Carpenter’s Turrid Shell, Megasurcula carpenteriana
Carpenter’s Turrid Shell, Megasurcula carpenteriana. Shell collected offshore San Diego, California, May 1998. Size: 7.5 cm (2.9 inches) x 3.0 cm (1.2 inch). Collection, identification and photo courtesy of Bob Hillis, Ivins, Utah.
Phylogeny: Carpenter’s Turrid, Megasurcula carpenteriana (Gabb, 1865), is a gastropod mollusk that is a member of the Pseudomelatomidae Family of Turrid Shells. The Megasurcula Genus is one of fifty-four genera in this family, and there are only two species in this genus. The genus name Megasurcula comes from Greek and Latin roots and means “large siphon.” This shell was named in honor of Philip Pearsall Carpenter who was a 19th century English minister and malacologist. He moved to Canada, and contributed significantly to North America malacology. They are known in Mexico as Túrido de Carpenter.
Description: Carpenter’s Turrid Shells are elongate and fusiform (spindle-shaped). The body whorl is large and the spire is moderately high. They consist of six to eight whorls. The shoulders may be rounded or well-defined and sculpted with knobs. These shells are sculpted with axial striae. The subsutural area (top of body whorl) is slightly concave. The aperture is long with a siphonal notch at the anterior end. The posterior notch is well defined. The outer lip is thin and smooth. The columella is smooth and curved. Carpenter’s Turrid Shells are yellowish to pinkish in color with narrow, dark brown, spiral, bands. They have a corneous operculum and a thin periostracum. The living animal is yellow with white spots. They are medium-sized shells, with the largest specimens reaching around 9.5 cm (3.7 inches) in length. Carpenter’s Turrid Shells are similar in appearance to Cooper’s Nutmeg Shell, Cancellaria cooperii (larger, heavier, with axial ribs, and obvious knobs) and Stearns’ Turrid Shell, Megasurcula stearnsiana (smaller, more streamlined, wider brown bands).
Habitat and Distribution: Carpenter’s Turrids are found on sandy substrates, at depths between 15 m (49 feet ) and 92 m (302 feet). These shells are a subtropical Eastern Pacific species that have a limited range in Mexican waters of the Pacific Ocean being found from Isla Cedros, Baja California, northward along the central and northwest coasts of the Baja Peninsula.
Ecology and Behavior: Turrid Shells are similar to Cone Shells being venomous predators that utilize their uniquely designed radula as a harpoon to capture and then envenomate their prey. The venom paralyzes the prey animal. The diet of Carpenter’s Turrid Shells is poorly understood, beyond “various small invertebrates”. They are gonochoric and reproduce sexually. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. From a conservation perspective Carpenter’s Turrids have not been formally evaluated, however, they should be considered to be of Least Concern being fairly common with a relatively wide distribution.
Synonyms: Bathytoma carpenteriana, Bathytoma tremperiana, Conus carpenterianus, Conus tremperianus, Cryptoconus tremperianus, Megasurcula granti, Megasurcula tremperiana, and Pleurotoma (Surcula) carpenteriana.