Overview

Comprehensive Description

Color: In situ, white, eyes black.
  • GONZÁLEZ A.F., GUERRA A., PASCUAL S. & P. BRIAND (1998) Cah. Biol. Mar. 39: 169-184.

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This benthic species has characters that represent either adaptations to the deep-sea (absence of ink sac, loss of the anal flaps, eye without iris and optic chiasma) or to a hydrothermal vent habitat (eyes are covered by a thin semitranslucent skin, high concentrations of metals and presence of amoebocytes clots in the venous system and in the renal sacs). It inhabits an isolated extreme environment among aggregations of tubeworms Riftia pachyptila, Alvinellidae polychaetes or mussels, very close to the chimneys (2-10°C); also observed on the pillow lava at several meters from the active areas. No predation over these species was observed. Octopuses forage on bathypelagic amphipods, apparently targeting their attacks based on contact with the swarming amphipods (e.g. Halice hesmonectes). Some male specimens were parasitised by Genesis vulcanoctopusi, a species of cholidynid harpacticoid (copepod).
  • GONZÁLEZ A.F., GUERRA A., PASCUAL S. & P. BRIAND (1998) Cah. Biol. Mar. 39: 169-184.

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Distribution

East Pacific Rise: collected at 13°N (Fig. 2) and 21°S (Fig. 1); observed at 23°S (Fig. 3).
  • GONZÁLEZ A.F., GUERRA A., PASCUAL S. & P. BRIAND (1998) Cah. Biol. Mar. 39: 169-184.

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Physical Description

Morphology

Body semi-translucent with a muscular consistency; mantle pear-shaped and posteriorly mitre-like; presence of a large white body (which covers the eye, the optic nerves and the optic lobe), an inflated black bulb (dark swelling), in proximal third of the intestine, a crop, and a multilobulate digestive gland; absence of an ink sac. Arms 1.5-4.3 times mantle length. Two rows of suckers on each arm. Arm formula typically 1.2.4.3 or 2.1.4.3. No enlarged suckers. Maximum depth of the largest sector of the web about 22% of the longest arm. Gills with 7-8 lamellae per demibranch. Right arm III hectocotylized (HA 1.5-2.1 times mantle length) in males. Ligula short (8-10% of HA), lance-shaped and without transverse ridges. Calamus represents 30-50% of the ligula length in fully mature specimens. Spermatophore length 70-125% of mantle length. Only one female of 35 mm mantle length was collected; external morphology similar to male. Finger-like oocytes (80) ranging from 0.15- 4 mm maximum length.
  • GONZÁLEZ A.F., GUERRA A., PASCUAL S. & P. BRIAND (1998) Cah. Biol. Mar. 39: 169-184.

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Size

Up to 56 mm mantle length, 235 mm total length and 45 g body weight.
  • GONZÁLEZ A.F., GUERRA A., PASCUAL S. & P. BRIAND (1998) Cah. Biol. Mar. 39: 169-184.

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Ecology

Habitat

Depth range based on 6 specimens in 1 taxon.
Water temperature and chemistry ranges based on 6 samples.

Environmental ranges
  Depth range (m): 2521 - 2632.5
  Temperature range (°C): 1.822 - 1.831
  Nitrate (umol/L): 40.639 - 41.112
  Salinity (PPS): 34.668 - 34.669
  Oxygen (ml/l): 2.514 - 2.542
  Phosphate (umol/l): 2.809 - 2.814
  Silicate (umol/l): 159.968 - 160.712

Graphical representation

Depth range (m): 2521 - 2632.5

Temperature range (°C): 1.822 - 1.831

Nitrate (umol/L): 40.639 - 41.112

Salinity (PPS): 34.668 - 34.669

Oxygen (ml/l): 2.514 - 2.542

Phosphate (umol/l): 2.809 - 2.814

Silicate (umol/l): 159.968 - 160.712
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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Wikipedia

Vulcanoctopus hydrothermalis

Vulcanoctopus hydrothermalis is a small benthic octopus endemic to hydrothermal vents.[1]

It is the only known species of the genus Vulcanoctopus.

Habitat[edit]

Vulcanoctopus hydrothermalis lives along the East Pacific Rise, the border of the Pacific, Cocos, and Nazca Plates. It is often found near colonies of giant tube worms.

Description[edit]

The morphology of V. hydrothermalis shows some unusual traits for an octopus, due to adaptations selected for in the deep sea, such as the lack of an ink sac. Its dorsal arms are longer than the ventral arms. These feature biserial suckers. Overall, it has a mean total length of 184 mm (7.2 in).[2]

Behavior[edit]

The ratio of recovered individuals is skewed towards males, indicating fewer females or spacial segregation by sex. Its primary defense reaction is to freeze in place, then if needed, the secondary defense involves pushing away from the bottom then drifting back down. V. hydrothermalis uses its front arms (I dorsal and II dorsolateral) for feeling its way around and detecting and catching prey, while the back arms (III ventrolateral and IV ventral) support its weight and move the octopus forward. This species has not been observed to use jet propulsion.[3]

Prey[edit]

Its confirmed prey include the amphipod Halice hesmonectes, and crabs are thought to be one of their primary food sources.[1]

References[edit]

  1. ^ a b CR McClain (11 April 2007). "From The Desk of Zelnio: Vulcanoctopus hydrothermalis". Deep Sea News. Retrieved 4 January 2012. 
  2. ^ Gonzalez, A. F.; Guerra, A.; Rocha, F.; Briand, P. "Morphological variation in males of Vulcanoctopus hydrothermalis (Mollusca, Cephalopoda)". Bulletin of marine science. 
  3. ^ Rocha, F.; Gonzalez, A. F.; Segonzac, M.; Guerra, A. (2002). "Behavioural observations of the cephalopod Vulcanoctopus hydrothermalis". Cah. Biol. Mar. pp. 299–302. Retrieved 8 October 2013. 
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