Osteoglossiformes, known as the Bony tongues, represent a group of fish which evolved in the Late Jurassic and still include just under 250 living species (most of which however are freshwater species) including the large Arapaima from the Amazon basin. These fish can grow large and have large, armour-like scales across their bodies.

Brychaetus muelleri is the only representative of this group which is found in the London Clay which is very distinctive for its robust enamel-tipped teeth. This would have been a marine predator rather than the modern freshwater relatives.

Photo of Arapaima gigas by Joshua J. Cotten on Unsplash