Anomoeodus

Anomoeodus is an extinct genus of prehistoric marine ray-finned fish belonging to the family Pycnodontidae. This genus primarily lived during the mid-to-late Cretaceous period, ranging from the Albian to the very end of the Maastrichtian age, and possibly into the Danian. The first fossils of Anomoeodus were described by Louis Agassiz in 1833, although they were described under Pycnodus. Some studies have recovered it as a wastebasket taxon.

In the United States, fossil teeth of the widespread species A. phaseolus are colloquially referred to as "drum fish" teeth due to their close resemblance to those of modern drumfish. However, they are unrelated to actual drumfish, which only appeared during the Cenozoic.

Anomoeodus had a wide geographic distribution, with fossils found in France, Belgium, the Netherlands, Spain, Egypt, Uzbekistan, and the United States. Remains of the species A. subclavatus are known from the Campanian of the Kristianstad Basin in Sweden, making it one of the northernmost-occurring pycnodont taxa. This northwards migration may be associated with the warming temperatures of the time.

A. phaseolus teeth are known from the Main Fossiliferous Layer (MFL) of the Hornerstown Formation in New Jersey, which records a mass mortality event during the Cretaceous-Paleogene extinction event, likely just after the Chicxulub impact. As it is located slightly above the Cretaceous-Paleogene boundary, it is technically in the very earliest Danian. In any case, their presence indicates that Anomoeodus existed up until the Cretaceous/Paleocene boundary, and these fossils represent the latest records for the taxon. A single tooth is located slightly above the boundary, which may indicate that Anomoeodus survived further into the early Danian, but this tooth may have been reworked from earlier layers.

Like many members of its family, Anomoeodus had strong jaws and teeth adapted for crushing hard prey, making it mainly durophagous. Its diet is believed to have consisted primarily of crustaceans and mollusks.

Diagnostic features of this genus include teeth that are generally spherical, kidney-shaped, or elliptical, as well as the presence of four tooth rows in a jaw.

The following species are known:

The majority of these species are only known from isolated dental elements. Only a few species (A. angustus, A. willetti, A. subclavatus, A. pauciseriale) are known from more than just teeth.