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:MolluscaBase (2019). MolluscaBase. Janolus Bergh, 1884. Accessed on 2020-10-20. 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
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