Black-margined Nudibranch
Doriprismatica atromarginata
Tryon's Hypselodoris
Hypselodoris tryoni
About
A small, richly spotted sea slug that reaches about 10 cm, often found crawling in pairs across the reef with one animal trailing just behind the other.
- Length
- 10 cm
How to tell it apart
This species looks similar to several Goniobranchus sea slugs, but those have a wide purple line along the mantle edge and a lower, more rounded body. This species instead has only a thin blue or purple mantle-edge line, without the broader band.
Appearance
The body is brown with a white foot, and the back is covered in purple spots ringed in white or light brown. The gills are translucent white or light brown, and the two sensory horns on the head, called rhinophores, are brown to dark brown with fine circular white lines. A thin blue or purple line runs along the edge of the mantle. Colour varies somewhat between individuals, and this species raises and lowers its head as it crawls.
Habitat
It occurs widely across the tropical western Pacific, from Australia to the Philippines, where it feeds on sponges.
Did you know?
It is often found crawling in pairs, with one animal attached directly to the back of the other.
Log it in Into the Blue
Describe what you saw and we name it, then keep every species you find in your Oceandex.
