Phylogenetic analysis of the tribe Oryzomyini (Muroidea: Sigmodontinae) based on morphological and molecular data.
Item
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Title
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Phylogenetic analysis of the tribe Oryzomyini (Muroidea: Sigmodontinae) based on morphological and molecular data.
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Identifier
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AAI3159266
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identifier
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3159266
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Creator
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Weksler, Marcelo.
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Contributor
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Adviser: Robert S. Voss
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Date
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2005
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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
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Abstract
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The present thesis provides a comprehensive hypothesis of evolutionary relationships for the Oryzomyini, the largest tribe of the Neotropical subfamily Sigmodontinae (Rodentia: Muroidea).;In the first chapter, partial sequences (1266 bp) from the first exon of the nuclear gene encoding the Interphotoreceptor Retinoid Binding Protein (IRBP) were used to infer the phylogenetic relationships among 44 species representing all 16 currently recognized genera of Oryzomyini. Monophyly of the tribe was assessed relative to 15 non-oryzomyine sigmodontine taxa. The resulting matrix included 71 taxa and 386 parsimony-informative characters. Phylogenetic analysis resulted in 16 equally parsimonious cladograms, which contained the following well-supported groups: (1) a monophyletic Oryzomyini, (2) a clade containing all oryzomyines except Scolomys and Zygodontomys, (3) a clade containing Oecomys, Handleyomys, and several species of forest-dwelling Oryzomys , and (4) a clade containing the remaining oryzomyine taxa. The last clade is composed of two large subclades, each with lower nodal support, containing the following taxa: (1) Microryzomys, Oligoryzomys, Neacomys, and Oryzomys balneator; (2) Holochilus, Lundomys, Pseudoryzomys, Nectomys, Amphinectomys, Sigmodontomys , and several species of open-vegetation or semiaquatic Oryzomys.;In the second chapter, the IRBP dataset was complemented with a morphological matrix comprised of 99 characters, including 16 integumental characters, 32 skull characters, 29 dental characters, 7 postcranial characters, and 10 characters from the phallus and soft-anatomy systems. I present anatomical descriptions for each character, with the delineation of different states observed among oryzomyines. Separate and combined analyses were performed using the molecular and morphological datasets. Results of the combined analysis were congruent with the IRBP-only dataset for oryzomyine higher-level relationships. Morphological analyses, although showing discrepancies from the combined or IRBP consensus cladograms and with low nodal support values, recovered several clades similar to the combined and IRBP analyses. The systematics of the tribe and the evolution of a few pivotal characters are discussed in light of the proposed phylogeny. A new taxonomy of species currently included in the genus Oryzomys is proposed. Finally, I evaluate evolutionary and biogeographic hypotheses that are compatible with our current knowledge on oryzomyine relationships.
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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.
