Caribbean Hammer Oyster
Malleus candeanus (d'Orbigny, 1853)
Family Malleidae (Hammer Oysters and Sponge Fingers)
Malleus candeanus lives nestled in crevices on reefs from Florida to Brazil, with only its ventralmost shell tips exposed. The larvae of this species are known to be both photonegative and geonegative, driving them to settle in dark overhanging portions of the reef. Other members of the family bury themselves in sponges. Hammer oysters derive their name from extensions on either side of the shells of larger species (less obvious in the Caribbean species), creating a T- or hammer-like shape. Malleids are known since the Cretaceous, and are distributed worldwide in warm seas.
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.