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Bivalves in Time and Space (BiTS): Clams as tools to understand macroevolution

2011 REU Project:

This study is part of a collaborative effort (see also www.bivatol.org/BiTS/) to develop bivalves as a model clade for macroevolutionary studies. By integrating molecular, morphological and paleontological datasets, BiTS aims to test methods of molecular clock dating, ancestral state reconstruction and historical biogeography, as well as to detect spatial and temporal trends in evolution.

BiTS researchers at the Field Museum concentrate on the morphological and paleontological components of the project, investigating the evolution of numerous shell and anatomical features in two of the commonest bivalve lineages - venus clams and cockles.

Research methods and techniques: REU participants in the project will receive an introduction to bivalve morphology and systematics, with particular focus on shell characters - i.e., those that preserve well in fossils. They will prepare specimens, document diagnostic characters with optical and scanning electron microscopy, build and analyze phylogenetic trees, and gain experience with relevant literature research and collection management techniques.

Curator/Advisors: Dr. Rüdiger Bieler, Zoology/Invertebrates, in collaboration with postdoctoral fellow Dr. André Sartori.


REU Intern: KATHERINE ANDERSON
Ecology and Evolutionary Biology major
University of Michigan, Ann Arbor

Symposium Presentation Title: Diversity of Venus clams: building an online resource for species identification

Symposium Presentation Abstract: Venerids, commonly known as Venus clams, are the most diverse family of marine bivalves, with over 500 extant species.  They are found on every continent except Antarctica, and many are edible, commercially collected and cultured, comprising an important food source worldwide.  Despite their prevalence and economic importance, there is still no freely accessible, online catalogue available to aid in recognition of venerid species.  Species identification is crucial not only for economic reasons, but also for conserving biodiversity and ensuring accuracy in scientific studies.  An online catalogue consisting of individual species pages with detailed morphological descriptions and high quality photographs is being built in order to provide a resource that is both complete and available for anyone to use.  Specimens from the collections of the Field Museum of Natural History were identified to species level using primary and secondary literature.  Following identification, the morphology of the shell of each species was thoroughly described based on characteristics of all specimens available.  Descriptions include details of overall shape and coloration, as well as features important for bivalve taxonomy, such as the morphology of the hinge teeth, lunule, escutcheon and ligament.   In order to aid in identification, differences among similar species that may be commonly confused were also noted on each species page.  High quality photographs of the dorsal view, external and internal views of one valve, and the hinge plates of both valves were taken of a representative specimen of each species.  Species pages were published on eBivalvia, a collaborative database for information about bivalves, which shares its contents with the Encyclopedia of Life.  In addition to species pages, genus pages were also created containing descriptions of characteristics shared by all species within a genus.  At this time, over 100 species of venerids have been described and photographed.  The species pages may become more comprehensive in the future, as information such as habitat and distribution is appended.  The online catalogue not only documents the diversity of Venus clams, but also provides an accurate and accessible resource for species identification that can be utilized by researchers, students and shell collectors, as well as conservation agencies and fisheries.