Devonian ammonites

Clymeniida is an order of ammonoid cephalopods from the Upper Devonian characterized by having an unusual dorsal siphuncle. They measured about in diameter and are most common in Europe, North Africa, and South China but are known from North America (New York, Ohio, Oklahoma, and Utah) and Australia (New South Wales) as well.

Soliclymenia is a genus of ammonites from the Late Devonian. S. paradoxa has an unusual, triangularly-coiled shell. Additional genera of ammonites with triangular shells are Kamptoclymenia, Trigonoshumardites, and Trigonogastrioceras. Soliclymenia semiparadoxa, which is known only from the holotype, is semi-triangular, the innermost whorls being circular. Other species of this genus, including S. solarioides and S. recticostata, have a circularly-coiled shell.

Agoniatitida, also known as the Anarcestida, is the ancestral order within the cephalopod subclass Ammonoidea originating from bactritoid nautiloids, that lived in what would become Africa, Asia, Australia, Europe, and North America during the Devonian from about the lower boundary of Zlichovian stage (corresponding to late Pragian, after 409.1 mya) into Taghanic event during upper middle Givetian (between 385 and 384 mya), existing for approximately 25 million years.