Teasel Murex Shell, Favartia dipsacus

Teasel Murex Shell, Favartia dipsacus. Size: 7.6 cm (3.0 inches) x 3.8 cm (1.5 inches) x 3.8 cm (1.5 inches). Shell collected off the beach in the greater Agua Verde area, Baja California Sur, February 2020. Collection and photography courtesy of Barry Mastro, Escondido, California. Identification courtesy of Bob Hillis, Ivins, Utah and should be considered a tentative identification as this shell is relatively unknown and the size of the pictured shell exceeds the known maximum for the Teasel Murex.

Phylogeny: The Teasel Murex Shell, Favartia dipsacus (Broderip, 1833), is a gastropod mollusk that is a member of the Muricidae Family of Rock Shells. The genus Favartia is one of one hundred ninety-eight genera in this family, and there are one hundred twelve species in this genus. They are named for their resemblance to the head of a Teasel or Thistle Plant. Until recently this species fell under the genus Murexsul.

Description: Teasel Murex Shells are solid, fairly globose shells which have six whorls. They have seven to nine varices and a moderately high spire. Their aperture is circular to slightly oval and the canal is moderately long and open. The axial ribs and spines vary in length between specimens. The exterior of the shells is whitish with varying numbers of brown bands or blotches. The interior is white. Teasel Murex Shells reach a maximum of 7.6 cm (3.0 inch) in length and 3.8 cm (1.5 inches) in height.

Habitat and Distribution: Teasel Murexs are found on cobbles and rocks at depths between 20 m (66 feet) and 37 m (121 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.

Ecology and Behavior: Teasel Murexls are predators that feed primarily on barnacles and bivalves. They are gonochoric and reproduce sexually, with internal fertilization. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formulally doucmented. From a conservation perspective they have not been formally evaluated.

Synonyms:  Murex dipsacus, Murex octonus, and Murexsu dipsacus.