Spiny Slipper Shell, Bostrycapulus latebrus 

Spiny Slipper Shell, Bostrycapulus latebrus. Shell collected off the beach in Los Cabos area, Baja California Sur, May 2020. Size: 2.0 cm (0.8 inches) x 1.4 cm (0.6 inches).

Spiny Slipper Shell, Bostrycapulus latebrus. Shell collected off the beach of Punta Chivato, Baja California Sur, May 2025. Size: 1.8 cm (0.7 inches) x 1.3 cm (0.5 inches) x 0.5 cm (0.2 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Spiny Slipper Shell, Bostrycapulus latebrus. Shell collected off the beach of Punta Chivato, Baja California Sur, May 2025. Size: 2.3 cm (0.9 inches) x 1.5 cm (0.6 inches) x 0.7 cm (0.3 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Spiny Slipper Shell, Bostrycapulus latebrus. Shell collected off the beach of Punta Chivato, Baja California Sur, May 2025. Size: 2.5 cm (1.0 inches) x 1.9 cm (0.7 inches) x 0.8 cm (0.3 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Phylogeny: The Spiny Slipper Shell, Bostrycapulus latebrus (Collin, 2005), is a gastropod mollusk that is a member of the Calyptraeidae Family of Cup-and-Saucer and Slipper Shells. The Bostrycapulus Genus is one of eleven genera in the Calyptraeidae Family, and there are ten species in the Bostrycapulus Genus. They are also known as the Obscure Slipper Shell and the Prickly Slipper Shell and in Mexico as Pique Espinoso.

Description: The Spiny Slipper Shell has a round outline, with one flat or concave side. The apex is spiraled and located near the margin. The exterior of the shell is sculpted with rows of scales or spines that spiral from the apex. The shelf covers about one half of the shells interior and may be notched at either end or in the center. The exterior color of the shell is a yellowish brown or gray brown, and some have darker brown bands. The interior may have brown spots or blotches and the shelf is white. Spiny Slipper Limpet Shells reach a maximum of 3.8 cm (1.5 inches) in length and 2.7 cm (1.0 inches) in height.

Habitat and Distribution: Spiny Slipper Limpets are found found attached to rocks and shells in the intertidal zone, and to depths up to 79 m (260 feet). They are a subtropical Eastern Pacific species that have a very limited range in Mexican waters being ENDEMIC to the southern half of the Sea of Cortez, ranging Punta Chivato, Baja California Sur to Cabo San Lucas, Baja California Sur.

Ecology and Behavior:  Spiny Slipper Limpets are suspension feeders that feed primarily on planktonic algae, which they filter from the water by use of their gills. They are protandrous hermaphrodites, beginning life as males and later becoming females. They reproduce sexually, with internal fertilization. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. From a conservation perspective they have not been formally evaluated. However, they are fairly common with a relatively wide distribution and should be considered to be of Least Concern.

Synonyms: None