West Indian Awning Clam
Solemya occidentalis Deshayes, 1857
Family Solemyidae (Awning Clams)
Solemya extends its foot, revealing the “stellate disk” of the sole used in creating its U- or Y-shaped burrow in the mud. This 5 mm (0.2 in) species ranges from Florida, throughout the Caribbean and Gulf of Mexico, and to Brazil. It is commonly found in the stomach of the Bonefish (Albula vulpes). Awning clams thrive in anaerobic sediments, and are thus common around sewage outfalls and mangrove channels. Most species have endosymbiotic bacteria upon which they depend in part for nutrition. Their shells are weakly calcified and can bend and contract in many directions during burrowing. They are known to swim in the laboratory by jetting water out of the mantle cavity, but are not known to do so in nature. They are also notably water repellant (that is, they float in the laboratory dish) due to a lipoprotein secreted by oil glands in the mantle. This may provide greater ability to shed sticky mud in their typical habitat.
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.