The Mucrospirifer thedforensis brachiopod ("butterfly shells") found in the Widder Formation of Arkona, Ontario, Canada. This creature lived in the Givetian Age (392-386 million years ago) of the Middle Devonian Period.
According to Wikipedia, this brachiopod is in the class Rhynchonellata (Articulata) and the order Spiriferida. The fossil shell definitely has beautiful wing shapes.
This page has an artistic interpretation of what a similar species might have looked like. One has to be impressed by the artist Emily S. Damstra's work.
Thanks to Dave for the fossils.