Wikipedia
Bathynotus
Bathynotus is a genus of trilobites of the family Bathynotidae. Its fossils have been found in the paleocontinents Laurentia (specifically in what are now Nevada and Vermont), Gondwana (in South China and South-Australia), and - doubtfully - Siberia. It is characterized by a very wide axis in the thorax and an enlarged 11th segment that bears a long, backwardly directed spine on each side. Additionally, the 12th and 13th segments are narrow and fuse with the edge of the spine of the 11th segment.