Pyritized Eldredgeops Trilobite
Preserved Sensory Bristles
Order Phacopida, Family Phacopidae
Time: Middle Devonian
mm = 1 inch): Trilobite is 25 mm (curve measure); Matrix: 90 mm by
Windom Shale, Hamilton Group, Moscow Formation, Erie County, New York
Here is a remarkable example of preservation: a totally pyritized
Eldredgeops rana trilobite. Its rich golden color has led me
to coin the term Midas Touch when referring to these specimens.
This is a recent find, and one that I do not believe has ever
been offered before. Pyrite is typically prone to the oxidative
degradation termed “pyrite disease”. Examples of
these have been subjected to forcing conditions with no ill effects.
Nevertheless as a precaution they have been given a coating of
an archival quality material which is employed in the conservation
of ancient artifacts. While all found to date are somewhat small,
they make up for lack of size in tremendous eye appeal. This
one is preserved enrolled in left lateral view. What is most
unusual about this one is the presence of what must have been
sensory bristles preserved on the pleurae. These have not been
documented before, particularly not in a pyritized specimen.
Sensory papillae have been theorized before without any actual
visible proof. Some trilobites such as the Russian Ordovician
as asaphids are known to possess pits on the exoskeleton, and
some believe they might have held papillae which served a sensory
function just like the vibrissae (whiskers) of the family cat.
I include here a negative photo to make them more apparent. The
discoverer and preparatory has also seen these is other trilobites,
and Bob Carroll has told me in the past that Cyphaspis carrolli
and Kettneraspis williamsi also sport these features but they
never survive the preparation process. Some day I will get to
Bob’s to document them.
trilobite pictures to enlarge