Opisthoteuthis bruuni

Opisthoteuthis bruuni is a species of finned cirrate octopus found along the western coast of South America. Their tissue is almost jelly-like, and they have short, round bodies.[3][4]

Opisthoteuthis bruuni
Conservation status
Data Deficient  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Order:	Octopoda
Family:	Opisthoteuthidae
Genus:	Opisthoteuthis
Species:	O. bruuni
Binomial name
Opisthoteuthis bruuni Voss, 1982[2]
Synonyms
Grimpoteuthis bruuni[2]

The species was originally described from 16 young specimens collected off Antofagasta, Chile, at 250 to 360 m depth.[3] They were smaller than other known opisthoteuthids, reaching a maximum of 29 mm (1.1 in) mantle length. Even at this small, immature stage, the octopuses displayed sexual dimorphism (sex differences). The males had some enlarged suckers; three enormous suckers on each arm near the mouth were the most prominent, with a small cluster of enlarged suckers also present near the arm tips.[3] This sort of sexual dimorphism is also found in other opisthoteuthids.[5] Further specimens of O. bruuni have been collected from off Chile and Peru (between 5 and 33 degrees south), over a greater bathymetric range of 250 to 512 m depth. This later research also indicates a larger maximum body size (50 mm mantle length, 206 mm total length).[4]

The species is taken as bycatch in trawl fisheries due to its benthic occurrence, and thus may be threatened, but it is currently a data deficient species in the IUCN Red List of threatened species.[4]

When originally described, the extensively gelatinous body and overall form led to the suggestion that O. bruuni is potentially a mid-water or pelagic species.[3] This would be contrary to other Opisthoteuthis which are benthic.[6] However, later research on O. bruuni seems to suggest a benthic habit as material is routinely collected in bottom trawls.[4]

The species was originally placed in the genus Grimpoteuthis; however, it was placed in Opisthoteuthis after some re-evaluation. The classification of cirrate octopuses is regularly revised as scientists learn more about these deep-sea octopuses. Recent genetic and molecular testing, for example, confirmed O. bruuni as a member of the family Opisthoteuthidae.[7][4]

The octopus was named for Anton Bruun, a Danish ichthyologist.[3]