Fred Baker’s Spindle Shell, Hesperaptyxis fredbakeri

Fred Baker’s Spindle Shell, Hesperaptyxis fredbakeri. Size: 4.2 cm (1.7 inches) x 1.7 cm (0.7 inches). Shell collected from within the estuary of the Magdalena Bay complex, Baja California Sur, October 2018. Collection, photograph and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: Fred Baker’s Spindle Shell, Hesperaptyxis fredbakeri (H.N. Lowe, 1935), is a gastropod mollusk that is a member of the Fasciolariidae Family of Spindles, Horse Conchs and Tulip Shells. The genus Hesperaptyxis is one of sixty-eight genera in this family, and there are six species in this genus. The shell is named after Fred Baker, a physician, educator, and amateur malacologist in San Diego. He contributed significantly to the collections of the San Diego Natural History Museum and the Scripps Institution of Oceanography.

Description: Fred Baker’s Spindle Shell is light in structure and consists of seven whorls, with numerous spiral ridges running along the whorls. There are also twelve strong ribs, which run the shell’s length. It has a high spire, an open siphon canal, and a medium- sized, oval, aperture. The aperture has a thin outside lip that is unsculpted. The exterior of the shell is cream to brown in color, and may have white spiral and/or lengthwise lines. The interior is white to bluish, with some exterior color showing through. Fred Baker’s Spindle Shells reach a maximum of 4.9 cm (1.9 inches) in length and 2.0 cm (0.8 inches) in height.

Habitat and Distribution: Fred Baker’s Spindle Shells are found attached to rocks at depths between 12 m (40 feet) and 100 m (340 feet). They are a subtropical Eastern Pacific species. They have a very limited range in Mexican waters. They are endemic to the Gulf of California, ranging from San Felipe, Baja California,  to Santa Rosalia, Baja California Sur.

Ecology and Behavior: Fred Baker’s Spindle Shells are a poorly studied and understood species. There is very limited documentation of their diet, predation, reproduction or ecosystem interactions. Other species in Family Fasciolaridae are predators that consume barnacles, bivalves, gastropods, or worms. In turn they are preyed upon by sea stars, shore birds, crabs, fish, crabs, predatory mollusks and sea stars. 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 consider to be of Least Concern.

Synonyms: Fusinus consagensis and Fusinus fredbakeri.