perohlaidids

Perohlaidids are a family of extinct ammonoids, a diverse group of cephalopod molluscs that lived in the oceans from the Devonian to the Cretaceous periods. Perohlaidids are characterized by their distinctive shell morphology. Their shells typically exhibit a strong ribbing pattern, often with prominent axal or spiral ornamentation. The sutures, which are the lines where the shell chambers meet, are generally simple in perohlaidids, differentiating them from many other ammonoid lineages.

The Perohlaididae family is primarily known from the Permian period, with a notable presence in marine deposits from that era. Fossils of perohlaidids have been found in various parts of the world, indicating a wide geographic distribution during their existence. The exact ecological role of perohlaidids within Permian marine ecosystems is still a subject of research, but like other ammonoids, they are thought to have been nektonic predators, swimming freely in the water column.

The classification and evolutionary relationships of perohlaidids within the broader ammonoid phylogeny are based on detailed analysis of their shell structures and suture patterns. Their extinction, along with that of many other marine invertebrates, occurred during the Permian-Triassic extinction event, the most severe extinction event in Earth's history. Studying perohlaidids provides valuable insights into the evolution and diversity of ammonoids and the paleoenvironmental conditions of the Permian oceans.