DISSERTATION RESEARCH: Comparative Morphology of American and Australian Gastrotricha: the Muscular System as a Source of Taxonomic and Phylogenetic Characters

University Of New Hampshire, Durham NH

Investigators

Abstract

A grant has been awarded to Dr. Marianne Litvaitis and Mr. Richard Hochberg of the University of New Hampshire to conduct the first comparative anatomical analysis of gastrotrichs from Australia and North America. Gastrotrichs are a poorly known group of microscopic worms found throughout the world's oceans. Most knowledge of gastrotrich diversity is limited to species from the Northern Hemisphere, and much of this is exclusive to Europe. Anatomical knowledge of gastrotrichs from the United States and Australia remains in its infancy. Consequently, relationships between species from both continents are unknown. The principle objectives of this research are (1) to describe several new Australian gastrotrichs, (2) use characteristics of the body-wall and muscular system to determine relationships between Australian and American species, and (3) to place this information in an evolutionary context. Specimens will be analyzed using a combination of high-resolution light microscopy, scanning and transmission electron microscopy, and fluorescence microscopy. This research will highlight the use of novel characters to measure invertebrate biodiversity and determine evolutionary relationships among widely separated populations of gastrotrichs. As a study of the muscular system, it will also demonstrate how variation in muscle anatomy contributes to dispersal of microscopic fauna. Results from this research will provide much-needed taxonomic revisions of several new gastrotrichs and will yield insight into the biogeography and evolution of the Gastrotricha and the history of the Australian biota. With a greater anatomical knowledge of gastrotrichs, we will gain better insights into the ecological and evolutionary importance of this poorly known group of invertebrates.