A new species of pinnotherid crab, Orthotheres haliotidis, is described from two species of Australian abalone, Haliotis asinina Linnaeus, 1758, and H. squamata Reeve, 1846. Its morphology is recorded using light and scanning electron microscopy. The report is the second record of the predominantly American genus Orthotheres in the western Pacific, the first confirmed record of a pinnotherid crab from any species of abalone, and the first record of a pinnotherid associated with H. squamata.

Haliotis asinina Linnaeus, 1758. Left adult. Right juvenile

Haliotis squamata Reeve, 1846