Gravicalymene Trilobite from New York
Preserved Microconchid Epibiont
Order Phacopida, Family Calymenidae
Uncertain, Class Tentaculida
Time: Middle Ordovician
mm = 1 inch): Trilobite is 50 mm long by 33 mm wide Microconchid: 1.5
mm across on a 105 mm by 85 mm matrix
Lower Utica Shale, Herkimer County, New York
I have recently acquired a selection of Odovician and Devonian
trilobites from New York State, all of which are distinctive
in terms of preservation, unique preservational features, or
unusual heritage. This plate displays a huge Gravicalymene sp.
trilobite, the largest I have ever seen. What is even more unusual
is the presence of an epibiont known as a Microconchid. The
Microconchids are a group of small spirally-coliled encrusting
worm tubes known from the Upper Ordovician to the Middle Jurassic.
Some were previously known as the polychaete worm Sprirorbis.
Epibionts are organisms that live on the surface of another.
While some can be harmless, others can be parasitic. See my other
offerings for another unique example. In addition, this one comes
from the Utica Shale, a stratum not well known for the presence
fossil pictures to enlarge