Glossus humanus (Linnaeus, 1758)
Family Glossidae (Heart Cockles)
Glossus is an unusual and relatively rare species, with a thick solid shell up to 10 cm (3.9 in) in length. The yellow-white shell is usually covered by a dark red-brown periostracum. It occurs in deep water from Norway south to the Iberian Peninsula and into the Mediterranean Sea. It lives in mud or sandy mud leaving just the lower margin of the shell and its short siphons exposed. This single specimen was dredged from mud in the 100 m (328 ft) deep channel between the islands of Arran and Bute, off western Scotland.
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.