Habitat, nutrition
Kingdom: Animalia
Phylum: Mollusca Class: Cephalopoda Order: Octopoda Family: Octopodidae Genus: Vulcanoctopus Species: V. hydrothermalis |
Vulcanoctopus (just has the one species currently) is the only species of octopus known live around hydrothermal vents[1][2][3]. They inhabit the East Pacific Rise, at about 2600-2650m below the surface on the sea floor[2][3]. They have eyes, but they are greatly reduced in fuction, seeming to lack an iris and showing no response to the light from submersibles[1][3]. So they crawl, primarily using touch and smell[3] to hunt crabs (such as Bythograea thermydron[1][3]) and engulf swarms of amphipods with the webbing between its tentacles near hydrothermal vent openings[1]. Swimming has only been observed as an escape manouver[3].
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Morphology, reproduction
V. hydrothermalis' body lacks any kind of pigment, and appears semi-translucent[1][3]. It is a small muscular[3] octopus, with a mantle up to 56 mm, and weighing up to 45 g[2]. Suckers are present in rows of two along the tentacles, which range from 1.5-4.3 times the mantle length. One of the right tentacles is specialized for depositing spermatophores, packets of (5 to 114, normally distributed[2]) gametes, into the females mantle cavity[1][2]. However, none of the 17 specimens collected by Gonzalez et al were females[2]. This enigma might suggest spacial separation among sexes[2]. One octopus, of the 25 observed by Rocha et al, is suspected to be a female[3].
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Left to right:
feel-feeding on the ocean floor; ambushing a swarm of crustaceans; probable mating, with mounting and spermatophore deposit a a distance
feel-feeding on the ocean floor; ambushing a swarm of crustaceans; probable mating, with mounting and spermatophore deposit a a distance
References
[1]http://scienceblogs.com/deepseanews/2007/04/11/from-the-desk-of-zelnio-vulcan/
[2]Gonzalez, A. F.; Guerra, A., Rocha, F., & Briand, P. (2002). 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.
[2]Gonzalez, A. F.; Guerra, A., Rocha, F., & Briand, P. (2002). 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.