Campyloprion

Campyloprion is an extinct genus of large shark-like eugenodont fish. Two species of Campyloprion are known, C. annectans from Texas and New Mexico in United States and C. ivanovi from Russia. The fossils date to the Gzhelian stage, approximately 303.4–298.9 million years ago. There is a small gap in age between the latest Edestus and the first Campyloprion, which suggests that Campyloprion might have evolved to fit into an ecological niche left vacant by the extinction of Edestus. The fact that Campyloprion is older than Helicoprion suggests, but does not prove, that it is a direct ancestor of Helicoprion.

Description
Campyloprion teeth resemble those of Helicoprion, but the tooth whorl has an open spiral shape, more loosely coiled than that of Helicoprion. The size of its teeth indicate a length of up to 9 m (30 ft), which would make it one of the largest animals of the Carboniferous period.