''Tritoniopsis elegans'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of dendronotid

nudibranch Nudibranchs () are a group of soft-bodied marine gastropod molluscs, belonging to the order Nudibranchia, that shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have b ...

. It is a marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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 nudibranch ...

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 naturalist, an entomologist, herpetologist, ornithologist, and malacologist. Biography Audouin was born in Paris and was educated in the field of medi ...

in 1826, the

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

being found in the

Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...

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 (genus), Cydia. Cerata, singular ceras, are anatomical structures found externally in nudibranch sea slugs, especially in aeolid nudibranchs, marine animal, marine opi ...

and

rhinophore A rhinophore is one of a pair of Chemoreceptor, chemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy in sea slugs, Marine (ocean), marine gastropod opisthobranch mollusks suc ...

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 is the old scientific order name for the informal group known as "soft corals". It is now an unaccepted name for class Octocorallia. It became deprecated . The following text should be considered a historical, outdated way of treatin ...

s on which it feeds, but it is

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

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 in which 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 ...

to feed on the invasive octocoral '' Carijoa riisei''. The only other known predators on this coral are the aeolid nudibranch ''

Phyllodesmium poindimiei ''Phyllodesmium poindimiei'' (AKA: Spun Of Light) is an Alcyonacea feeding, aeolid nudibranch Gastropod belonging to the family Facelinidae. Cerata are important in this clade in terms of their physical defense and efficient metabolic processes. ...

'' 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 in average len ...

''. ''Tritoniopsis elegans'' also feeds on the Chinese octocoral '' Cladiella krempfi'', and it has been found that the unusual

diterpene Diterpenes are a class of terpenes 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 a primary ...

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

Description

Distribution and habitat

Ecology

References

Further reading