The lined headshield slug with orange in the pattern rather than blue alone.
A headshield slug to about 3 cm, the body dark brown to black and marked with fine longitudinal lines of orange, cream and pale blue, with a squared shield across the head and the rear of the foot drawn out into two unequal tails. Chelidonura varians has the same build but carries electric blue lines on black with no orange in the pattern, and C. electra is white with a dark border. Animals vary in how much orange they show, but its presence is the working separation.
Like the rest of the genus it has no radula and hunts acoel flatworms, following their mucus trails over sand and algal film and taking them whole with a muscular pharynx. It is reported from the Indo-Pacific, the Caribbean and the tropical Atlantic, which is an unusually wide range for a shallow-water sea slug and probably conceals more than one species; the Coral Triangle animals are the ones the name is normally applied to.
Recorded from the shallows to about 20 m on sand and rubble, active in daylight.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
