Results 11 -
18 of
18
MACROECOLOGICAL METHODS
"... Richness patterns, species distributions and the principle of extreme deconstruction ..."
Abstract
- Add to MetaCart
Richness patterns, species distributions and the principle of extreme deconstruction
unknown title
, 2006
"... The western diamondback rattlesnake (Crotalus atrox) is a prominent member of North American desert and semi-arid ecosystems, and its importance extends from its impact on the region’s ecology and imagery, to its medical relevance as a large deadly venomous snake. We used mtDNA sequences to identify ..."
Abstract
- Add to MetaCart
The western diamondback rattlesnake (Crotalus atrox) is a prominent member of North American desert and semi-arid ecosystems, and its importance extends from its impact on the region’s ecology and imagery, to its medical relevance as a large deadly venomous snake. We used mtDNA sequences to identify population genetic structure and historical demographic patterns across the range of this species, and relate these to broader patterns of historical biogeography of desert and semi-arid regions of the southwestern USA and adjacent Mexico. We inferred a Late Pliocene divergence between peninsular and continental lineages of Crotalus, followed by an Early Mid Pleistocene divergence across the continental divide within C. atrox. Within desert regions (Sonoran and Chihuahuan Deserts, Southern Plains, and Tamaulipan Plain) we observed population structure indicating isolation of populations in multiple Pleistocene refugia on either side of the continental divide, which we attempt to identify. Evidence of post-glacial population growth and range expansion was inferred, particularly in populations east of the continental divide. We observed clear evidence of (probably recent) gene Xow across the continental divide and secondary contact of haplotype lineages. This recent gene Xow appears to be particularly strong in the West-to-East direction. Our results also suggest that Crotalus tortugensis (Tortuga Island rattlesnake) and a population of ‘C. atrox’ inhabiting Santa Cruz Island (in the Gulf of California) previously suggested to be an unnamed species, are in fact deeply phylogeneti-cally nested within continental lineages of C. atrox. Accordingly, we suggest C. tortugensis and ‘C. atrox ’ from Santa Cruz Island be
Defining a monophyletic Cardinalini: A molecular perspective
, 2007
"... Within the New World nine-primaried oscine assemblage, feeding morphology and behavior have long been used as a guideline for assigning membership to subgroups. For example, birds with stout, conical bills capable of crushing heavy seeds have generally been placed within the tribe Cardinalini (cardi ..."
Abstract
- Add to MetaCart
Within the New World nine-primaried oscine assemblage, feeding morphology and behavior have long been used as a guideline for assigning membership to subgroups. For example, birds with stout, conical bills capable of crushing heavy seeds have generally been placed within the tribe Cardinalini (cardinal-grosbeaks). Many workers have tried to characterize this group more definitively, using a variety of morphological characters; however, the characters used often conflicted with one another. Previous molecular studies addressing the monophyly of Cardinalini have had only limited sampling within the group. In this study, we analyze mtDNA sequence data from all genera and 34 of the 42 Cardinalini species (sensu [Sibley, C.G., Monroe, B.L., 1990. Distribution and Taxonomy of the Birds of the World, Yale University Press, New Haven, CT]) to address the monophyly of the group and to reconstruct the most com-plete phylogeny of this tribe published to date. We found strong support for a redefined Cardinalini that now includes some members previously placed within Thraupini (tanagers; the genera Piranga, Habia, Chlorothraupis, and Amaurospiza) and some members previ-ously placed within the Parulini (wood-warblers; the genus Granatellus). In addition, some genera traditionally considered members of the Cardinalini are shown to have affinities with other groups (the genera Porphyrospiza, Parkerthraustes, and Saltator). Our redefined Cardinalini contains 48 species, six more than are listed in Sibley and Monroe’s (1990) taxonomy of the group. Within the nine-primaried oscine assemblage, the Cardinalini are more closely related to the Thraupini (tanagers) than they are to the Emberizini (sparrows), Paru-lini (wood-warblers), or Icterini (blackbirds), consistently forming a monophyletic group with Thraupini across all analyses. The recon-
te d
"... previously proposed phylogenetic hypotheses (Fig. 1) using fragments of two mitochondrial genes, cytochrome b (650 bp) and 12S rRNA (350 bp). Although these data consistently favored one of the four topologies (Topology I in Fig. 1), support values for the two critical nodes distin- ..."
Abstract
- Add to MetaCart
(Show Context)
previously proposed phylogenetic hypotheses (Fig. 1) using fragments of two mitochondrial genes, cytochrome b (650 bp) and 12S rRNA (350 bp). Although these data consistently favored one of the four topologies (Topology I in Fig. 1), support values for the two critical nodes distin-
Improving the Accuracy and Realism of Bayesian Phylogenetic Analyses
"... To my parents, Paul Joel Brown and Mary Ann Verkamp, for instilling in me an abiding love for learning, especially about the living world, and to my wife, Erin Grip Brown, whose patience and love are seemingly endless. Acknowledgements Throughout my academic career, I have been fortunate to have out ..."
Abstract
- Add to MetaCart
(Show Context)
To my parents, Paul Joel Brown and Mary Ann Verkamp, for instilling in me an abiding love for learning, especially about the living world, and to my wife, Erin Grip Brown, whose patience and love are seemingly endless. Acknowledgements Throughout my academic career, I have been fortunate to have outstanding mentors. As an undergraduate at Indiana University, the examples of Butch Brodie and Aneil Agrawal inspired me to pursue a career as an evolutionary biologist. At the University of Texas, David Hillis has been a wonderful guide through the ups and downs of graduate school. I would also like to thank the rest of my committee, Dan Bolnick, Randy Linder, Martha Smith, and, in particular, Jim Bull, for guidance and help whenever it was needed. My graduate education has also depended heavily on the kindness of fellow students. In particular, I owe a debt of gratitude to Alan Lemmon, Tracy Heath, and Derrick Zwickl. Two chapters of this dissertation are the result of collaborative work, to which others have contributed substantially. My co-author on Chapter 2 is Alan Lemmon, who
