Atergatis roseus has a wide, smooth, oval carapace with convex almost entire, with no indication of regions and with bluntly crested anterolateral margins.

[2][3] Atergatis roseus has wide Indo-Pacific distribution being found from the Red Sea and eastern Africa, south to KwaZulu-Natal east along the coasts of the Indian Ocean into the Pacific as far as Fiji.

[1][3] In the eastern Mediterranean, A. roseus was first recorded from Israel in 1961,then from Lebanon and the southern coasts of Turkey and Syria.

[4] Atergatis roseus inhabits coral reefs and rocky substrata, from the low tide mark to a depth of 30 metres.

[6] It is omnivorous but a large part of its diet is made up of plant material, although specimens have been recorded feeding on fish.