| Janolus | |
|---|---|
| Janolus fuscus | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| (unranked): | clade Heterobranchia clade Euthyneura |
| Family: | Proctonotidae |
| Genus: | Janolus Bergh, 1884 |
| Species | |
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Janolus is a genus of small to large sea slugs, or more accurately nudibranchs, marine gastropod mollusks, in the family Proctonotidae.
The name Janolus is derived from the two-headed god Janus, in ancient Greek mythology.
Although these nudibranchs superficially resemble aeolid nudibranchs, this genus is in fact in the suborder Arminina.
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Adult individuals of Janolus species can be between 2.5 cm to 8 cm long, depending on the species. They are semi-translucent and the body is covered in short cerata.
The color of the cerata varies according to the species: in Janolus fuscus the cerata are orange and white tipped, whereas in Janolus barbarensis they are orange and blue tipped.
Janolus species are found in many areas world-wide, including Europe, Australia, Japan and Africa.
The species Janolus fuscus is found from the Kenai Peninsula, Alaska to central California and also in northern Japan.[1]
This genus of nudibranch is found in shallow and subtidal waters.
Janolus species feed on Bryozoa, moss animals.
In California, Navanax is a known predator of Janolus. Navanax tracks the slime of Janolus by using chemoreceptors. When Janolus is about to be caught, it rolls into a ball, leaving its cerata exposed.
Species in the genus Janolus include[2][3]: