Belantsea is a genus of extinct petalodontiform cartilaginous fish that lived during the Early Carboniferous. Fossils of Belantsea montana have been found in the Bear Gulch Limestone lagerstätte, and are preserved in exceptional detail. Its body was tall and compressed, with large pectoral fins and a small tail fin. This body plan suggests a lifestyle similar to modern reef fish, and it is thought that Belantsea was adapted for life in reefs of sponges. Its few, large, triangular teeth suggest a diet of hard-shelled marine invertebrates. The genus contains two species, B. montana and B. occidentalis.