The Bivalve Tree of Life: understanding the evolution of clams, mussels, oysters and their relatives
IQRA MUSHTAQ
Sophomore Anthropology/Biology double major at Loyola University
REU Mentors: Dr. Rüdiger Bieler (Curator, Zoology, Invertebrates) and Dr. Sid Staubach (Postdoctoral Fellow, Zoology, Invertebrates)
Symposium Presentation Title: Evolution of the Labial Palps and Gills within the Palaeoheterodonta (Mollusca: Bivalvia)
Symposium Presentation Abstract: Bivalves are easily recognizable animals that are known for their “two-shells” (bi-valves) connected by a hinge. They are most familiar to the public as clams, oysters, mussels, and scallops which may have come across their plate at a seafood restaurant. BivAToL 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 organisms. The BivAToL (Assembling the Bivalve Tree of Life) project aims to understand bivalve evolution by focusing on bivalve anatomy, morphology, and genetic makeup. Within the BivAToL project, my project for the summer was to reconstruct a plausible hypothesis of evolution for a specific bivalve organ system, the labial palps and gills. Labial palps and gills are very important organs in the Bivalvia as they are not only used for respiration, but are also essential for feeding and reproduction. The anatomical organization of gills is highly varied throughout the Bivalvia and an understanding of gill evolution is necessary in order to understand the evolution of bivalves in general. Using scanning electron microscopy, I investigated the labial palps and gills of seventeen species with a focus on the superorder Palaeoheterodonta and documented the most varied characters within a morphological data matrix using MorphoBank (www.morphobank.org). The morphological data matrix was used with molecular phylogenies in ancestral character state reconstruction to determine how the labial palps and gills evolved and how the labial palps and gills of ancestor species might have looked like and functioned. After reconstructing the evolution of the labial palps and gills, it is apparent that pearls are not the only prizes that can be extracted from bivalves.
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.
