Sphaeronassa mutabilis plioacuta gastropod mollusc collected from Pliocene sediments in Huelva, Spain. These marine gastropod shells are in very good condition; they exhibit coarse ribs and have relatively thick shells. These features were most likely adaptions which allowed them to exploit shallow, more turbulent waters. Growth lines can be seen towards the aperture lip and the shells are white in colour. These specimens measure between 3 and 4 cm in length i.e. from the base of the aperture to the apex of the shell. Supplied in small plastic bags with an information label.