Grimpoteuthis is a genus of pelagic umbrella octopuses 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 13 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.
|Scientific classification |
14, see text
Most species of Grimpoteuthis live at depths of at least 3,000 to 4,000 metres (9,800 to 13,100 ft) with some living up to 7,000 metres (23,000 ft) below sea level, which is the deepest of any known octopus. They are some of the rarest of the Octopoda species though they occur worldwide including in the waters of New Zealand, Australia, Monterey Bay, Oregon, Philippines, Martha's Vineyard, Papua New Guinea and Azores. The largest dumbo octopus ever recorded was 1.8 metres (5.9 ft) in length and weighed 5.9 kilograms (13 lb). The average size for most species is 20–30 centimetres (7.9–12 in) in length. The average weight is still undetermined.
- Grimpoteuthis abyssicola O'Shea, 1999, red jellyhead
- Grimpoteuthis bathynectes Voss & Pearcy, 1990
- Grimpoteuthis boylei Collins, 2003
- Grimpoteuthis challengeri Collins, 2003
- Grimpoteuthis discoveryi Collins, 2003
- Grimpoteuthis hippocrepium (Hoyle, 1904)
- Grimpoteuthis innominata (O'Shea, 1999), small jellyhead
- Grimpoteuthis meangensis (Hoyle, 1885)
- Grimpoteuthis megaptera (Verrill, 1885)
- Grimpoteuthis pacifica (Hoyle, 1885)
- Grimpoteuthis plena (Verrill, 1885)
- Grimpoteuthis tuftsi Voss & Pearcy, 1990
- Grimpoteuthis umbellata (P. Fischer, 1884)
- Grimpoteuthis wuelkeri (Grimpe, 1920) – possibly same as G. umbellata or G. plena
Several species formerly classified in this genus were moved to other opisthoteuthid genera.
Range and habitat
Species of Grimpoteuthis are assumed to have a worldwide distribution, living in the cold, abyssal depths ranging from 1000 to 4,800 metres (13,000 ft). Specimens have been found off the coast of Oregon, the Philippines, Martha's Vineyard, the Azores, New Zealand, Australia, California, Gulf of Mexico, Papua, and New Guinea. Dumbo octopuses are among the deepest living octopuses known.
Species of Grimpoteuthis face few direct threats from humans, living at depths of 1,000 meters (3,300 ft) and below. Natural predators include sharks and predatory cephalopods. The Grimpoteuthis does not have an ink sack and therefore, they change colors and size due to their chromatophore cells that helps them protect themselves from predators. Some color changes can be red, white, pink, brown, or they become an invisible color so that they can blend in with the ocean floor.
Movement, characteristics and food supply
The genus has a distinct habit of swimming. Whilst it appears that the large fins on the side of the head are propelling the creature, it is actually a siphon, pushing water out the back, creating propulsion. The fins are in fact primarily used for stabilization and steering. Movement of the arms can be used to help the animal move in any direction. The arms permit the animal to crawl along the seafloor, to capture prey, lay eggs, explore, etc. Dumbos hover above the sea floor, searching for polychaete worms, pelagic copepods, isopods, amphipods, and other crustaceans for food. Prey is captured by pouncing on the target, which then is swallowed whole. It is also interesting to know that contrast to other octopuses, dumbo octopuses do not produce ink. This makes sense considering the fact that their habitat is a deep, dark place in the ocean. Instead of ink sacs, dumbo octopuses take advantage of a strand-like structure on their suckers to help them sense the surrounding environment as well as looking for food.
Females have no distinct period for breeding. Females carry multiple eggs in various stages of maturation, suggesting that they have no optimal breeding period. Male octopuses have a separate protuberance on one of their arms that carries an encapsulated sperm packet to the female. It is hypothesized that the female can then distribute this sperm to the eggs at any given time based on environmental conditions. The females lay the eggs under small rocks or on shells in the deep ocean or can even carry them on her arms, by tucking the eggs behind the wide webbing, until she finds a safe place that would provide them with the best fitness. As with other octopuses, females do not invest any further time in the young after they hatch because once they are born they are able to defend themselves. Females can be distinguished from males by body type. Females have a much more prevalent gelatinous body type with size being more width than length, having 1.5 to 2 time more short arms. Other differences include females having broadly U-shaped shells, larger eyes, and gills with six lamellae.
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- Dumbo Octopus video at BBC