Triarthrus

Triarthrus Temporal range: Upper Ordovician PreꞒ Ꞓ O S D C P T J K Pg N
Triarthrus eatoni, specimen YPM 228
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	†Trilobita
Order:	†Ptychopariida
Family:	†Olenidae
Genus:	†Triarthrus Green, 1832
Species
T. beckii Green, 1832 (type species) = Paradoxides beckii, Calymene beckii T. billingsi Barrande, 1872 T. canadensis Smith, 1861 T. eatoni (Hall, 1838) = T. macastyensis T. glaber Billings, 1859 T. huguesensis Förste, 1924 T. latissimus Månsson, 1998 T. linnarssoni Torslund, 1940 T. rougensis Parks, 1921 T. sichuansis Lu & Chang, 1974 T. spinosus Billings, 1857

Triarthrus is a genus of Upper Ordovician ptychopariid trilobite found in New York, Ohio, Kentucky, and Indiana, eastern and northern Canada, China and Scandinavia. It is the last of the Olenid trilobites, a group which flourished in the Cambrian period. The specimens of T. eatoni that are found in the Beecher's Trilobite Bed, Rome, New York area are exquisitely preserved showing soft body parts in iron pyrite. Pyrite preservation has given scientists a rare opportunity to examine the gills, walking legs, antennae, digestive systems, and eggs of trilobites, which are rarely preserved. Triarthrus is therefore commonly used in science texts to illustrate trilobite anatomy and physiology.