Sanguine Trivia Shell, Pseudopusula sanguinea

Sanguine Trivia Shell, Pseudopusula sanguinea. Shell collected off the beach of Bahía Concepción, Baja California Sur, October 2019. Size: 1.0 cm (0.4 inches) x 0.7 cm (0.3 inches). Colllection and photograph courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The Sanguine Trivia Shell, Pseudopusula sanguinea (Gray, 1832), is a gastropod mollusk that is a member of the Triviidae Family of Trivia Shells. The genus Pseudopusula is one of sixteen genera in this family, and there are fifteen species in this genus. They are also known as the Bloody Trivia Shell and in Mexico as Trivia Mancha Roja.

Description: Sanguine Trivia Shells are small in stature and somewhat egg-shaped. They have eleven strong spiral ribs that cross the dorsal surface of the shell. These shells have an internal spire and a curved slit-like aperture that has toothed lips. They may be brown, mahogany, or purplish brown in color, with pale ribs. They have a reddish stain on their dorsal surface. The Sanguine Trivia Shells reach a maximum of 1.5 cm (0.7 inches) in length and 1.0 cm (0.4 inches) in height.

Habitat and Distribution: Sanguine Trivias are found under rocks in the intertidal zone, and to depths up to 60 m (200 feet). They are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean with the exception that they are absent from north of Magdalena Bay, Baja California Sur, along the central and northwest coasts of the Baja Peninsula and north of Bahía San Carlos, Sonora, in the Sea of Cortez.

Ecology and Behavior: Sanguine Trivias are predators that feed primarily on sea squirts (Ascidians). They are gonochoric and reproduce sexually, with internal fertilization. The eggs are laid in protective capsules. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. From a conservation perspective the Sanguine Trivia 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: Cypraea sanguinea, Niveria carabus, Niveria sanguinea, Pusula (Pusula) carabus, and Trivia (Pusula) sanguinea.