Benthoctopus levis
Encyclopedia
Benthoctopus levis is a species of octopus
in the Octopodidae
family. It was first described by William Evans Hoyle
in 1885 in an article in the Annals and Magazine of Natural History detailing the new species of octopus found on the HMS Challenger
as part of the Challenger expedition
; the type specimen was retrieved from the Southern Ocean
. The species is found in subantarctic
waters in the Southern Ocean, particularly surrounding Heard Island and Kerguelen Island, but specimens comparable to B. levis have also been found at the Antarctic Peninsula
.
It is known to inhabit shallow depths of between 21 and 404 m (68.9 and 1,325.5 ft). It is predatory, living and feeding in the benthic zone
, where it feeds heavily on brittle stars. In a study in which the stomach contents of 70 specimens were examined, around 50 were shown to have fed only on brittle stars. A study on the reproductive strategies of coleoid cephalopod
s concluded that while "a simultaneous terminal spawning strategy is most likely" for B. levis, "the egg-length frequency graphs and multivariate analysis also suggest a greater variation in egg-lengths which could lead to spawning over an extended period". The study collected five female B. levis specimens from the Southern Ocean. They weighed from 16 to 219 g (0.564383393681791 to 7.7 oz) and the mantle
length was from 34 to 58 mm (1.3 to 2.3 in).
B. levis is similar in appearance to another species in the same genus, Benthoctopus rigbyae. B. rigbyae was first described in 2009 based on specimens found in Antarctic trawling surveys near the Antarctic Peninsula, and, while similar in appearance, differs from B. levis in its arm length, the depth of its interdigital webbing
and specific details of its hectocotylus
. Further, the species is found in slightly deeper waters, having been recorded at depths of between 250 and 600 m (820.2 and 1,968.5 ft).
Octopus
The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...
in the Octopodidae
Octopodidae
Octopodidae is the family containing the majority of known octopus species.-Subfamilies and species:*Basal genus Vulcanoctopus*Genus incertae sedis Histoctopus*Subfamily Bathypolypodinae**Genus Bathypolypus**Genus Benthoctopus...
family. It was first described by William Evans Hoyle
William Evans Hoyle
Dr William Evans Hoyle was the first director of the National Museum of Wales between 1909 and 1926. Trained as a medical anatomist, Hoyle is most famous for his monographic studies on cephalopods from major exploring expeditions of his era including the Challenger, the Albatross, the British...
in 1885 in an article in the Annals and Magazine of Natural History detailing the new species of octopus found on the HMS Challenger
HMS Challenger (1858)
HMS Challenger was a steam-assisted Royal Navy Pearl-class corvette launched on 13 February 1858 at the Woolwich Dockyard. She was the flagship of the Australia Station between 1866 and 1870....
as part of the Challenger expedition
Challenger expedition
The Challenger expedition of 1872–76 was a scientific exercise that made many discoveries to lay the foundation of oceanography. The expedition was named after the mother vessel, HMS Challenger....
; the type specimen was retrieved from the Southern Ocean
Southern Ocean
The Southern Ocean comprises the southernmost waters of the World Ocean, generally taken to be south of 60°S latitude and encircling Antarctica. It is usually regarded as the fourth-largest of the five principal oceanic divisions...
. The species is found in subantarctic
Subantarctic
The Subantarctic is a region in the southern hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° – 60° south of the Equator. The subantarctic region includes many islands in the southern parts of the Indian Ocean, Atlantic Ocean and...
waters in the Southern Ocean, particularly surrounding Heard Island and Kerguelen Island, but specimens comparable to B. levis have also been found at the Antarctic Peninsula
Antarctic Peninsula
The Antarctic Peninsula is the northernmost part of the mainland of Antarctica. It extends from a line between Cape Adams and a point on the mainland south of Eklund Islands....
.
It is known to inhabit shallow depths of between 21 and 404 m (68.9 and 1,325.5 ft). It is predatory, living and feeding in the benthic zone
Benthic zone
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. They generally live in close relationship with the substrate bottom; many such...
, where it feeds heavily on brittle stars. In a study in which the stomach contents of 70 specimens were examined, around 50 were shown to have fed only on brittle stars. A study on the reproductive strategies of coleoid cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s concluded that while "a simultaneous terminal spawning strategy is most likely" for B. levis, "the egg-length frequency graphs and multivariate analysis also suggest a greater variation in egg-lengths which could lead to spawning over an extended period". The study collected five female B. levis specimens from the Southern Ocean. They weighed from 16 to 219 g (0.564383393681791 to 7.7 oz) and the mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
length was from 34 to 58 mm (1.3 to 2.3 in).
B. levis is similar in appearance to another species in the same genus, Benthoctopus rigbyae. B. rigbyae was first described in 2009 based on specimens found in Antarctic trawling surveys near the Antarctic Peninsula, and, while similar in appearance, differs from B. levis in its arm length, the depth of its interdigital webbing
Interdigital webbing
Interdigital webbing is the presence of membranes of skin between the digits. Normally in mammals, webbing is present in the embryo but resorbed later in development, but in various mammal species it occasionally persists in adulthood...
and specific details of its hectocotylus
Hectocotylus
A hectocotylus is one of the arms of the male of most kinds of cephalopods that is modified in various ways to effect the fertilization of the female's eggs. It is a specialized, extended muscular hydrostat used to store spermatophores, the male gametophore...
. Further, the species is found in slightly deeper waters, having been recorded at depths of between 250 and 600 m (820.2 and 1,968.5 ft).