Triarthrus eatoni (HALL, 1838)
Whetstone Gulf Formation, Lewis County, New York
An amazing and remarkable discovery made in the mid 2000's brought to light one of the most mysterious and talked about trilobite localities known from upstate New York, Beecher's Pyrite Trilobite Beds. Having been closed to collectors for over a century, many of Beecher's original sites had been lost and over taken back by the forest, these trilobites come from this recent discovery made nearby by a local collector.
The remarkably well-preserved fossils are about 1 - 3 cm long, and suggest the animal was intact with a shell along with the delicate parts of limbs and antennae protruding from the shell. The fossil was preserved in pyrite and was examined using X-Ray and CT Scan techniques.
From the middle Ordovician, these fossils are estimated to be about 450 million years old.
Several theories as to why these fossil trilobites preserved so delicately are made known when you look closely at the specimens themselves, they are not made up of sheets of pyrite, but rather thousands of small orbs. These "orbs" show a body form of an ancient sulfur bacteria that may have either (1) lived symbiotically with the trilobite in life or (2) covered the body of the animal once deceased and once covered quickly in mud, preserving the living shape of the trilobite in the soft mud.