Real Bastard Trumpeter

Mendosoma lineatum has an elongate and compressed body, the depth of the body fits into its standard length 2.7-4.3 times. Larger specimens, with a standard length in excess of 10 cm (3.9 in). may have a hump behind the head. They have a pointed snout with a small, highly protrusible mouth with one row of small conical teeth in the upper jaw and no teeth in the lower jaw or on the roof of the mouth. The dorsal fin has 22-25 spines and 23-27 soft rays while the anal fin contains 3 spines and 17-21 soft rays. This species grows to a maximum total length of 40 cm (16 in). The overall colour is dark bluish-green fading to silvery on the belly. There are rows of brown spots creating thin stripes along the flanks, becoming more reticulated in pattern on the back.

Mendosoma lineatum is found in the subantarctic and temperate waters of the Southern Ocean around New Zealand, Chile and Tasmania, as well as Gough Island in the South Atlantic, and Île Saint-Paul and Amsterdam Island in the southern Indian Ocean. This species is found on rocky reefs, frequently where there are surge channels, in tidal pools and off steep drop offs.