Southern Marsh Clam
Polymesoda floridana (Conrad, 1846)
Family Cyrenidae (Marsh Clams and Asian Clams)
Polymesoda floridana typically lives in brackish tidal flats in protected creek areas. On Ohio Key in the Florida Keys, its habitat is a mangrove-fringed pond that frequently dries to cracking mud and isolated pools of high-salinity water. Polymesoda juveniles concentrate in moist cracks in the drying mud and are thus able to survive dry spells. Their shells are highly polychromic, showing a wide range of colors interiorly and exteriorly. The family Corbiculidae is known since the Triassic Period and is represented by ca. 8 living genera and ca. 100 species, distributed worldwide mainly in tropical and subtropical regions. Also in this family is the Asian Clam, Corbicula fluminea, a well-known and widely spread freshwater pest species in North America, introduced from Asia (probably for food) in the 1930s.
Evolution on the Half Shell...
The Assembling the Tree of Life: Bivalvia project (BivAToL) is a part of the Assembling the Tree of Life initiative, a large research effort sponsored by the National Science Foundation. Its goal is to reconstruct the evolutionary origins of all living things.
Jetsam & Flotsam
Some of the BivATOL team met in early May at the Mote Marine Laboratory’s Tropical Research Station at Summerland Key, FL for a combined collecting trip and coding workshop. Both activities are essential to our project’s goal of determining the phylogenetic relationships among the bivalve families.
After collection, many of the species’ visible and molecular characteristics must be compared and “coded,” after which the phylogenetic computer analyses will be run to produce the final “tree” from which a hypothesis of relationships can be made. Below is an example of a portion of such a phylogenetic tree. Families that are on nearby branches are more closely related to each other than those further away.