Spondylus limbatus G. B. Sowerby II 1847

Spondylus limbatus G. B. Sowerby II, 1847 Description According to Keen (1971), Poutiers (1995), Coan and Valentich-Scott (2012) and Lodeiros et al. (2016), Spondylus limbatus shows considerable variability in shell shape, ranging from irregularly rounded to distorted. It has an exterior surface with strong radial ribs bearing short, spathate or pointed spines (when preserved), which may decrease in size and eventually disappear; the right valve likewise exhibits concentric foliations around the attachment area, which can be rather extensive. Hinge teeth are robust and thick, brown in the left valve and white in the right valve. The adductor muscle scar varies from shallow to deep, with a ventral callus. Colourations, most evident along the broad inner margin, range from purple to orange hues. Marginal crenulations are fine and numerous. The shell can reach up to 25 cm in length. Diagnosis The hinge teeth are generally more robust, large and brown and the adductor muscle scar is deeply impressed; the spines also differ in shape and arrangement and, when the specimen retains the right valve, it may exhibit a broad attachment area (Lodeiros et al. 2016), which distinguishes it from related species. Additionally, the sculpture pattern of the ventral margin consists of fine and numerous crenulations. Dark and intense purple hues are characteristic of Spondylus limbatus, whereas orange and reddish tones may cause confusion with S. crassisquama; therefore, several morphological characters should be considered for reliable macroscopic identification. Notes Spondylus calcifer P. P. Carpenter, 1857 is one of the unaccepted synonyms of this species (MolluscaBase 2025).