The project seeks to build a framework for evolutionary and systematic work in the rhabditid nematodes, a globally distributed group of free-living terrestrial roundworms. This project focuses on two species groups (clades), Eurhabditis and Pleiorhabditis. The primary objectives are to resolve evolutionary trees using multigene sequences; to elucidate the evolution of morphological characters in order to determine which features best diagnose different taxonomic groups; and to build an online database and key in order to make all this information freely and globally available.
Their diversity, significant role in organic decomposition, usefulness as bioindicators, the associations they make with other species, and the sheer abundance of species and individuals make rhabditid nematodes an important taxon, yet it is one of the neediest for systematic work and data-sharing resources. This project provides a systematic framework for a growing number of comparative and evolutionary studies of rhabditid development, behavior, reproduction, and genome structure and function, because the group includes the model genetic organism Caenorhabditis elegans and "satellite" models such as Pristionchus pacificus, Oscheius tipulae, and others. In the process of this project, graduate and undergraduate students and a postdoctoral researcher will be trained in rhabditid systematics, preventing the extinction of expertise in this field.
Intellectual merit Our specific research objectives and outcomes for this particular project were: To database all relevant information from published descriptions, types, and live material that bears on Rhabditina systematics, focusing first on a couple of monophyletic clades. Also, we were to describe new species accumulating in our collection and to train new people in rhabditid systematics. The outcomes and outputs included an online database, called RhabditinaDB (see: http://wormtails.bio.nyu.edu), which currently contains information from published descriptions for all rhabditid species, and includes phylogenetic, taxonomic, and morphological data for many other species. The database is essentially complete for genus Caenorhabditis. To increase taxon sampling and data to resolve relationships within Rhabditina, focusing especially on a couple of clades, in order to derive natural groups for taxonomy and to provide a framework for tracing character evolution, and to train students in molecular systematics. Outcomes included a well-resolved phylogeny for genus Caenorhabditis and a clade called Pleiorhabditis. Undergraduates were trained in DNA data collection and phylogenetic analysis. To compile a matrix of morphological characters, trace their evolution, and determine traits useful for taxon diagnoses. This character matrix was completed for all Caenorhabditis species, and is available via the RhabditinaDB database. We also designed and implemented a "PhenoBLAST" tool to allow users to search for species matching an input character profile. To build an online, interactive Key for Rhabditina, first focusing on a couple of clades. Due to lack of time, we did not get to this final, ambitious aim. However, the Key would depend on the matrix, which has been completed. Future research, if funded, would develop this key. Broader impact In the course of this work, we maintained and enhanced a major resource used by other scientists and educators for comparative biology, the NYU Rhabditid Collection, which includes a growing number of Rhabditina species and makes them available to scientists and educators. Enhancements included augmenting our live cryogenic preservation facility and adding new species. We published the results of the work will be published in well-regarded journals, including a paper by Kiontke et al., 2011, in BMC Evolutionary Biology. We trained a PhD student, a Professor at an undergraduate college and 2 undergraduate students in Rhabditina systematics and the art of alpha taxonomy (species description). Diverse undergraduates will be recruited and individually mentored in new research. Much of the taxonomic expertise in danger of being lost was retrieved and archived for the public in the freely accessible, online RhabditinaDB database.
