Leach, 1815
Dorsal surface of the body smooth and punctate, not tuberculate, sometimes pubescent. Carapace with postrostral and branchial carinae distinct; without posteromedian tooth. Distance between the orbits as long as or shorter than the distance separating each orbit from the nearest anterolateral angle. Orbits anteriorly open, placed on the anterior margin of the carapace. Cervical incision usually open, at least at the base. Fifth abdominal somite with postero-median spine. Mandibular palp consisting of a single segment.
Type Species: by monotypy: Ibacus peronii Leach, 1815.
At present 6 species of Ibacus are known. All are found at great depths in the Indo-West Pacific region, and most are of little or no economic importance. All are dealt with here.