Janolus
# Janolus

Janolus is a genus of small to large sea slugs, or more accurately nudibranchs, marine gastropod mollusks, in the family Janolidae. The name Janolus is derived from the two-headed god Janus, in ancient Roman mythology.

## Description

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.

## Distribution

Janolus species are found in many areas world-wide, including Europe, Australia, Japan and Africa.

## Ecology

### Habitat

This genus of nudibranch is found in shallow and subtidal waters.

### Feeding habits

Janolus species feed on Bryozoa, moss animals.

### Predators

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

Species in the genus Janolus include:

* Janolus anulatus Camacho-Garcia & Gosliner, 2006
* Janolus australis Bergh, 1884
* Janolus chilensis M.A. Fischer, Cervera & Ortea, 1997
* Janolus comis Er. Marcus, 1955
* Janolus eximius Miller & Willan, 1986
* Janolus faustoi Ortea & Llera, 1988
* Janolus flavoanulatus Pola & Gosliner, 2019
* Janolus hyalinus (Alder and Hancock, 1854)
* Janolus ignis Miller & Willan, 1986
* Janolus incrustans Pola & Gosliner, 2019
* Janolus kinoi Edmunds & Carmona, 2017
* Janolus mirabilis Baba & Abe, 1970
* Janolus mokohinau Miller & Willan, 1986
* Janolus mucloc (Er. Marcus, 1958)
* Janolus rebeccae Schrödl, 1996
* Janolus savinkini Martynov & Korshunova, 2012
* Janolus toyamensis Baba & Abe, 1970
* Janolus tricellariodes Pola & Gosliner, 2019

### Species brought into synonymy

* Janolus barbarensis (J. G. Cooper, 1863):synonym of Antiopella barbarensis (J. G. Cooper, 1863)
* Janolus capensis Bergh, 1907:synonym of Antiopella capensis (Bergh, 1907) (original combination)
* Janolus costacubensis Ortea & Espinosa, 2000:synonym of Janolus comis Er. Marcus, 1955
* Janolus cristatus (Delle Chiaje, 1841):synonym of Antiopella cristata (Delle Chiaje, 1841)
* Janolus flagellatus Eliot, 1906:synonym of Janolus hyalinus (Alder & Hancock, 1854) (dubious synonym)
* Janolus fuscus O'Donoghue, 1924:synonym of Antiopella fusca (O'Donoghue, 1924) (original combination)
* Janolus longidentatus Gosliner, 1981:synonym of Antiopella longidentata (Gosliner, 1981) (original combination)
* Janolus nakaza (Gosliner, 1981):synonym of Bonisa nakaza Gosliner, 1981
* Janolus novozealandicus (Eliot, 1907):synonym of Antiopella novozealandica Eliot, 1907
* Janolus praeclarus (Bouchet, 1975):synonym of Antiopella praeclara Bouchet, 1975
