Blanket octopus

[João Branquinho]

It's common name, Blanket octopus, comes from their large web which they use to glide through the ocean. Blanket octopuses are rarely observed, but when people see them they notice.

Not only do they look weird and shimmer with iridescence, they have an extreme degree of sexual dimorphism. The mature males are tiny compared to the females, just a few centimeters long. Tremoctopus are the most extreme example of sexual size-dimorphism in a non-microscopic animal. The weight of mature males is at least 1:10,000 of mature females. All of the blanket octopuses people typically see, which can be up to 2 meters long, are females.

If that wasn't cool enough, Blanket octopuses use the venomous tentacles of cnidarians such as Portuguese man o' war for defense.

Tremoctopus violaceus lives in the open ocean often in deep water (120-750 m) in the Mediterranean and the North and South Atlantic Ocean. The offspring are likely planktonic given the small size of the eggs. These octopuses may reproduce more than once but no one really knows much about their life history.

~ aloha ~

http://www.oceandefenderhawaii.com/

 

 

[octopus]

O Blanket octopus deve o seu nome, " polvo cobertor " , á membrana que une entre si as pernas dorsais.

Estes polvos contemplam 4 espécies:

Tremoctopus violaceus, T. gelatus, T. robsoni e T. gracilis.

 

O dimorfismo sexual é bastante acentuado, sendo que as fêmeas podem atingir os 2 metros de comprimento, enquanto os machos não ultrapassam os 20 cm. Outra diferença menos evidente, reside no número de filamentos branquiais, sendo de 7 a 13 nos machos e 8 a 16 nas fêmeas, consoante a espécie.

Sendo polvos pelágicos, não constroem ninho. A fêmea carrega entre 100.000 a 150.000 ovos, que através de filamentos calcários se fixam na base dos braços até à eclosão.

Outra particularidade interessante é o método de defesa. Sendo imunes ao veneno da medusa " caravela portuguesa ", ( Physalia physalis ), arrancam os tentáculos destas medusas e utilizam-nos como arma de defesa.

 

 

 

Fêmea juvenil com tentáculos de physalia.

 

 

 

Abraço,

Paulo