Amphistium

Amphistium

• Monte Bolca ( northern Italy)
• Paris Basin

Amphistium is a fossil genus of the order of the flatfish ( Pleuronectiformes ). Fossils of the genus were first found later in the fossil deposit Monte Bolca near the Italian city of Verona, also in the Paris Basin.

Features

Amphistium has a roundish - oval, strongly laterally flattened body and sting rays in dorsal and anal fin. Dorsal and anal fins extend arcuately over almost the entire body length. The latter has 21 to 22 soft rays. Its outer edge is convex. The caudal fin is long, undivided and rounded. The eyes are small, the snout pointed.

The orbital region of the skull is asymmetrical, one eye is moved in adult animals toward the back line, but it has not yet been exceeded. This can vary from individual to individual, be the case on both the right and on the left side of the head. Amphistium probably lived predatory.

System

Amphistium was assigned by Agassiz first the mackerel -like ( Scombridae ), a suborder of Perciformes ( Perciformes ). This assignment has been widely recognized as maintaining the deformation of the skull for a post-mortem deformation. It was not until 2002, the U.S. paleontologist Jack Sepkoski Amphistium as home group representative in the order of the flatfish, after it was recognized that the asymmetry of the skull occurs only in larger animals and in specimens of the same size is always the same.

Species

• Amphistium altum, Paris Basin
• Amphistium paradoxum, Monte Bolca