Donkey Thorn Oyster Shell, Spondylus limbatus
Donkey Thorn Oyster Shell, Spondylus limbatus. Shell provided by the commercial fishermen of the greater Los Cabos area, March 2014. Size: 5.8 cm (2.3 inches) x 5.3 cm (2.1 inches).
Phylogeny: The Donkey Thorn Oyster, Spondylus limbatus (G.B. Sowerby, II, 1847), is a bivalve mollusk that is a member of the Spondylidae Family of Spiny Oysters. Spondylus is the only genus in this family, and the are seventy-five species in this genus. This species is also known as the Cat’s Tongue Oyster. They are known in Mexico as Almeja Burra, Callo Escarlopa and Ostra Espinosa Burricais.
Description: The Donkey Thorn Oyster shell is solidly built and oval shaped. The external surface has radiating lines with short spines; in older individuals the spines may be worn down. The exterior of the shell is pinkish-red and the interior is white, with a purplish red border. The Donkey Thorn Oyster shell reaches a maximum of 25 cm (9.7 inches) in length and 21 cm (8.3 inches) in width.
Habitat and Distribution: Donkey Thorn Oysters are found attached to solid substrates from the intertidal zone to depths up to 53 m (175 feet). They are subtropical to tropical Eastern Pacific species. In Mexican waters they range from San Alijo Rocks, Baja California Sur to Guatemala. In the Gulf of California they are found from San Felipe, Baja California to Cabo San Lucas, Baja California Sur.
Ecology and Behavior: Donkey Thorn Oysters are suspension feeders that feed primarily on planktonic algae and suspended organic matter. They are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization. There is no mention in the available literature of them engaging in any types of parasitic, commensal, or symbiotic relationships. From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.
Synonyms: Spondylus calcifer, Spondylus coccineus, Spondylus lamarckii, Spondylus punicus, Spondylus radula, and Spondylus smithii.