Comparative Gill and Labial Palp Morphology (Mollusca: Bivalvia)
EMILY LAUREN RUDICK
Sophomore Biology major at Temple University, College of Science and Technology
REU Mentors: Dr. Rüdiger Bieler (Curator, Zoology, Invertebrates) and Dr. Ana Glavinic (Postdoctoral Fellow, Zoology, Invertebrates)
Symposium Presentation Title: Comparative Gill and Labial Palp Morphology (Mollusca: Bivalvia)
Symposium Presentation Abstract: Bivalves, with 20,000-30,000 living species, are the second largest class of mollusks next to gastropods. They are aquatic, bilaterally symmetrical and characterized by a laterally compressed body enclosed in a bivalved shell. In addition, they play important ecological roles in marine and freshwater ecosystems during the process of filter feeding, and economic roles in fisheries and health sciences. Funded by the National Science Foundation, the BivATOL (Assembling the Bivalve Tree of Life) Project aims to reconstruct the evolutionary history of bivalves using molecular and morphological approaches. In our study, we used scanning electron microscopy to investigate the anatomical structures of gills and labial palps. Besides the shell and stomach, gills and palps are one of the most important character complexes for phylogenies based on morphological characters. They are also a highly functional character system in regard to feeding, respiration, sensory function and breeding. The Bivalvia are divided in two major clades, the Protobranchia, which retain a number of plesiomorphic characters, and the Autolamellibranchiata. Here, we will compare the morphological characteristics of gills and labial palps in seventeen different species and eight different orders of bivalves (two protobranch and six autolamellibranch orders) to determine character polarity. We will test if the assumed monophyly of each major clade and order is supported by the gill and labial palp morphology. Additionally, our phylogeny consisting of 41 morphological characters will be compared with bivalve phylogenies derived from other independent character suites in order to postulate preliminary hypotheses about the evolution of specific characters.
Original Project Title: The Bivalve Tree of Life -- understanding the Evolution of Clams, Mussels, Oysters and their Relatives
Original Project Description: This project (see also www.BivAToL.org) is a part of the Assembling the Tree of Life initiative, a large research effort sponsored by the National Science Foundation to reconstruct the evolutionary origins of all living things. The BivAToL effort uses hundreds of selected target species from around the world and studies their morphology, anatomy, ultrastructure, and genetic makeup.
Research methods and techniques: REU participants in the project will receive an introduction to bivalve morphology and systematics. Participants will dissect and prepare specimens for microscopy, document diagnostic characters with optical and scanning microscopy, and gain experience with relevant literature research and collection management techniques. Time permitting, various histological techniques (in Field Museum’s histology laboratory) and 3-D computer reconstruction will become part of the training experience.
