Museum Triarthrus Trilobite with Preserved Soft Tissue

Description: 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 pyritic 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. 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. When you consider that some 98% of all specimens found fall in the 8mm to 10 mm range this example is most uncommon. This is one of three I was able to obtain at this year’s Tucson fossil show. All three are unique examples of the exquisite preservation for which this site has become world famous.