At 6 mm in length, Pyrgocythara plicosa (C.B. Adams, 1850) is one of the local small-sized gastropods. The shell is elongate-fusiform, with the spire (coiled part minus last whorl) measuring about half shell length. The sculpture consists of 11−12 strong axial ribs crossed by about 5−6 spiral cords. The aperture has a strong indentation on the internal side of outer lip, and shell color is light-brown to reddish-brown, with bluish-white remnants of a periostracum.
The Plicate Mangelia, Pyrgocythara plicosa, from Sanibel. Photos by José H. Leal.