The 27 Best Deep-Sea Species: #7 Predatory Tunicates

#7: Megalodicopia hians (Phylum: Chordata, Class: Ascidiacea , Order: Phlebobranchia, Family: Octacnemidae)

This tunicate post is dedicated to Miriam. Those invertebrate sacs are one of our closest living invertebrate
relatives.  Let’s hear it for notochords and pharyngeal slits!

Most sea squirts are harmless little buggers that filter plankton out of the water column.  Water comes in through one siphon and out another (the in- and excurrent siphons). One group of sea squirts stands out-the family Octacnemidae.  The several genera in family have hypertrophied oral siphons (that’s just fun to say-hypertrophied oral siphon) that form two large lips creating an oral hood.  Anchored to the bottom, the wait until an unsuspecting small crustacean swims by. Then WAMM the large lips clamp close and its bye bye little arthropod.  Think Venus Fly trap but marine, deeper (200m to 3800m), and cooler.

Megalodicopia are also gender benders with both male and female bits.  Yeah simultaneous hermaphrodites!  If an individual cannot get any loving from a nearby predatory tunicate it gets busy with itself.

Feeding video here

Dr. M (1618 Posts)

Craig McClain is the Assistant Director of Science for the National Evolutionary Synthesis Center, created to facilitate research to address fundamental questions in evolutionary science. He has conducted deep-sea research for 11 years and published over 40 papers in the area. He has participated in dozens of expeditions taking him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses mainly on marine systems and particularly the biology of body size, biodiversity, and energy flow. He focuses often on deep-sea systems as a natural test of the consequences of energy limitation on biological systems. He is the author and chief editor of Deep-Sea News, a popular deep-sea themed blog, rated the number one ocean blog on the web and winner of numerous awards. Craig’s popular writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.





5 comments on “The 27 Best Deep-Sea Species: #7 Predatory Tunicates
  1. Gotta be careful – those tunicates, they will cut you!

    (fyi, blog back in a few – transitioning out of the davis womb…)

  2. Yay Dr. Byrnes! Trust me I know how difficult it is to be outside the protective cocoon of the UC-Davis campus. Its amazing the world outside of UCD can function at all.

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