Polymetme thaeocoryla is a species of fish in the family Phosichthyidae (lightfish).

[2][3] Its specific name is an anagram of the similar species, Polymetme corythaeola.

[4] It has no common name in English, but in Spanish is called luciérnaga musculosa ("muscular lightfish") and in French luisant grand feu ("gleaming [fish of] great fire").

[5][6] Polymetme thaeocoryla has a dark dorsum, with silver flanks and a black pigment on the outer caudal rays.

[4] Polymetme thaeocoryla is benthopelagic, living in the Atlantic Ocean at depths of 213–1,400 m (699–4,593 ft).