Education
- B.S. Biology University of California, Riverside 2003
Research Focus
I am interested in the phylogeny and systematics of phylum Nematoda. My primary focus is on the evolution of feeding structures, specifically the hypodermic needle like stomatostylet in Tylenchida, a group including most plant parasitic nematodes. To test hypotheses of homology, characters of the stomatostylet and associated structures are mapped on independent phylogenetic trees that resolve the relationship of the Tylenchida to Cephalobina outgroups, which are characterized by an open stoma. Subtleties of feeding structure morphology can be difficult to interpret by light microscopy alone and even static TEM thin sections. Adequately assessing homologies and transformations of these complex characters requires complete 3D TEM reconstruction, which has revealed that in spite of their superficial divergence many elements of feeding apparati, such as those pertaining to underlying epidermal tissue, are highly conserved between parasites and outgroups. Findings are being integrated with additional morphological, developmental, and molecular characters for a broad representation of taxa within and outside the Tylenchida to build character matrices that are maximally informative and reliable. A better resolved phylogeny of Tylenchida and outgroups (including Aphelenchoidoidea, a closely related group of stylet bearing nematodes) based on independent, molecular characters is necessary to detect patterns of parallel or convergent evolution. Consequently, trees based currently on protein and 18S and 28S D2-D3 rRNA gene sequence data are being more thoroughly developed. Research efforts are being incorporated into the larger context of achieving morphological and molecular resolution for Tylenchida and outgroups as part of the Nematode Tree of Life.
Selected Publications
- Baldwin, J. G., Ragsdale, E. J., and Bumbarger, D. 2004. Revised hypotheses for phylogenetic homology of the stomatostylet in tylenchid nematodes. Nematology 6: 623-632