Amphioctopus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of octopus

Octopus

The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...

es comprising around 16 species.

Description

Members of the genus Amphioctopus reside in tropical and subtropical waters. These octopuses are found primarily in the Pacific

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 and Indian Ocean

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

s but representatives can also be found in the Atlantic

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

. They are characterized by arms that are about 2 or 3 times their mantle

Mantle (mollusc)

The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...

 length with deep lateral webs and very shallow dorsal webs. This genus can be further divided into two subgroups, one group with ocellate

Eyespot (mimicry)

An eyespot is an eye-like marking. They are found on butterflies, reptiles, birds and fish. In members of the Felidae family , the white circular markings on the backs of the ears are termed ocelli, and they are functionally similar to eyespots in other animals.Eyespots may be a form of...

 octopuses, the other with non-ocellate octopuses.

Taxonomic status

Historically, members of this genus were placed within the genus Octopus, but recognized as forming a distinct group and referred to as the Octopus aegina species complex. The genus was originally described by Fischer in 1882. He assigned to it the already described species, Octopus membranaceus (Quoy and Gaimard, 1832), as the type species

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 (not to be confused with Enteroctopus membranaceus (Rochebrune and Mabille, 1889), the original types species of the genus Enteroctopus

Giant octopus

Enteroctopus is an octopus genus, many of whose members are sometimes known as giant octopuses.- Description :Enteroctopus is a genus of generally temperate octopuses. Members of the genus Enteroctopus are characterized by their large size and are often known as the giant octopuses...

). Robson in his review of octopus taxonomy in 1929 regarded Amphioctopus membranaceus as a nomen dubium

Nomen dubium

In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...

, referring it to his newly named "aegina species complex", a group of octopuses forming a distinct constellation characterized by Octopus aegina. The genus Amphioctopus was subsequently considered invalid. In 2002, Gleadall suggested that the aegina species group represents a distinct genus with Amphioctopus being the senior name. In 2004, Gleadall resurrected the genus Schizoctopus and assigned Octopus fangsiao as the type species. In 2005, Huffard and Hochberg, arguing that Robson's designation of Octopus membranaceus as a nomen dubium was premature and considering it a valid name, resurrected the genus name Amphioctopus for the Octopus aegina species complex. Huffard and Hochberg also found Schizoctopus to be a junior synonym for Amphioctopus.

Species

• Amphioctopus aegina
• Amphioctopus arenicola
• Amphioctopus burryi
• Amphioctopus exannulatus
• Amphioctopus fangsiao
  Amphioctopus fangsiao
  Amphioctopus fangsiao is a species of octopus, a cephalopod belonging to the genus Amphioctopus.-Further reading:*Furuya, H. Three new species of dicyemid Mesozoans from Amphioctopus fangsiao , with comments on the Occurrence Patterns of Dicyemids. Zoological Science 23, 105 - 119, -External links:*...
  
  
• Amphioctopus granulatus *
• Amphioctopus kagoshimensis
• Amphioctopus marginatus
  Veined Octopus
  Amphioctopus marginatus, also known as the coconut octopus and veined octopus, is a medium-sized cephalopod belonging to the genus Amphioctopus. It is found in tropical waters of the western Pacific Ocean...
  
  
• Amphioctopus membranaceus *
• Amphioctopus mototi
• Amphioctopus neglectus
• Amphioctopus polyzenia
• Amphioctopus rex
• Amphioctopus robsoni
• Amphioctopus siamensis
• Amphioctopus varunae

Species marked with an asterisk (*) remain unresolved.