Sepia tanybracheia is a species of cuttlefish native to the southeastern Indian Ocean. It is known only from the type locality. S. tanybracheia lives at depths of 200 to 205 m.

Males grow to a mantle length of 51 mm.

The type specimen was collected off Western Australia (12°36′S 123°45′E) and is deposited at the Museum of Victoria in Melbourne.

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