Agassizodus is an extinct genus of eugeneodontholocephalan from the Carboniferous. It belongs to the family Helicoprionidae, which is sometimes called Agassizodontidae. Like other members of its family, it possessed a symphyseal tooth whorl, which was likely present at the tip of the lower jaw and associated with lateral crushing toothplates.[1] The type species, A. variabilis, was originally named Lophodus variabilis until the name "Lophodus" was determined to be preoccupied.[2]
A. variabilis was originally based on tooth fragments from the Pennsylvanian of Illinois, but the authors who named the genus (St. John and Worthen, 1875) also referred a massive jaw from Osage County, Kansas. The Osage jaw shared some similarities to tooth-whorls from the area, which were later described by Eastman (1902). Eastman concluded that the tooth whorls and jaw belonged to Campodus, so he renamed Agassizodus variabilis to Campodus variabilis.[2] Other authors disagree, arguing that the Eastman specimens and the Osage jaw represent neither Agassizodus or Campodus, but rather an entirely new genus.[3][4]
