|Devonian ≈ 400 ma|
Medium: 4.50-5.50 cm
Large: 5.50-6.50 cm
Precious Goniatites sp. These beautiful specimens are polished.
The Goniatítidos (Goniatitida), known by the common name of Goniatites, are an extinct order of shelled ammonoid cephalopods.
They originated at the beginning of the Devonian period, about 400 million years ago, from the most primitive ammonoids (Anarcestina). They were very abundant in seas around the world, surviving the Devonian mass extinction, finally going extinct in the Permian-Triassic, about 251.4 million years ago.
These mollusks were related to squids, belemnites, octopuses, cuttlefish and nautiloids.
The general structure of goniatites would have been similar to that of their ammonite cousins, being a free-swimming animal possessing a head with two well-developed eyes and arms (or tentacles).
A distinctive feature of goniatites are the sutures in their shell, which are simpler than later ammonoids, which showed increasingly complex suture patterns.
The piece you receive may differ slightly from the photo shown, as the fossils are natural and no piece is identical. The size is approximate.