Invertebrate Spotlight: Larvaceans


Mucus house of a Larvacean

Invertebrate Spotlight: Larvaceans

By Michelle Marraffini

Invertebrate Zoology Lab

Today in the Marine Invertebrate Zoology we learned about one of the most interesting marine animals.  Larvaceans (Class Larvacean) are unique animals in the phylum Chordata along with their close relatives sea-squirts (Class Ascidiacea) and slightly more distant relatives humans (Subphylum Vertebrata).   These chordates retain their tadpool larva form and excrete a mucus house from specialized cells located on their head.  This house starts off as a small balloon like structure, the tadpole Larvacean whips its body to inflate the balloon with water, then when it is big enough the animal crawls inside, and whips its tail to continue to inflate the house.  Larvaceans will also eat with the help of their house which also contains screens set up to filter water, water is then further filtered by the animal so that it can eat bacteria sized particles.

A schematic of a larvacean in its house with the screens and showing water current flow. Photo Credit:

They live in this house until the screens become clogged and then they swim out of it start to make a new one.  They discard their old house with sinks to the ocean floor as marine snow.  Marine snow is considered a big source of nutrients to the deep sea, to learn more about how larvaceans contribute to marine snow check out MBARI’s website.

Larvacean photo, screens shown in red tint, white folds are more filtering tools, and the animal itself is in the center of it’s house. Photo Credit: Arctic Exploration 2002, Per Flood, NOAA/OER

This entry was posted in Cool Creatures, Michelle Marraffini, Tales from the Classroom and tagged , . Bookmark the permalink.

1 Response to Invertebrate Spotlight: Larvaceans

  1. Wayne Thompson says:

    Super cool!! Are these easily studied and/or kept in aquaria?


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