Permian Fossil Fish from Germany
Chordata, Class: Acanthodii, Order Acanthodiformes
Time: Early Permian (~290 million years
mm in length (along backbone) on 100 mm by 115 mm matrix
Rotliegendes, ( Red Beds), Rockenhausen, Germany
Acanthodians are jaw-bearing fish that still are the subject of
dispute over their systematic position because they have features
of both bony fish ( Osteichthyes) and cartilaginous fish (Chondrichthyes).
They possess highly advanced, spindle-shaped bodies thought to have
made them swift swimmers. The body was covered in small mosaic-like
scales. They possessed small teeth that were typically confined
lower jaw; some were toothless. The feature they all share in common
is the fact that massive spines formed of dentine support all fins
other than the caudal fins. Indeed, the name Acanthodii is derived
from the Greek word for spine.
oldest acanthodian lived during the late Ordovicain. They reached
their peak during the Devonian, and became extinct during the Great
Dying of the end-Permian extinction. This well-preserved example
is known as Acanthodes gracilis, the patronymic genus. The genus
died out in the lower Permian. As is typical, the most prominent
feature to be seen here are the diagnostic spines; the body contours
have been highlighted by the preparator to make viewing easier.
fossil pictures to enlarge