Pyritized Triarthrus Trilobite with Preserved Soft Tissue

Ventral Preparation

Triarthrus eatoni

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

Geological Time: Late Ordovician

Size: Trilobite is 22 mm long with 5 mm antennae

Fossil Site: Lorraine Shale, Lewis County, New York

Triarthrus eatoniDescription: 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 anoxic 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 ventral mode with walking legs and biramous appendages in evidence, along with a fine pair of antennae. The photos were 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.

click trilobite pictures to enlarge

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