Pterotrachea coronata, also known as a sea elephant, is a species of large floating sea snail, a pelagic gastropod mollusc in the family Pterotracheidae.

This pelagic snail is not at all closely related to the pelagic opistobranchs such as the sea angels and sea butterflies. It is in the family Pterotracheidae, which is in the clade Littorinimorpha, and as such it is related to such families as the tritons (Ranellidae) and the tun shells (Tonnidae).

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