Armored ‘Flight’…? Like its fellow pteropod the sea angel, the sea bu

Armored ‘Flight’…?

Like its fellow pteropod the sea angel, the sea butterfly(Limacinahelicina) is a 'wing-footed’ pelagic gastropod that spends its time fluttering about in the water column. 

But unlike the sea angel, the sea butterfly is equipped with a tiny shell. This shell is among the thinnest recorded for shelled gastropods: shells measuring 0.5–6 mm in diameter are only 2–9 μm thick! Yes, their shells are just a thousandth of a millimeter thick.

The thinness of the sea butterfly’s shell makes its function in defense doubtful. However, this lightweight shell has allowed L. helicina to take to the 'skies’ (or rather, the water column)—a way of life denied to its more heavily-armored, bottom-dwelling cousins, the sea snails. 

Image source: Alexander Semenov

Reference:Sato-Okoshi et al.2010.