The Delicate Ark, Fugleria tenera (C.B. Adams, 1845), is an uncommon western Atlantic member of the Arcidae, a family of marine bivalves that also includes the Turkey Wing and the Transverse Ark, among others. The delicate Ark may reach slightly more than one inch (25 mm) in size. It differs from others, related species by its thin shell, with an alternating pattern of thicker and thinner radial ribs, which are in turn crossed by concentric ridges. Living delicate Arks have a hairy, rich periostracum that is more abundant toward the posterior (more pointed) shell end.
The species is known locally from a single valve, found recently (last December) by Suzanne J. Hewitt on the Captiva side of Blind Pass. Photos by José H. Leal.