirostris were paraphyl etic with a northern variant of magnirostris being more similar to bec carii than other magnirostris. The mtDNA from keri was most closely re lated to that of frontalis and then citreogularis. The strongly corrob orated molecular phylogeny confirms and extends the previous (Christid is et al. 1988; Auk 105: 616) reinterpretation of morphological and ec ological shifts in the group. This suggests considerable plasticity an d parallelism in the plumage characters previously used to associate s pecies. The low divergence and close relationship between the montane rain-forest specialist keri and the widely distributed generalist fron talis demonstrate the capacity for evolutionarily rapid and dramatic s hifts in habitat use. This contrasts with the assumption of fixed habi tat preference that underlies refuge-based models of diversification o f rain-forest fauna.