is a fish that lived in the Late Cretaceous and whose fossils are common in the Upper Cretaceous Upper chalk in the Kent region of England. Fossils of this fish are usually preserved in chalk rocks, which were formed in marine environments, especially those sediments rich in calcareous microfossils and mudcrystals. These fish fossils are of great significance for paleontologists to study ancient marine ecosystems and fish evolution. Not only does it provide us with information about the morphology and structure of this fish, it also helps scientists understand the paleoenvironmental conditions in which they lived. By studying these fossils, scientists can reconstruct ancient marine ecosystems

Ray finned fish, a major evolutionary branch of bony fish, is characterized by its fins being fan-shaped membranes supported by spoke shaped bony/keratinous spines, which differ from the paddle shaped fleshy fins supported by multi jointed appendicular bones in meat finned fish or by cartilage columns in cartilaginous fish.

The Eusthenopteron lived in the Devonian period 400 million years ago. It is a freshwater fish that feeds on aquatic animals.