Relationships within the Australo-Papuan Fairy-wrens (Aves : Malurinae) : an Evaluation of the Utility of Allozyme Data

Abstract

Allozyme variation at 39 presumptive loci was screened across 180 specimens representing 18 species of Australo-Papuan fairy-wrens (Maluridae). The results identified two major clusters within Malurus. One comprised M. cyaneus, M. splendens, M. coronatus, M. melanocephalus, M. leucopterus and M. alboscapulatus. The other comprisedM. lamberti, M. amabilis, M. pulcherrimus and M. elegans. M. grayi and M. cyanocephalus were variously associated with these two assemblages. Most analyses aligned Clytomias with Malurus relative to Stipiturus. The findings from the present study indicate that allozyme data are well suited to phylogenetic inference whether analysed as distances or as discrete characters, provided that only relatively robust branches are accepted. When only such branches were considered there was complete congruence between the analyses. Nevertheless, congruence per se between analyses was not necessarily a reflection of robust branching patterns, as illustrated by the position of Clytomias. Of analyses with discrete characters, those that treated loci as characters and the commonest allele as the state appeared to be a particularly effective approach, provided that the distribution of discarded alleles in the initial topology is considered a posteriori. The allozyme data confirmed several previously accepted lineages, and identified surprising new links between several taxa as well. These links were supported biogeographically and, in some aspects, morphologically. Those phylogenetic nodes that were poorly resolved can now be tested by more sensitive DNA-based approaches. By using allozymes to establish robust clades and then to identify areas in need of further resolution, DNA-based studies can be focused better on phylogenetic problem areas, thereby promoting more efficient use of time and resources.