Phylogenetic relationships of Geothlypis (Aves: Parulinae).
Item
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Title
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Phylogenetic relationships of Geothlypis (Aves: Parulinae).
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Identifier
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AAI9207068
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identifier
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9207068
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Creator
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Escalante-Pliego, Bertha Patricia.
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Contributor
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Adviser: Francois Vuilleumier
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Date
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1991
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Zoology | Biology, Genetics
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Abstract
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The genealogical history of 12 nominal taxa of Yellowthroats (Parulinae: Geothlypis; warblers) was reconstructed using allozyme variation at the population and species levels. Estimates of genetic population structure (F{dollar}\sb{lcub}\rm st{rcub}{dollar}, tests of heterogeneity, genetic distances) were compared across species and used to evaluate species limits. Populations of the northern species (G. trichas) were little differentiated; populations of species in Mexico (G. beldingi) and Middle America (G. poliocephala) were more differentiated; and populations of the widespread South American species (G. aequinoctialis) were more differentiated still. The amount and degree of genetic distinctness in the South American forms suggests the existence of four species in what has been considered a single species until now.;Because sound evidence for paruline relationships (or for the sister taxon of Geothlypis) is lacking, several outgroups were included to reconstruct phylogenetic relationships. Comparisons of allele frequencies across taxa showed a large amount of genetic variability shared across species and genera of parulines and thraupines sampled in this study. This pattern of variability suggests that ancestral polymorphism in allozymes is pervasive and represents an important difficulty in phylogenetic reconstruction. Several methods of analyses were employed. Distance methods (UPGMA, Fitch-Margoliash, and distance Wagner) gave different solutions compared to the other parsimony methods, perhaps due to the inclusion of several taxa with isolated ranges (marsh specialists) that could have evolved at different rates. Frequency and Wagner parsimony (alleles as characters) also gave different arrangements. Maximum likelihood and polymorphism parsimony gave very similar arrangements. These two methods use assumptions that seem to correspond better with the evolution of allozymes in lineages. The product phylogeny obtained with these two methods agrees well with variation in plumage characters, and represents the best estimate provided by the available data. According to this phylogeny Geothlypis and Oporornis together form a monophyletic taxon, but neither genus as currently recognized does by itself. The biogeographic scenario implied by this phylogeny suggests the occurrence of a population bottleneck when the common ancestor of Masked Yellowsthroats dispersed from South America across the Panama Isthmus to Central and North America, followed by rapid speciation afterwards.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
