''Eledone massyae'', the combed octopus, is a small benthic

octopus An octopus (: octopuses or octopodes) is a soft-bodied, eight-limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like oth ...

found off the Atlantic coasts of southern South America, particularly

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

and southern

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Description

The body is rounded and slightly flattened dorso-ventrally. The head is narrower than the mantle and separated by a slight constriction. The opening in the mantle is very large and the arms are the same length. The suckers are small, separated from one another and deeply anchored in the arm. The third arm possesses a

hypocotyl The hypocotyl (short for "hypocotyledonous stem", meaning "below seed leaf") is the stem of a germinating seedling, found below the cotyledons (seed leaves) and above the radicle (root). Eudicots As the plant embryo grows at germination, it send ...

in the male individuals. Also in males, other arms have suckers that decrease in number until the tip of the arm. After the last sucker are two ranges of papillae that diverge on the sides. On female individuals, the arms are not modified. Females have a variable size ranging from 24 to 91 mm and males vary between 22 and 80 mm. ''Eledone massyae'' feeds mostly on macro

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s such as

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

s from the family

Portunidae Portunidae is a family of crabs which contains the swimming crabs. Its members include well-known shoreline crabs such as the blue crab (''Callinectes sapidus'') and velvet crab ('' Necora puber''). Description Portunid crabs are characterised b ...

as well as

polychaete Polychaeta () is a paraphyletic class of generally marine Annelid, annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called c ...

s and mullusks.

Distribution

''Eledone massyae'' is found seasonally along the continental shelf of

Rio de Janeiro Rio de Janeiro, or simply Rio, is the capital of the Rio de Janeiro (state), state of Rio de Janeiro. It is the List of cities in Brazil by population, second-most-populous city in Brazil (after São Paulo) and the Largest cities in the America ...

. Its distribution ranges from Rio de Janeiro to the Peninsula Valdez in

Habitat and ecology

It lives in sandy and muddy areas of the middle and outer

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

of the southwestern

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

between 30° and 34°S, mainly in waters off Argentina and southern Brazil. In these areas it appears to be

sympatric In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

with a scarcer cogener, ''

Eledone gaucha ''Eledone gaucha'' is a species of octopus from the southern Atlantic Ocean. It is a predator of fish, crabs, lobsters and molluscs. This octopus is a member of the genus ''Eledone'' and belongs to the family Eledonidae. It was distinguished f ...

''. The species is found on the bottom of slopes. During spring and summer, it is found in cold waters of maximum 18 degrees Celsius and around 60 meters deep. In autumn, it is found rather close to continental shelves with a maximum temperature of 21 degrees Celsius while in winter, it is found close to continental shelves with subantarctic cold water influences.

Reproduction

The lifespan of ''E. massyae'' is approximately around two years. Females die after a single spawning that takes place in autumn around November. The eggs hatch around March. It is supposed that they are attached to a solid substrate such as rocks. Juveniles appear in summer on the continental shelf where they grow and reach sexual maturity in spring or summer of their second year. Like other species of

Eledone ''Eledone'' is a genus of octopuses forming the only genus in the family (biology), family Eledonidae. It is mainly distributed in the northern and southern Atlantic Ocean, with one species, ''Eledone palari, E. palari'', described from the south ...

, female ''Eledone massyae'' are able to store sperm when they are not sexually mature in order to use it when they reach sexual maturity. The sperm could be stored for three months between copulation and spawning. The process of maturation of ''E. massyae'' is different regarding each sex. Females become sexually mature when the ovary enlarges as a result of yolk production. This enlargement occurs late in the life of the individual. In males, the process of sexual maturation is complex and begins early in the individual's life. It is strongly correlated with body size.

References

{{Taxonbar, from=Q3201092 massyae Cephalopods described in 1964