The phylogenetic relationships of the major clades of birds remain unresolved and controversial. No single type of data has been able to resolve these relationships owing to lack of resolution at different time scales. The most significant impediment, probably, is that avian phylogeny is characterised by numerous star phylogenies. Branching topologies are characterised by short internodes, thus all molecular data have been subject to long-branch attraction artefacts, and it has proven difficult to find a sufficient number of derived characters, both molecular and morphological, to delineate most lineages clearly. We report here results from a combined analysis including over 5000 bp of mitochondrial sequences and one of the largest morphological data sets assembled to date for most of the major clades of birds. Relationships are still resolved unsatisfactorily because of the reasons already stated. Long-branch attack artefacts seem to affect mitochondrial sequences and DNA-hybridisation in many of the same ways. Different approaches to analysis yield different, and sometimes significantly conflicting, results. Suggestions are made as to how the phylogenetic information of these data sets might be enhanced. 

Key words: phylogeny, mitochondrial sequences, combined analysis

Up to recently, Class Aves were considered to be the only vertebrate group that evolved monophyletically from some reptiles via Archaeopteryx. However, evidence has accumulated during past years that indicate an unbelievable diversity of Mesozoic birds, and complicate our understanding of early avian evolution. These principal discoveries are Infraclass Enantiornithes from the Cretaceous, the diversity of hesperornithiforms and their distribution across the Old World, the origin of Neornithes at least from early Cretaceous, the presence of four orders of neornithine birds of the basic recent characters in the late Cretaceous, distribution of paleognathes in Cretaceous and Paleogene, and description of Protoavis (late Triassic, Texas, USA) as a probable ancestor of ornithurinae birds. These data confirm that basal evolution of birds belongs to a period before Archaeopteryx. Nowadays, it is considered that Sauriurae (Archaeopteryx + Enantiornithes) and Ornithurae are two parallel lineages in avian evolution. Confuciusornis well supports the unity of Archaeopteryx and Enantiornithes, all the main lineages of Ornithurae existed in the early Cretaceous yet, and that the highest avian taxa, such as Enantiornithes, Hesperornithes, Ichthyornithes, Palaeognathae, and Neognathae, existed simultaneously on the Earth throughout more than half (80 my) of the known history of birds. 

Key words: Mesozoic birds, diversity, avian paleontology, Archaeopteryx, Enantiornithes

Although ornithologists are familiar with the historical importance of the Dahomey Gap as a major barrier dividing the African lowland forest block, less is known about the number or identity of any Pleistocene refugia within the Lower Guinea forest. Hall & Moreau's (1970) atlas of passerine distributions showed distinct biases in sampling intensity against western central Africa, and recent collecting efforts by the American Museum of Natural History highlighted the insufficient nature of our knowledge about the avifauna of the western central forest. This relative lack of knowledge combined with historical emphasis on the biological species concept has obscured the complexity of a region that has been affected by at least three purported refugia presently identified by the Cameroon, Gabon-coastal and eastern Congo areas of endemism. In order to investigate the contribution of each purported Pleistocene refuge, mitochondrial-DNA sequence data were analysed among several avian families, including Alcedinidae, Turdidae, Pycnonotidae and Muscicapidae for which levels of molecular divergence within and between species were compared. Biogeographical patterns predicted by external morphology and distributional data collected in museums and in the field were compared with those suggested by the molecular data to propose a refined understanding of the effect of history on the composition of the contemporary central African rainforest avifauna. 

Key words: biogeography, African lowland forest, mitochondrial DNA, speciation, conservation

Helbig, A.J. & Seibold, I. 1998. Three Sylviid radiations: Comparative phylogeny and evolution of Old World warblers (Sylvia, Acrocephalus, Phylloscopus). In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 69: 207. 

Warblers of the family Sylviidae include some of the most species-rich and morphologically least differentiated radiations of insectivorous passerines in the Old World. The phylogeny of three such groups, the leaf (Phylloscopus, Seicercus), reed (Acrocephalus, Hippolais) and Sylvia (Parisoma) warblers, was reconstructed using mitochondrial DNA sequences. Phylogenetic structure, relative age and degree of phenotypic versus genetic differentiation will be compared among the three radiations. Each group is monophyletic, but several genera as traditionally delimited proved to be paraphyletic. Genetic divergence within Sylvia and Phylloscopus is large compared to most non-passeriform genera, indicating that these taxa are phylogenetically older than previously thought. The Acrocephalus-Hippolais radiation is considerably younger. The symmetry and degree of resolution of phylogenetic tree estimates differs strikingly between the groups. Genetically most similar sister taxa are allopatric or parapatric, indicating that probably the only mode of speciation in these birds is allopatric. Phenotypic characters (morphology, behaviour, range) will be mapped onto the phylogenies to estimate the phylogenetic component of character evolution. Body size, plumage and bare part colouration and location of breeding range are relatively conservative, mating system, migration behaviour and associated morphology are labile evolutionarily. Comparisons with other phylogenetically well-known bird groups support the generality of these findings. 

Key words: phylogeny, Sylviidae, mitochondrial DNA, character evolution, speciation

The genus Phoenicurus consists of 10 or 11 species in Eurasia. However, the considerable number of intermediary forms in transition zones and occasional hybrids can make identification of individual forms rather difficult. Therefore the MPI has started a ‘Phoenicurus – Project’ to obtain a detailed insight into the phylogeny and evolutionary processes of this group. To support the classical methods of research (i.e. morphological, ethological, hybridisation and migration studies), it was necessary to obtain additional genetic information. To get as strong evidence as possible, this was done by combining analysis of nuclear DNA (microsatellites) with sequencing of mitochondrial DNA (Cytochrome-b gene). The chosen microsatellite-loci vary gradually in their evolution rates, so the phylogeny of near as well as more distantly related taxa could be resolved. The results emphasize phylogenetic context of speciation and support the hypothesis that hybridisation plays an important role in speciation processes, especially within the complex P. ochruros, P. phoenicurus, P. hodgsoni, P. auroreus and P. frontalis, as was recently shown in the Darwin’s finches on the Galapagos islands. This view sheds new light on the species concept in animals and on the evolution and diversity of organisms in general. 

Key words: hybridisation, evolution, speciation, cytochrome-b, microsatellite

Common views on relationships of the obligate brood parasitic finches are that cuckoo-finch Anomalospiza is most closely related to the weavers Ploceidae, while viduines Vidua spp. independently evolved as a brood parasitic clade, either from weavers or from the grassfinches Estrildidae. DNA sequences of the mitochondrial 12S, ND1, and ND2 genes were determined for the African brood-parasitic finches and representatives of other finch and sparrow groups. Phylogenetic analysis indicates that the brood parasites are monophyletic: Anomalospiza and Vidua are each other's closest relatives. Our results indicate that brood parasitism evolved only once among the extant brood-parasitic African finches and that this lineage has been parasitic for millions of years. In addition, the parasitic finches are neither grassfinches (Estrildidae) nor weavers (Ploceidae), but represent a third distinct group. These three groups are more distantly associated with sparrow (Passeridae) and other Old World finches (Carduelidae, Emberizidae). Within Vidua, the short-tailed indigobirds (V. chalybeata and nine other species) are a monophyletic, derived clade, with V. regia and V. fischeri the sister clade of this group. The all-black plumaged V. hypocherina is not closely related to the all-black plumaged indigobirds. 

Key words: brood parasitism, Vidua, Anomalospiza, molecular genetics, phylogeny

Differentiation of island organisms provides an opportunity to assess the roles of drift and selection in promoting divergence among populations. Morphological differentiation in island passerines follows a trend towards larger body size. To determine if selective or neutral mechanisms can account for such broad scale changes in island birds, we used populations of the Silvereye Zosterops lateralis to examine genetic and phenotypic changes following recent colonisation events and older invasions of islands of the south-west Pacific. We estimated variances and extent of divergence between island and source populations for morphological and neutral genetic characters to determine whether changes are consistent with expectations of drift or natural selection. The results indicate that significant morphometric changes can occur rapidly in Silvereyes with increased mean values for wing, head, tail, tarsus, bill depth and weight and increased variances for wing, head and bill depth on islands. Nuclear microsatellite loci can detect differentiation of populations over short time-scales and diversity is not necessarily reduced immediately following colonisation. Consistent directional changes in traits across a number of islands suggest that selection mechanisms may be operating. The results illustrate the power of combining genetic and morphological approaches when studying microevolution on islands. 

Key words: genetics, white-eye, microevolution, morphometrics, island bird

We used uniparentally and biparentally transmitted molecular markers to document limited historical hybridisation between White-crowned Zonotrichia leucophrys and Golden-crowned Z. atricapilla Sparrows. We compared 985 base pairs of sequence from the mtDNA genome and found anomalously low levels of sequence divergence between Z. leucophrys and Z. atricapilla. Sequence divergence between Z. leucophrys and Z. atricapilla ranged between zero and 0.6% , which is extremely low for a comparison between undisputed species. Divergence values calculated from allozyme markers, which are biparentally transmitted, suggest that Z. leucophrys and Z. atricapilla have been evolving independently for a considerable period. We hypothesise that during one of the recent Pleistocene glaciations a limited hybridisation event between Z. leucophrys and Z. atricapilla resulted in the introgression and subsequent replacement of one of these species mtDNA genomes by the other. This may be the first well-documented avian example of past hybridisation leading to mitochondrial DNA genome extinction. 

Key words: molecular systematics, hybridisation, introgression, speciation, DNA