Maghreb Wheatear (Oenanthe halophila) could be a new North African endemic

Schweizer, M. & Shirihai, H. (2013). Phylogeny of the  Oenanthe lugens complex (Aves, Muscicapidae: Saxicolinae): Paraphyly of a morphologically cohesive group within a recent radiation of open-habitat chats. Molecular Phylogenetics and Evolution 69 (3): 450–461. doi: 10.1016/j.ympev.2013.08.010

The new phylogenetic study was inconclusive regarding the split of the Maghreb Wheatear (Oenanthe halophila) from the Mourning Wheatear complex. However, it should be split by applying the integrative approach toward species delimitation as was applied in other cases including in the genus Oenanthe

La nouvelle étude phylogénétique n’a pas été concluante en ce qui concerne l’élévation au rang d’espèce du Traquet halophile Oenanthe halophila (c’est-à-dire le “split” entre ce taxon et le Traquet deuil Oenanthe lugens). Cependant, il devrait être “splité” en appliquant l’approche intégrative à la délimitation des espèces, comme cela a été appliqué dans d’autres cas, y compris dans le genre Oenanthe

Abstract:

The morphologically inferred Oenanthe lugens complex comprises nine taxa of open-habitat chats which occur in rocky and/or mountainous areas adjacent to the Saharo-Sindian desert belt. It has traditionally been divided into the lugubris group of north-east Africa, the lugentoides group of the southern part of the Arabian Peninsula and the lugens group of North Africa and the Middle East. Previous molecular phylogenetic studies have shown that the O. lugens complex might not be monophyletic. However, it remained unclear how this result might have been affected by incomplete taxon sampling, as the lugentoides group and two out of three taxa of the lugubris group have not been analyzed so far. In this study, we present a phylogenetic hypothesis of the O. lugens complex based on two mitochondrial genes and one nuclear intron using, for the first time, a complete taxon sampling. The application of a multispecies coalescent approach allowed us to simultaneously estimate the sequence and timing of speciation events.

The O. lugens complex was consistently revealed as a polyphyletic assemblage and the traditionally recognized groups should be treated as at least three different species: O. lugens, Oenanthe lugubris, and Oenanthe lugentoides. While O. lugubris and O. lugentoides were revealed to be sister groups, O. lugens was found to be closely related to the species pair Oenanthe chrysopygia/Oenanthe xanthoprymna. The latter differ quite strongly in morphology and have traditionally not been associated with members of the lugens complex. We thus corroborate the results of previous studies, which demonstrated that morphology seems to be a poor predictor of phylogenetic relationships in Oenanthe. In contrast to the mtDNA markers analyzed, it was revealed that differences among taxa were not fixed in the nuclear intron. In the case of the taxa persica of the lugens group, an influence of introgression in autosomal markers cannot be excluded and deserves further study. The three species O. lugens, O. lugubris, and O. lugentoides and their associated taxa comprise a comparatively young radiation, which started to diversify in the Pliocene with major diversification events during the Pleistocene. The different taxa seem to have evolved during periods of increased aridity in isolation in rocky mountainous areas adjacent to hyper arid regions.

Distribution of the 9 different taxa of Oenanthe lugens complex

Distribution of the 9 different taxa of Oenanthe lugens complex. Molecular Phylogenetics and Evolution. doi:10.1016/j.ympev.2013.08.010

Maghreb Wheatear - Traquet halophile - Oenanthe (lugens) halophila, Batna, Algeria

Maghreb Wheatear – Traquet halophile (Oenanthe halophila), Batna, Algeria (photo: Raouf Guechi)

Phylogeographic history of the Houbara–Macqueen’s bustard complex as revealed by mitochondrial DNA

Korrida, A. and Schweizer, M. (2014). Diversification across the Palaearctic desert belt throughout the Pleistocene: phylogeographic history of the Houbara–Macqueen’s bustard complex (Otididae: Chlamydotis) as revealed by mitochondrial DNAJournal of Zoological Systematics and Evolutionary Research 52 (1): 65-74. doi: 10.1111/jzs.12036

Abstract:

Studies on the influence of Pleistocene climatic fluctuations and associated habitat changes on arid-adapted bird species living in the Holarctic region are comparatively rare. In contrast to temperate species, the populations of arid-adapted avian species might be characterized by low genetic differentiation because periods of population isolation were associated with the short interglacial periods, while population expansion events might have occurred during the longer glacial periods when steppe-like vegetation might have been prevalent. In this study, we tested this hypothesis in a widespread arid-adapted taxon of the Palaearctic desert belt, the Houbara–Macqueen’s bustard complex. The later includes the Houbara bustard Chlamydotis undulata, comprising the North African subspecies Chlamydotis u. undulata and Chlamydotis u. fuertaventurae from the Canary Islands, and the Asian Macqueen’s bustard Chlamydotis macqueenii. A long fragment (1042 bp) of the Cyt-b gene was investigated in 39 representatives of the two species to assess phylogenetic and phylogeographic patterns, and demographic history and to compute divergence time estimates using a Bayesian relaxed molecular clock approach based on different coalescent priors. While the two species are genetically distinct, we found little intraspecific genetic differentiation. The divergence time of the two species falls within a period of extreme aridity at around 0.9 million years ago, which most likely resulted in an east–west vicariance along the Arabo-Saharan deserts. Differentiation within Houbara and Macqueen’s bustard occurred later during the Middle to Upper Pleistocene, and as we have predicted, periods of range expansion were associated to the last glacial period at least in the Macqueen’s bustard.