Thursius pholidotus Traquair
This medium to large sized osteolepid is found at the start of the Rousay Subgroup. In the fish beds it is common and in the sediments indicating a shallow water condition only scales and plates of the head can be found. The scales look very much like those of Gyroptychius milleri.
It is a top predator but was probably eaten by the porolepiform Glyptolepis