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Mathematisch-Naturwissenschaftliche Fakultät - Jahrgang 2003


Titel Taxonomy, Phylogeny, and Biogeography of the Andean Hummingbird Genera Coeligena LESSON, 1832; Pterophanes GOULD, 1849; Ensifera LESSON 1843; and Patagona GRAY, 1840 (Aves: Trochiliformes)
Autor Carlos Sánchez Osés
Publikationsform Dissertation
Abstract In this study the taxonomy, phylogeny, and biogeography of the Andean hummingbird genera Coeligena Lesson, 1832, Pterophanes Gould, 1849, Ensifera Lesson, 1843, and Patagona Gray, 1840 is analysed and reconstructed. Geographic variation in the study taxa was determined based on external characters, such as plumage coloration patterns and morphometric parameters. On this basis, taxonomic modifications were proposed. The study material consisted of museum specimens deposited in international ornithological collections. Once the taxomony was clarified, a phylogenetic reconstruction was carried out. For this purpose, a matrix with the coloration characters of all the species was constructed. The phylogenetic relationships were reconstructed using the method of succesive character weighting. For the analysis the software PAUP* was employed. The dependence of the phylogeny of the taxa on the geological history of their geographic ranges was tested, in this case the speciation and radiation scenarios and the uplift progression of the Andes. Vicariance processes were assumed to be the main factors modelling the speciation events within the taxa studied. To test this hypothesis, a Brook's Parsimony Analysis (BPA) was performed. The BPA analysis was based on the phylogenetic reconstruction obtained in this study. A biogeographic hypothesis applicable to other related Andean taxa is proposed. The taxomomic, phylogenetic, and biogeographic conclusions of this study are:
- The genus Coeligena includes 17 species, and of these species, three were newly promoted to the category: C. conradii, C. insectivora (formerly considered subspecies of C. torquata), and C. aurora (formerly considered a subspecies of C. iris). The species included in the monotypic genera Pterophanes and Ensifera are now included in Coeligena: Coeligena cyanopterus and Coeligena ensifera.
- The subspecies C. iris flagrans is not considered valid, and is probably a product of intergradation between the subspecies C. iris iris and C. iris eva.
The geographic ranges of Coeligena and Patagona species and subspecies were corrected and in some cases extended.
- Coeligena is a monophyletic group with Heliodoxa as sister group, evidence not being found for the inclusion of Patagona within this clade. Coeligena subdivided very early into two main clades: one including the torquata-like species with the remainding species as sister group. This division reveals a parallel speciation process within the genus. C. ensifera and C. cyanopterus belong to the non-torquata sister group, showing strong relationships within Coeligena clades, confirming their close phylogenetic relatedness. These relationships need to be confirmed by means of further studies based on evidence other than plumage coloration.
- Within the non-torquata forms, two subdivision are distinguishable: one including the least sexually dimorphic species of Coeligena and the other including the extremely dimorphic forms. The low-altitude monomorphic northern coeligena-like species are grouped into one separate clade.
- An early origin is proposed for the Coeligena species (Miocene) and, like other Andean taxa, their radiation and speciation responded to the progressive uplifting of the Andes.
- The centre of origin for Coeligena is proposed as being located in southern Peru. The later dispersal and radiation followed the formation of the mountain range northwards and possibly southwards, considering the asymmetric orogenic history of the Andes.
- The separation of ancestral populations by vicariance events promoted the speciation and differentiation of the extant taxa. The last uplift of the northern Andes, and the subsequent Pleistocene climatological changes, influenced and still influence the finer subdivision and isolation of the population's thus promoting the formation of new taxa.
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© Universitäts- und Landesbibliothek Bonn | Veröffentlicht: 2003