Cephalopod orders

Vampyromorphida is an order of cephalopods comprising one known extant species (Vampyroteuthis infernalis) and many extinct taxa. Physically, they somewhat resemble octopuses (their closest relatives), but are often called vampire squids. Unlike octopuses, their eight arms are united by a web of skin, and two smaller cilia are also present. Properly speaking, the vampire squid does not possess cilia, but cirri (cilia-like projections). Unlike most cephalopods, which are high-energy hunters, the vampire squid has an extremely low metabolic rate. This adaptation means it requires less oxygen and

The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, Nautilus and Allonautilus, with six species. All told, between 22 and 34 families and 165 to 184 genera have been recognised, making this the largest order of the subclass Nautiloidea.

Spirulida is an order of cephalopods comprising one extant species (Spirula spirula) and several extinct taxa.

Ammonitida, or true ammonites, are an order of ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures.

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.