| This research was designed to provided the first detailed phylogenetic and biogeographic analyses of passerine birds endemic to the Guineo-Congolian biome. The phylogenetic species concept was used to delineate basal evolutionary units in each of five genera (Stiphrornis, Bleda, Criniger, Alethe and Sheppardia), and their interspecific relationships and phylogeographic pattern were explored with DNA sequence data.; Each of the phylogenetic species recognized by external morphological characters (revealed by a survey of museum specimens) was corroborated by the mitochondrial DNA sequence data, which also showed relatively high levels of sequence divergence among the species. Certain biogeographic elements of the systematic patterns of Stiphrornis, Bleda and Criniger were shared and together allowed for a preliminary identification of areas of endemism and a hierarchy of vicariant events. These findings clarified phylogenetic and spatial patterns otherwise obscured when the taxa in these groups are classified as more inclusive (e.g. “biological”) species, and they highlight the need for critical taxonomic revision of parts of the African avifauna. Phylogenetic relationships between species of akalats ( Sheppardia, Aves: Turdidae) and alethes (Alethe, Aves: Turdidae) were also explored in order to clarify the historical biogeography of the two groups, which also have species occurring outside the lowland rainforest biome. While the composition of some species groups recognized in prior revisions of these genera were corroborated with the molecular data, these data gave little support for the monophyly of either Alethe or Sheppardia as those genera are currently circumscribed and show that many “Cossypha” allied to Sheppardia .; Phylogeographic pattern was also investigated in four species widespread in the Guineo-Congolian biome (Bleda syndactyla, Criniger calurus, Sheppardia cyornithopsis and Alethe poliocephala), and for Alethe castanea in the Congolian region. Within widespread species, some phylogeographic elements were shared, such as distinct lineages between Upper and Lower Guinea populations, and between eastern and western Congolian populations. This study revealed previously unknown mitochondrial diversity among closely related species and within widespread populations; in most cases strong geographic structure was evident in the gene trees and indicates the need for future studies to clarify the processes responsible for that phylogeographic structure. |
