''Tritoniopsis elegans'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of dendronotid

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 ...

. It is a

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 ...

mollusc 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 esti ...

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 ...

Tritoniidae Tritoniidae is a taxonomic family of nudibranchs in the suborder Cladobranchia, shell-less marine gastropod molluscs.MolluscaBase (2018)Tritoniidae Lamarck, 1809.Accessed on 2021-01-01 This family includes some of the largest known nudibranchs, ...

and is found in the western Indo-Pacific. It was first described by the French naturalist

Jean Victoire Audouin Jean Victor Audouin (27 April 1797 – 9 November 1841), sometimes Victor Audouin, was a French natural history, naturalist, an entomologist, Herpetology, herpetologist, ornithologist, and malacologist. Biography Audouin was born in Paris and was ...

in 1826, the

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

being found in the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

Description

''Tritoniopsis elegans'' is a slender nudibranch growing to about , with several pairs of dendritic (branching)

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 ...

and

rhinophore A rhinophore is one of a pair of chemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy in sea slugs, marine gastropod opisthobranch mollusks such as the nudibranchs, sea har ...

s tipped with short tentacles. It varies in colour from translucent clear to translucent orange or orange-red and has a pattern of white opaque markings. The different colour forms do not seem to be a result of the animals' diet because the two forms sometimes occur alongside each other when the animals are feeding on the same colonial soft coral. The white form used to be known as ''Tritoniopsilla alba'' but this is now considered to be a synonym for ''T. elegans''.

Distribution and habitat

''Tritoniopsis elegans'' was described from the Red Sea. It has been reported from many localities in the western Indo-Pacific. It is known from the Red Sea, Tanzania, Japan, New Caledonia and eastern Australia. It is found on shallow water reefs, normally on the

soft coral Alcyonacea, or soft corals, are an order of corals. In addition to the fleshy soft corals, the order Alcyonacea now contains all species previously known as "gorgonian corals", that produce a more or less hard skeleton, though quite different f ...

s on which it feeds, but it is

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

and so is easily overlooked. In 2007, ''T. elegans'' was observed in Hawaii for the first time, having not been included in any previous surveys of marine invertebrates on the islands.

Ecology

''Tritoniopsis elegans'' is one of the only

predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

to feed on the invasive octocoral ''

Carijoa riisei ''Carijoa riisei'', the snowflake coral or branched pipe coral, is a species of soft coral in the family Clavulariidae. It was originally thought to have been native to the tropical western Atlantic Ocean and subsequently spread to other areas of ...

''. The only other known predators on this coral are the aeolid nudibranch '' Phyllodesmium poindimiei'' and the bearded fireworm ''

Hermodice carunculata ''Hermodice carunculata'', the bearded fireworm, is a type of marine bristleworm belonging to the Amphinomidae family, native to the tropical Atlantic Ocean and the Mediterranean Sea. Description Bearded fireworms are usually 15 centimetre ...

''. ''T. elegans'' also feeds on the Chinese octocoral '' Cladiella krempfi'', and it has been found that the unusual

diterpene Diterpenes are a class of chemical compounds composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being ...

s present in that coral accumulate in the nudibranch's mantle.

Description

Distribution and habitat

Ecology

References

Further reading