''Eledone gaucha'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

octopus An octopus ( : octopuses or octopodes, see below for variants) 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, cuttle ...

from the southern

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

. It is a predator of fish, crabs, lobsters and molluscs. This octopus is a member of the genus ''

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

'' and belongs to the family

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

. It was distinguished from a similar species, ''

Eledone massyae ''Eledone massyae'', the combed octopus, is a small benthic octopus found off the Atlantic coasts of southern South America, particularly Argentina and southern Brazil. Description The body is rounded and slightly flattened dorso-ventrally. Th ...

''. ''Eledone gaucha'' is smaller in size than '' E. massyae'' and has a smaller mantle and head.

Description

''Eledone gaucha'' possesses a firm, thin, ovoid and elongated mantle. It is separated from the head by a small constriction. The body is smooth and papillae can be found on the dorsal mantle and on the head. The head is narrower than the mantle and the eyes are protruding. The syphon is long, W-shaped and free from its front half. The arms are long and thin. The dorsal arms are notably longer than the other arms and the arms from the males are longer than those of the females.The suckers are small, well separated and deeply anchored in the arms. On the arms of females, suckers are regrouped on the tip of the arm. On the second half of the first right arm, the number of suckers vary between 17 and 23. Males possess heteromorphic arms and some arms with hectocotyl thaht have modified papillae or suckers. One arm possesses an hectocotyl. The color varies from brown to nearly white dorsally to nearly always white ventrally. Females have a various size ranging from 14 to 55 mm and males range from 14 to 47 mm. The main sources of food for ''E. gaucha'' are microcrustaceans such as

Gammaridae Gammaridae is a family of amphipods. In North America they are included among the folk taxonomic category of " scuds", and otherwise gammarids is usually used as a common name. They have a wide distribution, centered on Eurasia, and are eury ...

Caprellidae Caprellidae is a family of amphipods commonly known as skeleton shrimps. Their common name denotes the threadlike slender body which allows them to virtually disappear among the fine filaments of seaweed, hydroids and bryozoans. They are sometime ...

, of

isopods Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, an ...

and macro crustaceans such as decapods of the orders Brachyura and

Anomura Anomura (sometimes Anomala) is a group of Decapoda, decapod crustaceans, including hermit crabs and others. Although the names of many anomurans include the word ''crab'', all true crabs are in the sister group to the Anomura, the Brachyura (the ...

. The species can also feed on

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

s, bony fish and

mollusks Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

Distribution

''Eledone gaucha'' is found along the coasts of Southern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, between Cavo Frio and Chui. For now, it has never been found further south than the coasts of Brazil.

Habitat

''Eledone gaucha'' is found at moderate depth on muddy or sandy soils. During the reproductive period, individuals move to rocky soils overlooking gentle slopes. This habitat is common with ''

''.

Reproduction

Females become sexually mature when they are older and taller than males. They can reproduce when they are not fully mature and store sperm at the apex of ovary filaments. No seasonality in mating could be observed. It is also assumed that cohorts of individuals overlap during the year, each with a reproductive cycle estimated to be sub-annual.

References

{{DEFAULTSORT:Eledone gaucha gaucha Molluscs described in 1988