Mysella planulata (Stimpson, 1851)
Family Lasaeidae (Lasaeid Clams)
Living lasaeids, like this Mysella planulata from Indian Key Fill in the Florida Keys, have a mobile probing foot on which they can actively crawl like snails. The family Lasaeidae is known since the Cretaceous Period and is represented by ca. 70 living genera and an undetermined number of species, distributed worldwide. Certain features (such as reduction of the gills, brooding larvae, and the creeping foot) have been considered secondary simplification associated with pedomorphosis (retention of juvenile characters in reproductive adults).
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.