Brown Cone Shell, Conus brunneus

Brown Cone Shell, Conus brunneus. Shell collected off the beach in the greater Los Cabos area, Baja California Sur, January 2012. Size: 2.8 cm (1.1 inches) x 1.7 cm (0.8 inches).

Brown Cone Shell, Conus brunneus. Shell collected off the beach at Rancho San Cosme, Baja California Sur, November 2022. Size: 3.4 cm (1.4 inches) x 2.1 cm (0.8 inches). Photograph and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Phylogeny: The Brown Cone, Conus brunneus (W. Wood, 1828), is a gastropod mollusk that is a member of the Conidae Family of Cones. The genus Conus is one of eight genera in this family, and there are around eight hundred ten species in this genus. They are also known as Wood’s Brown Cone and in Mexico as Cono Bruno.

Description: Brown Cones have a low, but sometimes sharply peaked, spire. The whorl is knobby, extending to the shoulder as coronations. The exterior of the shell is a chestnut brown color with darker brown spiral lines and white blotches. The aperture is light gray and the anterior canal has a yellow tinge. The shell has a thick periostracum. Brown Cones reach a maximum of 6.5 cm (2.6 inches) in length and 3.9 cm (1.6 inches) in height.

Habitat and Distribution: Brown Cones are found on, and within, sand substrate, and under rocks. They live in the intertidal zone, and to depths up to 5 m (15 feet). They are a tropical Eastern Pacific species. In Mexican waters they range from Magdalena Bay, Baja California Sur to Guatemala, including the Revillagigedo Islands. They are found throughout the Gulf of California.

Ecology and Behavior: Sources vary significantly regarding the diet and reproduction of Brown Cones. All agree that they are predators, but some claim that they eat primarily mollusks, some claim fish, and others say polychaetes. The sources agree that they are gonochoric and reproduce sexually, but some describe it as external fertilization, and others as internal. 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 are consider to be of Least Concern.

Synonyms: Conus (Stephanoconus) brunneus, Conus interruptus and Stephanoconus brunneus.