Ophidiiformes are an order of ray-finned fish which include  cusk-eels, brotula and pearlfish. These bottom-dwelling marine fish are characterised by their long, slender bodies with both dorsal and anal fins. 

Ophidiiformes evolved during the Late Cretaceous. Ampheristus is the only described member of this order within the Eocene, London Clay and represents one of the earliest known members of this order.

This is an artistic reconstruction of an extinct Ampheristus toliapicus swimming along the silty/muddy sea floor during the Eocene.