The Orange Barred Mexichromis (Mexichromis macropus) nudibranch is found in the temperate waters around the southern part of Australia. It has been recorded in SW Western Australia, South Australia, Tasmania, Victoria, New South Wales and southern Queensland.

Mexichromis macropus is different in appearance from other Australian species of Mexichromis as it has a mantle border that consists of radially arranged orange or yellow stripes rather than spots or longitudinal lines. The body colour varies from white to purple and generally always has scattered pointed papillae that are tipped in purple. Dr Bill Rudman from the Australian Museum named this species macropus after the genus name for the kangaroo, as the first specimens he had came from Kangaroo Island in South Australia. Mexichromis macropus grows to a maximum length of approximately 3cm.