Domiporta filaris


Domiporta filaris, commonly known as the file mitre, is a species of sea snail, a marine gastropod mollusc in the family Mitridae, the miters or miter snails. The species was originally described by Carl Linnaeus in 1771 as Voluta filaris, based on shell morphology alone, as was typical for the period.

Description

The shell is fusiform, typically slender to moderately stout, with a length ranging from approximately 14 mm to 55 mm.
The shell surface is finely sculptured with extremely fine, decussate striae, giving a subtly reticulate appearance. The whorls are encircled by raised, thread-like spiral cords, which are characteristically reddish or rufous in colour, contrasting with the otherwise pale to white shell.
The number and prominence of these spiral cords varies: early descriptions note three cords on the upper whorls, increasing to up to twelve on the body whorl. Later authors documented considerable intraspecific variation, with some forms bearing fewer, thicker cords and others more numerous, finer ones.
The aperture is elongate, with a simple to weakly crenulated outer lip, white internally. The columella bears multiple oblique plaits, usually three to four, a feature that contributed to later taxonomic debate regarding species limits within the group. The base of the shell is slightly effuse and externally margined.

Taxonomy and variation

Born redescribed the species as Voluta filosa, emphasising the finely reticulate shell sculpture, the raised spiral cords, and a quadriplicate columella, and introduced the vernacular name Die Schnurwalze.
In the mid-19th century, Philippi transferred the species to the genus Mitra and recognised three morphological forms within what he considered a single species, Mitra filosa. These forms differed mainly in shell slenderness and in the number, thickness, and position of the spiral cords, but were regarded as varieties rather than distinct species. One of these forms was reported from the Marquesas Islands, indicating possible geographic variation.
Modern classifications place the species in the genus Domiporta, recognising the historical names Voluta filaris Linnaeus, 1771 and Voluta filosa Born, 1780 as synonyms of the same taxon, although not officially accepted.

Distribution

This species occurs in the Red Sea, in the Indian Ocean off Chagos and the Mascarene Basin and in the Pacific Ocean off Hawaii and Australia.