Maximites

Maximites is a genus of Late Carboniferous ammonoids. Adult specimens were the smallest known ammonoids, only at about 1 cm in diameter of shells. Fossils are found in various Late Carboniferous marine strata in North America. Maximites is the sole genus of Maximitidae, one of two families of the Superfamily Pseudohaloritoidea, an important subgroup of the order Goniatitida.