''Janolus'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of small to large
sea slug
Sea slug is a common name for some marine invertebrates with varying levels of resemblance to terrestrial slugs. Most creatures known as sea slugs are gastropods, i.e. they are sea snails (marine gastropod mollusks) that over evolutionary t ...
s, or more accurately
nudibranch
Nudibranchs () are a group of soft-bodied marine gastropod molluscs which shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to matc ...
s,
marine
Marine is an adjective meaning of or pertaining to the sea or ocean.
Marine or marines may refer to:
Ocean
* Maritime (disambiguation)
* Marine art
* Marine biology
* Marine debris
* Marine habitats
* Marine life
* Marine pollution
Military
* ...
gastropod
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...
s, in the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Janolidae
Janolidae is a family of sea slugs, nudibranchs, marine gastropod molluscs, in the clade Euthyneura.
Genera
Genera in the family Janolidae include:MolluscaBase (2019). MolluscaBaseJanolidae Pruvot-Fol, 1933.Accessed on 2020-10-20.
* '' Antiopel ...
.
The name ''Janolus'' is derived from the two-headed god
Janus
In ancient Roman religion and myth, Janus ( ; la, Ianvs ) is the god of beginnings, gates, transitions, time, duality, doorways, passages, frames, and endings. He is usually depicted as having two faces. The month of January is named for Janu ...
, 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
:''The tortrix moth genus ''Cerata'' is considered a junior synonym of ''Cydia.
Cerata, singular ceras, are anatomical structures found externally in nudibranch sea slugs, especially in aeolid nudibranchs, marine opisthobranch gastropod mollusks ...
.
Distribution
''Janolus'' species are found in many areas world-wide, including
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
,
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
,
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
and
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
.
Ecology
Habitat
This genus of nudibranch is found in shallow and
subtidal
The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth.
From the point of view of marine biology it forms a relatively stable and well-illuminated ...
waters.
Feeding habits
''Janolus'' species feed on
Bryozoa
Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a l ...
, moss animals.
Predators
In California, ''
Navanax
''Navanax'' is a genus of sea slugs, marine opisthobranch gastropod mollusks in the family Aglajidae.Bouchet, P. (2012). Navanax. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=224591 ...
'' is a known predator of ''Janolus''. ''Navanax'' tracks the slime of ''Janolus'' by using
chemoreceptors
A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecept ...
. 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
''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 ...
''
Camacho-Garcia & Gosliner, 2006
* ''
Janolus australis
''Janolus'' is a genus of small to large sea slugs, or more accurately nudibranchs, marine (ocean), marine gastropod mollusks, in the family (biology), family Janolidae. The name ''Janolus'' is derived from the two-headed god Janus (mythology), J ...
''
Bergh, 1884
* ''
Janolus chilensis
''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 ...
''
M.A. Fischer, Cervera & Ortea, 1997
* ''
Janolus comis
''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 ...
''
Er. Marcus, 1955
* ''
Janolus eximius
''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 ...
''
Miller & Willan, 1986
* ''
Janolus faustoi
''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 ...
''
Ortea & Llera, 1988
* ''
Janolus flavoanulatus
''Janolus flavoanulatus'' is a sea slug species. The specific name is derived from Latin words flavus (“yellow”) and anulatus (“ringed”). These soft-bodied mollusks are known for their extraordinary colors and prominent forms. The first d ...
''
Pola & Gosliner, 2019
* ''
Janolus hyalinus
''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 ...
''
(Alder and Hancock, 1854)
* ''
Janolus ignis
''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 ...
''
Miller & Willan, 1986
* ''
Janolus incrustans
''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 ...
''
Pola & Gosliner, 2019
* ''
Janolus kinoi
''Janolus'' is a genus of small to large sea slugs, or more accurately nudibranchs, marine (ocean), marine gastropod mollusks, in the family (biology), family Janolidae. The name ''Janolus'' is derived from the two-headed god Janus (mythology), J ...
''
Edmunds & Carmona, 2017
* ''
Janolus mirabilis
''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 ...
''
Baba & Abe, 1970
* ''
Janolus mokohinau
''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 ...
''
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
''Antiopella barbarensis'', common name Santa Barbara janolus, is a colourful sea slug, a cladobranch nudibranch, a marine gastropod mollusc in the family Janolidae.MolluscaBase (2019). MolluscaBase''Antiopella barbarensis'' (J. G. Cooper, 1863). ...
''
(J. G. Cooper, 1863)
* ''Janolus capensis''
Bergh, 1907:synonym of ''
Antiopella capensis
''Antiopella capensis'', originally described as ''Janolus capensis'', the Cape silvertip nudibranch, is a beautiful species of nudibranch, or sea slug. It is a marine gastropod mollusc in the family Proctonotidae.
Apart from striking difference ...
''
(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
''Antiopella cristata'', sometimes known by the common name crested aeolis, is a species of nudibranch, a marine gastropod mollusc in the family Janolidae.
Taxonomy
Previously some authors synonymised ''Antiopella'' with ''Janolus'' and assigne ...
''
(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
''Antiopella'' is a genus of small to large sea slugs, or more accurately nudibranchs, marine gastropod mollusks, in the family Janolidae.
Description
Species of ''Antiopella'' were included in '' Janolus'' for a period of time.Pola M., Hallas ...
''
(O'Donoghue, 1924) (original combination)
* ''Janolus longidentatus''
Gosliner, 1981:synonym of ''
Antiopella longidentata
'' Antiopella longidentata'' (Gosliner, 1981), previously named ''Janolus longidentatus'', the medallion silvertip nudibranch, is a species of nudibranch, or sea slug. It is a marine gastropod mollusc in the family Proctonotidae.
Apart from stri ...
''
(Gosliner, 1981) (original combination)
* ''Janolus nakaza''
(Gosliner, 1981):synonym of ''
Bonisa nakaza''
Gosliner, 1981
* ''Janolus novozealandicus''
(Eliot, 1907):synonym of ''
Antiopella novozealandica
''Antiopella'' is a genus of small to large sea slugs, or more accurately nudibranchs, marine gastropod mollusks, in the family Janolidae.
Description
Species of ''Antiopella'' were included in '' Janolus'' for a period of time.Pola M., Hallas ...
''
Eliot, 1907
* ''Janolus praeclarus''
(Bouchet, 1975):synonym of ''
Antiopella praeclara
''Antiopella'' is a genus of small to large sea slugs, or more accurately nudibranchs, marine (ocean), marine gastropod mollusks, in the family (biology), family Janolidae.
Description
Species of ''Antiopella'' were included in ''Janolus'' for a ...
''
Bouchet, 1975
References
{{Taxonbar, from=Q3020001
Proctonotidae