octopodiform

Octopodiformes, or octopodiforms, is a taxonomic clade within the class Cephalopoda that includes the octopuses (order Octopoda) and the vampire squid (order Vampyromorphida). In many classifications, Octopodiformes is treated as a superorder or clade within the subclass Coleoidea and is considered the sister group to Decabrachia, which comprises the squids and cuttlefishes. The name combines Greek roots for “octopus” and the suffix “-iform,” meaning “in the form of an octopus.”

Extant diversity within Octopodiformes is limited to two lineages: the diverse Octopoda and the Vampyromorphida, represented today solely by Vampyroteuthis infernalis, the vampire squid, a deep-sea species with adaptations for low-oxygen environments.

Anatomically, octopodiform cephalopods share a soft, flexible, shell-less body and a highly developed nervous system relative to many other invertebrates. Octopuses are typically characterized by eight arms with suckers and a capacity for complex behavior, while the vampire squid resembles octopods in body plan but possesses distinctive deep-sea adaptations, including a mantle veil and specialized sensory features suited to their habitat.

Ecology and life history vary across the group. Octopuses occupy a wide range of habitats—from shallow coastal zones to deep-sea environments—and are often solitary and predatory. The vampire squid inhabits cold, dark, low-oxygen waters of the deep ocean and feeds on detritus and small particulates, rather than large prey.

Taxonomic status within cephalopods continues to be refined as molecular studies illuminate relationships among lineages. The Octopodiformes clade underscores the evolutionary connection between the intelligent, eight-armed octopuses and the enigmatic vampire squid.