Mexichromis antonii is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Chromodorididae.[1] [2]
The holotype of this species was collected in of water at Punta Aguja (near Mulege), Baja California, Mexico (26.8833°N -167°W). Three paratypes were also included in the original description, from Isla San Jose, (24.8833°N -144°W), Los Islotes, (24.6°N -134°W) and Santiago Bay, near Manzanillo, Colima, (19.1°N -127°W). It has been reported from the Gulf of California south to Panama.[3]
Mexichromis antonii has a light blue mantle with two bands of colour at the edge, inner black and outer yellow-orange. There is a mid-dorsal line of white which is broken into elongate spots surrounded by a pink-magenta region which stretches from the rhinophore bases to the gill. The light blue area is divided longitudinally by a faint black line. The bases of the rhinophores and gill leaves are pale magenta with the outer half black.[4] Grows to in length.[3]