Skip Navigation
  • UC Riverside
  • College of Natural and Agricultural Sciences

Dan Bumbarger

Dan Bumbarger

Ph.D., Ecology Evolution Systematics
Advisor: Dr. Jim Baldwin, Nematology
B.S. Biology 1997, Wright State University

Probolae are a complex manifestation of an extracellular matrix composed of several morphotypes of protein laminates. They surround the mouth opening of some members of the family Cephalobidae, and represent one of many types of cuticular modifications in nematodes. They are complex in terms of their external morphology, ultrastructure and diversity of form within the group. The intention of my work is to gain an understanding of the anatomy and morphogenesis of probolae in a single species of cephalobid nematode. This understanding will be extended to a comparative level by examining more specific aspects of morphogenesis in additional taxa within the framework of a molecular phylogeny. The research will consist of (1) light microscope observations of the life cycle in several taxa, (2) a three dimensional (3D) ultrastructural developmental series of the final molt produced via electron tomography, (3) an estimate of phylogenetic relationships done in collaboration with a molecular systematics lab and (4) additional comparative data on probolae produced by methods to be selected after the ultrastructural work. The primary justification is to provide a much needed description of anatomy in order to understand morphological characters used in phylogenetic analyses and for diagnostic purposes. This will directly address our most severe problems in the taxonomy of this group. This work will also provide a detailed description of the secretion and assembly of a highly specialized extracellular matrix (ECM), and may provide information useful for exploring collagen assembly in vivo. Finally, the potential of these nematodes as models for the study of evolutionary novelty will be explored.


Roush, S. A. and Bumbarger, D.J. 1998. Odonata of the Beaver Creek Wetlands, Greene County, Ohio: A preliminary survey. Ohio Journal of Science 98(3): 59-60.