Platycythara elata, common name the elongate mangelia, is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.

(Original description) The small, elongated, narrow shell is translucent white with streaks and lines of dark brown or yellow.

These cross about (on the body whorl) fifteen transverse rounded riblets, which extend from near the suture forward to the siphonal canal.

The outer lip is angulated at the shoulder, with a broad shallow rounded anal notch, thin edge, and smooth interior.

[2] This species occurs in the Atlantic Ocean off North Carolina to West Florida, USA; in the Antilles off Martinique and Guadeloupe.