The Beautiful Sea Butterfly!
Sea butterflies, also known as Thecosomata or flapping snails, are a taxonomic suborder of small pelagic swimming sea snails. They belong to the most abundant group of snails, Opisthobranchia. These snails float and swim freely in the water and are carried through currents.
Because of it being a free-swimmer this has led to a lot of adaptations in their body. The shell and gill have disappeared in several families. Their foot has taken the form of two wing-like lobes, or parapodia, which propel this animal by little flapping movements. They are rather difficult to see because the shell (when present) is mostly colorless, very fragile and usually less than a centimeter in length. Even though their shell is tiny and basically transparent it is still calcareous. Their shells are bilaterally symmetric and vary widely in shape; coiled, triangular, needle-like, and globulous. They are holoplanktonic; which means they spend their whole life in planktonic form rather than just being planktonic in a larval stage.
Form and Function:
Very little is known about the sea butterflies and their habits but it is known that they have a particular way of feeding. Sometimes they just float through the water ventral-side up with the currents. They are usually passive plankton feeders but at times they can be real hunters. They are mostly herbivorous entangling plankton in a mucous web up to 5 cm wide (most of the times this web is bigger than the animal itself.) When threatened they release these nets and swim downward.
Sea butterflies are hermaphroditic meaning that they need to animals to sexually reproduce. Not much else is none except that when the reproduction is finished they release a free-floating, gelatinous egg mass.
Impact on world/humanity
They are eaten by various marine species due to their extremely small size. They are consumed by fish that are then eaten by penguins and polar bears. They are also consumed by sea birds, whales and commercially important fish, which they can render unsaleable if consumed in large quantities.
Since there is so little known about this tiny adorable creature I was not able to find a journal article. :( So i will just post more pictures!!!!