Platvoet, De Bruyne and Gmelig Meyling, 1995
Largest male specimen examined 24 mm, largest female 11 mm.
Male: Head without a dorsal spine. Antenna 1 long, about 3/4 of the body length, peduncle 3 times as long as the 22-segmented flagellum. Peduncle covered with short setules. Antenna 2 less than half the length of antenna 1, ventrally with two rows of setae. Mandibles with molar, without palp. Left and right lacinia with equal dentation. Maxillule with a two-segmented palp. Fourth segment of the maxillipedal palp covered with rows of very fine setules.
First and second pereion segments densely covered with setae, third to seventh segments with spines only. First pereiopod short, with setation on the posterior margin only. Second pereiopod long, densely covered with setae. Pereiopod 5 < than 6, and 6 < 7.
Female without setation on the first and second pereionite, dorsal and lateral spines on pereionites 3 to 7.
Living specimens of both male and female Caprella macho are brightly orange to red in colour, the brood pouch of the female being pale white with dark red dots.
Living animals are very active, both free-swimming as hiding between the accompanying flora and fauna.
Only known from Dutch coastal waters.
In the Atlantic there are no Caprellid species comparable with C. macho . The species might be introduced from East Asia, where Caprella mutica is quite similar.