Pyritized Triarthrus Trilobite with Soft Tissue Preservation

Triarthrus eatoni

Trilobites Order Ptychopariida, Suborder Olenina, Family Olenidae, Subfamily Triarthrinae

Geological Time: Late Ordovician

Size: Trilobite is 18 mm long (25 mm with antennae)

Fossil Site: Lorraine Shale, Lewis County, New York


Triarthrus Trilobite with Legs & Antenna PreservedDescription: With only about a half dozen localities known, trilobites with soft tissue preservation are rare. A well-known site in the United States is Beecher’s Trilobite bed where examples of Triarthrus, Cryptolithus, and Cornuproetus are known. In 2005 a new location in Lewis County was discovered which will take its place in this select group as a site containing Triarthrus eatoni with preserved appendages. These trilobites were buried rapidly, resulting in an anxonic environment which allowed for infilling with fine-grained pyretic deposits that preserved the details seen here. The rich gold color is a striking contrast to the deep black matrix, making for a dramatic specimen available in very limited quantities. This fine example is preserved in laterodorsal aspect with both antennae and many biramous limbs in evidence. The darkened photo was taken with the sample immersed in toluene to heighten contrast. Such a specimen takes hours to prepare as a very fine grit must be used to preserve the delicate details as seen here. I am sure you will agree that the effort is well worth it.

click trilobite pictures to enlarge


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