Lumpy Morum Shell, Morum tuberculosum

Lumpy Morum Shell, Morum tuberculosum. Shell collected off the beach in the greater Los Cabos area, Baja California Sur, March 2009. Size: 2.6 cm (1.1 inches) x 1.8 cm (0.7 inches).

Phylogeny: The Lumpy Morum, Morum tuberculosum (Reeve, 1842), is a gastropod mollusk that is a  member of the Harpidae Family of Harp Shells. The genus Morum is one of three genera in this family, and there are forty-one species in this genus. They are also known as the Yellow-mouth Helmet and the Humped Morum Harp and in Mexico as Morum Jorobado or Casco Boca Amarilla.

Description: The Lumpy Morum shell is cylindrical in shape, with the exterior sculpted with concentric rows of tubercles. Their spire is low to flat and the aperture is long and narrow. The exterior of the shell is generally cream colored, with dark brown blotches and speckles. The interior is white to light yellow. Lumpy Morum Sshells reach a maximum of 4.3 cm (1.7 inches) in length and 3.0 cm (1.2 inches) in height.

Habitat and Distribution: Lumpy Morums are found in sand, or under rocks in sand, in the intertidal zone and to depths up to 15 m (50 feet). They are a subtropical to tropical Eastern Pacific species that are found in Mexican waters of the Pacific Ocean from Magdalena Bay, Baja California Sur south to Guatemala. They are found throughout the Sea of Cortez.

Ecology and Behavior: Lumpy Morums  are a poorly studied and understood species. There is very limited documentation of their diet, predation, reproduction or ecosystem interactions. Other species in Family Harpidae are predators that feed primarily on crabs and shrimps, which they capture by covering them with their large foot. They are gonochoric and reproduce sexually, with internal fertilization. The eggs are laid in protective capsules. 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 considered to be of Least Concern.

Synonyms: Morum xanthostoma and Oniscia tuberculosa.