Trilobite Tuesday: Triarthrus


By Joseph “PaleoJoe” Kchodl

Trilobites are an extinct form of arthropod related to insects, crabs, crayfish and horseshoe crabs. These creatures are called trilobite due to the three distinct “lobes” running vertically through the body section.

Arguably one of the most important discoveries in trilobite science is the PYRITIZED TRIARTHRUS of New York State.

TRIARTHRUS (Hall 1838) are often preserved in iron pyrite in what is now called “Beecher’s Bed”. It is an Ordovician location discovered by Charles Beecher in Central New York. It is unique because soft body tissues are found preserved. Due to anoxic conditions, (without or low oxygen), antennae, legs and gill branches can be seen leading Beecher to recreate what the trilobites may have looked like in life. Recently work being done in those deposits has yielded evidence of tiny eggs within the body structure of some of the trilobites.

Generally around one half inch long, these are truly some magnificent trilobites. The pictured trilobite is the view of a ventral image, the underside of the trilobite.

About the columnist: Joseph “PaleoJoe” Kchodl is a paleontologist, educator, veteran, author, fossil dig organizer/guide, business owner, husband, father, and grandfather, and fossil fanatic. For decades, he’s spent hours in classrooms around the Midwestern United States and beyond, speaking to school children about fossils and fossil hunting. Visit his site to purchase fossils, contact PaleoJoe, visit

Plus, learn more about PaleoJoe and his daughter PaleoJen and their paleontology exploration partnership in an the article “Fueling a Passion for Paleontology”.  


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