Sad Miter Shell, Strigatella tristis

Sad Miter Shell, Strigatella tristis.  Shell courtesy of the commercial fishermen of the greater Los Cabos Area, January 2010. Size: 2.5 cm (1.0 inch) x 1.1 cm (0.4 inches).

Phylogeny: The Sad Miter Shell, Strigatella tristis (Broderip, 1836), is a gastropod mollusk that is a member of the Mitridae Family of Miters. The genus Strigatella is one of thirty-six genera in this family, and there are thirty-seven species in this genus. They are known in Mexico as Mitra Triste.

Description: The Sad Miter Shell is fusiform (spindle-shaped) with five or six slightly convex whorls. The body whorl is large and the spire is moderate in height. The shell is sculpted with low rounded axial ridges. The aperture is narrow and covers about one-half the shell length. The inner lip has 3 folds and the outer lip is thick and smooth. The exterior may be grayish-brown, olive brown, or dark brown in color. Most individuals have a white or light brown band along the top of each whorl. The interior is white to gray, sometimes with a brown wash. The Sad Miter Shells reach a maximum of 3.7 cm (1.5 inches) in length and 1.6 cm (0.6 inches) in height.

Habitat and Distribution: Sad Miter Shells are found on sand and mud substrates. They live in the intertidal zone and to depths of 25 m (80 feet). They are a subtropical to tropical Eastern Pacific species. In Mexican waters they range from Magdalena Bay, Baja California Sur to Guatemala including the Revillgigedo  and Tres Marias islands. They are found throughout the Gulf of California.

Ecology and Behavior:  Sad Miter Shells are a poorly studied and understood species. There is very limited documentation of their diet, predation, reproduction or ecosystem interactions. Other species in this genus feed on sipunculid worms, tube worms, and mollusks.  They are gonochoric and reproduce sexually,  with internal fertilization. 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: Mitra (Strigatella) tristis, Mitra albofasciata, Mitra dolorosa, Mitra salinasensi, and Mitra tristis.