Longchaeus auricoma is a species of sea snail, a marine gastropod mollusc in the family Pyramidellidae, the pyrams and their allies.

It is yellowish-white, with fine golden yellow spiral lines between the sutures and on the base.

The whorls of the protoconch are small, deeply obliquely immersed in the first succeeding turn.

The ten whorls of the teleoconch are well rounded, feebly shouldered at the summit, scarcely at all contracted at the sutures.

[4] This marine species occurs in the Gulf of California and off Mazatlán, Mexico.