Category Archives: cnidarians

Friday Fellow: Deep-sea marr

by Piter Kehoma Boll

Looking like some sort of tribal mystic rattle, our newest Friday Fellow comes from the deep waters in the northern hemisphere. Its scientific name is Marrus orthocanna, and I adapted a common name as “deep-sea marr”. I think it sounds cool.

A magic rattle form the deep sea. Photo by Kevin Raskoff

A magic rattle from the deep sea. Photo by Kevin Raskoff.

The deep-sea marr is a siphonophore cnidarian, and as all siphonophores, it is a colonial organism rather than a single individual. It is composed by several specialized organisms (zooids) linked together by a long “stem” and unable to live independently. It is a free-swimming organism, swiming in a pulsative way through the dark deep sea waters.

At the front or upper side of the colony is the pneumatophore, a gas-filled float that is the primordial organism in the colony, the one that originated directly from the embryo. After it, there are several bell-shaped translucent organisms, the nectophores, which are specialized in locomotion, making the colony move by contractions. The last part of the body, the siphosome, contains a series of different zooids, including individuals specialized to capture prey, to digest food and to reproduce.

The deep-sea marr is found mainly in Arctic waters, but sometimes occurs more southwards, down to the Mediterranean Sea. It may grow to several meters in length and its diet most likely includes small crustaceans. It is a weird, but certainly beautiful creature.

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References:

EOL –  Encyclopedia of Life: Marrus orthocanna. Available at: < http://eol.org/pages/1005745 >. Access on April 21, 2016.

Wikipedia. Marrus orthocanna. Available at: <https://en.wikipedia.org/wiki/Marrus_orthocanna >. Access on April 21, 2016.

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Filed under cnidarians, Friday Fellow, Zoology