Bythaelurus is a genus of sharks belonging to the family Pentanchidae, the deepwater catsharks.

The genus Bythaelurus Compagno 1988 was first described as a subgenus of Halaelurus Gill 1862 based on several morphological characteristics including a soft body with thin skin, a bluntly rounded snout without a pointed, knob-like tip, and eyes not noticeably elevated on the dorsal surface of the head.

Members of this genus are generally found in deep water and have more somber body coloration.

[1] There are currently 14 recognized species in this genus:[2]

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