Atergatis subdentatus, also known as the red reef crab,[1] dark-finger coral crab[1] or eyed coral crab,[2] is a species of crab in the family Xanthidae.
Atergatis subdentatus has a compact shape, and may appear either uniform crimson in colour, or may have an irregularly mottled yellow on a crimson background.[3] It has a broadly subquadrilateral carapace which grows to about wide,[2] and has finely punctulated by the anterior and antero-lateral borders.[4] It normally has an orange spot in the centre of the carapace, often with two small, white 'eyes' within.[2]
The arms have a flattish inner surface with two, inward-pointing teeth. Beside the teeth are brush-like hairs grouped together in four or five bundles.[4]
The type locality for this species is Japan, and it can be found around many of the Japanese islands. It also occurs in the waters of Taiwan,[4] Singapore, and rarely in the Lakshadweep Islands and Gulf of Mannar.[3]
This species lives on coral reefs and rocky beaches at a range of 3- in depth.[3]