An octopus is a soft-bodied, eight-limbed mollusc of the order Octopoda. The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth at the center point of the eight limbs. The soft body can radically alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.
Grimpoteuthis is a genus of pelagic cirrate (finned) octopods known as the dumbo octopuses. The name "dumbo" originates from their resemblance to the title character of Disney's 1941 film Dumbo, having a prominent ear-like fin which extends from the mantle above each eye. There are 17 species recognized in the genus. Prey include crustaceans, bivalves, worms and copepods. The average life span of various Grimpoteuthis species is 3 to 5 years.
Grimpoteuthis bathynectes is a deepwater species of so-called Dumbo octopus first described in 1990. So far only thirteen specimens have been recorded.
Grimpoteuthis abyssicola, commonly known as the red jellyhead, is a species of small deep-sea octopus known from two specimens. The holotype specimen was a female collected on the Lord Howe Rise, between 3154 and 3180 meters depth. A second specimen was collected on the continental slope of south-eastern Australia between 2821 and 2687 m depth. While the organism has not been formally assigned a vernacular name, it has been proposed to be referred to commonly as the angle-shelled dumbo octopus.
Grimpoteuthis boylei is a species of octopus known from only ten individuals.
Grimpoteuthis challengeri is a species of large octopus living in the abyssal zone.
Grimpoteuthis discoveryi is a small species of octopus known from more than 50 specimens. It was described in 2003, but specimens have been found as early as 1910. The type species was found at 49°35'N, 14°01'W.
Grimpoteuthis hippocrepium is a species of octopus. It is only known from one specimen found in 1904, which was poorly preserved. Some characteristics G. hippocrepium are unknown.
Grimpoteuthis innominata, commonly known as the small jellyhead, is a species of small, pelagic octopus described by Steve O'Shea in 1999 from two specimens, however several further specimens have since been identified. The genus Enigmateuthis was described to contain this species when described, but Martin Collins placed the species in the genus Grimpoteuthis due to uncertainty regarding the type specimen of Grimpoteuthis.
Grimpoteuthis meangensis is known from either one or two specimens, though the second may be of a completely different species. The first was damaged. Both were found by William Evans Hoyle within one year of each other, and no other animals of the species have been identified since 1886.
Grimpoteuthis pacifica is an octopus known from one badly damaged specimen. It is not completely described, and it is not easily separated from some other species of octopus. Nothing clearly differentiates G. pacifica from Grimpoteuthis hippocrepium except for its type locality.
Grimpoteuthis plena is known from only one specimen, which cannot be easily separated from other species of Grimpoteuthis in the Atlantic Ocean. The specimen was in poor condition. It's similar to Grimpoteuthis wuelkeri, and may be a junior specimen of Grimpoteuthis umbellata.
Grimpoteuthis tuftsi is an octopus known from seven specimens.
Grimpoteuthis umbellata, known from three specimens, is the type species of Grimpoteuthis.
Grimpoteuthis wuelkeri is a medium-sized octopus characterized from multiple specimens.
Opisthoteuthis agassizii, known as the Agassiz's flapjack octopus, is a lesser-known, deep-sea octopus first described in 1883 by Addison E. Verrill.
Opisthoteuthis borealis is a lesser-known species of octopus found near Greenland and Iceland, especially in the Davis Strait. The species was described from 9 specimens, and is one of the most recent Opisthoteuthis species described. Not much is known about it besides its anatomy and habitat.
Opisthoteuthis bruuni is a species of finned cirrate octopus found along the western coast of South America. Their tissue is almost jelly-like, and they have short, round bodies.
Opisthoteuths massyae is an octopus living in the eastern Atlantic Ocean.
Opisthoteuthis robsoni, also known as the deep-water umbrella octopus, is a deep-sea octopus living off New Zealand on the Chatham Rise. It has been found from 1,178–1,723 m (3,865–5,653 ft) below the surface. Not much is known about the octopus' habitat or life cycle, as only four specimens have been found. It occupies the benthic zone, or the seafloor and the water directly above it. O. robsoni eats large amphipods.
