DISSERTATION RESEARCH: Phylogenetic systematics, lineage diversification, and niche evolution in spinetails (Furnariidae, Aves)

Louisiana State University, Baton Rouge LA

Investigators

Abstract

Determining the how species are created is key to understanding the origins and maintenance of biodiversity across the planet. This project tackles this issue by focusing on a small set of very similar tropical birds called "spinetails", which are unusual because they appear to have developed new species at an incredibly fast rate. If this rapid speciation is indeed the case, study of spinetails will likely reveal novel insights about how new species come about. Investigators will use genetic techniques and cutting-edge statistical analyses to determine the evolutionary history of spinetails. The study will foster international partnerships through sharing of genetic samples and collaborating on complicated analyses of huge genetic datasets. The study will also provide research opportunities for undergraduates interested in learning how to apply bioinformatics and statistical programming to answer fundamental questions in ecology and evolutionary biology. Results of this study will help resolve long-standing taxonomic confusion about spinetails and provide a clearer picture of South American biodiversity -- a goal of both science and conservation. Specifically, the investigators will test two alternative hypotheses of speciation. Both hypotheses rely on geographic isolation as a key requirement and explore the ecological context in which populations become isolated. On the one hand, if two populations of the same species occur in different environments it may cause to them to diverge ecologically due to local adaptation. Alternatively, small environmental differences may exist within a species' distribution due to conserved ecological preferences. If this distribution is divided by a region outside the species' ecological preference, such as mountains for a lowland species, dispersal will be greatly restricted. These hypotheses will be tested at multiple evolutionary scales. Across Furnariidae, there is a positive relationship between the rate of ecological divergence and speciation. Importantly, the arboreal spinetails (genus Cranioleuca) exhibit rates of ecological divergence and speciation far exceeding those found in other groups in the family. Both observations support the hypothesis that ecological divergence is associated with speciation, but to test these hypotheses a densely sampled phylogeny is needed. This study will reconstruct the evolutionary relationships of the arboreal spinetails using genomic scale genetic datasets. Investigators will then employ detailed comparative analyses to determine if speciation in this group is associated with ecological divergence or conservatism.