Dumbo octopuses

from Wikipedia, the free encyclopedia
Dumbo octopuses
Dumbo octopus (Grimpoteuthis sp.)

Dumbo octopus ( Grimpoteuthis sp.)

Systematics
Subclass : Octopus (coleoidea)
Superordinate : Eight-armed squid (Vampyropoda)
Order : Cirrus octopus (Cirroctopoda)
Subordination : Cirrina
Family : Disc umbrellas (Opisthoteuthidae)
Genre : Dumbo octopuses
Scientific name
Grimpoteuthis
Robson , 1932

Dumbo octopus ( Grimpoteuthis ; syn. Enigmatiteuthis ) is a genus of deep-sea octopus from the family of the disc umbrella (Opisthoteuthidae), about which not much is known to this day. The name Dumbo comes from the similarity with the title character from Disney's Dumbo (1941), because the Dumbo octopuses have large elephant-ear-like fins that protrude from the coat above the eye . Today 14 species are counted in the genus. They feed on crustaceans , clams , worms and copepods . The average lifespan of the different species is between three and five years.

features

Grimpoteuthis innominata ,
female, l. dorsal, r. ventral

Compared to the deep-sea octopus of the genus Opisthoteuthis , Dumbo octopuses are slightly less stocky in terms of the longitudinal axis of their bodies, and their elephant-ear-like fins are usually larger in relation to their body length, which averages 20 to 30 cm. The fins are about as long as the width of the coat. The body is supported with an inner, U- or W-shaped cartilage shell. The lateral legs of the shell are parallel to each other and do not taper at the tips. In order to be able to achieve optimal locomotion, the fins are also provided with a cartilage shell on the inside. The eyes are relatively large, circular, and more developed than other cephalopods. The arms are usually provided with two rows of cilia-like cirrus up to the tips , two per suction cup . It is believed that they are used to drive in smaller prey, as the octopus use them to create currents of water. The suction cups consist of a single field and are not toothed. Neither ink bag still Anallappen are available. The gills are in some ways like cuttlefish shaped hemispherical in other species. The radula , a chitin lamella in the throat of the cephalopod, which is used to chop up and transport food, is reduced to a row of teeth in the Dumbo octopus or is completely absent. Most of the time, prey is swallowed whole. The posterior salivary glands are very small or absent. The digestive gland is made up of a single lobe. The intestine is about the same length as the esophagus .

The largest previously discovered Dumbo octopus of a still unknown species was collected in June / July 2009 by Michael Vecchione from the National Systematics Laboratory (NSL), part of the Northeast Fisheries Science Center (NEFSC). He was 1.8 meters long and weighed 5.9 kilograms. On average, however, the body length is 20 to 30 centimeters. The average weight has not yet been determined.

Distribution and habitat

Among the species there are representatives of the benthic , the benthopelagial and the purely pelagial way of life.

Dumbo octopuses are among the rarest cephalopods, but it is believed that they are distributed worldwide and occur in the cold deep sea between 400 and 5,000 meters, but mainly between 3,000 and 4,000 meters. Individual specimens even live in abysses of 7,000 meters, which is known as the deepest habitat for octopuses today. Individual specimens have been discovered off the coast of Oregon , California , Martha's Vineyards , the Azores , the Philippines , Papua New Guinea , Australia and New Zealand .

Behavior and nutrition

Dumbo octopuses have a peculiar swimming behavior. They beat back and forth with their ear-like fins to move. They can use their arms to steer in any direction or use them to crawl on the sea floor. Furthermore, passive umbrella-like drifting was observed. In addition, the arms are used for hunting, laying eggs, exploring the environment and more.

When hunting, the cuttlefish hover above the seabed and catch poly bristles , pelagial copepods, woodlice , amphipods and other crustaceans by pouncing on them and devouring them whole.

Endangerment and Predators

Dumbo octopuses are not exposed to any direct human hazard, as they mainly reside at depths above 3,000 meters. Natural predators include sharks , killer whales , tuna and larger cephalopods .

Reproduction

In contrast to many species of cephalopods, the males of the genus Grimpoteuthis neither have a hectocotylus , an arm whose anatomy has reproductive features, nor enlarged suckers, which are also used for reproduction. You have a kind of appendage on one arm that surrounds a penis. The internal reproductive organs show significant differences among the species, which have not yet been fully explored. The function of the individual organs is also still controversial. This transfers the ejaculated sperm packages into the female's mantle cavity . Compared to those of other cephalopods, the eggs are quite large and covered with a tough secretion that is secreted by the fallopian glands and hardens in salt water.

The females carry multiple eggs at different stages of maturity, suggesting that they do not have a fixed period of reproduction. It is believed that at any given time, the females may be able to distribute the sperm to the eggs based on the prevailing environmental conditions. The fertilized eggs are deposited at great depths under small stones or shells, but they can also be carried on the upper arms until a safe place is found. As with other cephalopods, neither the eggs are guarded nor the offspring raised, as the young can defend themselves or flee after they hatch.

Species list

Below are the 14 species known today, which belong to the genus Grimpoteuthis :

Grimpoteuthis umbellata ,
type species of the genus

It is possible that Grimpoteuthis wuelkeri and G. umbellata or G. plena are the same species.

Cirroteuthis umbellata was first described by the malacologist Paul Fischer in the Journal de conchyliologie in 1883. Guy Coburn Robson named this species in 1932 in the second volume of his work A Monograph of the Recent Cephalopoda along with his first description of the genus Grimpoteuthis as its type species .

Web links

Commons : Dumbo Octopus ( Grimpoteuthis )  - Collection of images, videos, and audio files

Individual evidence

  1. ↑ a b c d e f g h i j k Finned Deep-sea Octopuses, Grimpoteuthis spp. MarineBio.org, accessed March 7, 2018 .
  2. ↑ Dumbo octopuses. BBC, October 2014, accessed March 7, 2018 .
  3. ↑ a b c d e f Richard E. Young, M. Vecchione: Grimpoteuthis Robson 1932. Tree of Life Web Project, February 27, 2016, accessed March 7, 2018 .
  4. ↑ Shelley Dawicki: NOAA Researchers, Ships Participate in Census of Marine Life's Decade of Discovery. Northeast Fisheries Science Center, November 23, 2009; accessed March 7, 2018 .
  5. ↑ Dumbo Octopus. Aquarium of the Pacific, accessed March 7, 2018 .
  6. ↑ Martin A. Collins, R. Villanueva: Taxonomy, ecology and behavior of the cirrate octopods . In: Robin N. Gibson et al. (Ed.): Oceanography and Marine Biology . Vol. 44. London 2006, ISBN 978-1-4200-0639-1 , pp. 277-322 ( online [PDF]).
  7. ↑ Grimpoteuthis, The Dumbo Octopus. Ocean Portal, accessed March 7, 2018 .
  8. ↑ Martin A. Collins: The genus Grimpoteuthis (Octopoda: Grimpoteuthidae) in the north-east Atlantic, with descriptions of three new species . In: Zoological Journal of the Linnean Society . tape 139 , no. 1 , September 1, 2003, p. 93-127 , doi : 10.1046 / j.1096-3642.2003.00074.x .
  9. ^ Paul H. Fischer : Note préliminaire sur une nouvelle espèce du genre Cirroteuthis . In: Journal de conchyliologie . Series 3, volume 23 , no. 4 , October 1, 1883, p. 402-404 .
  10. ↑ Guy Coburn Robson: A Monograph of the recent Cephalopoda . tape 2 : The Octopoda (excluding the Octopodinae) . London 1932, p. 81-89, 116-173 .