''Pseudunela viatoris'' 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 ...

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 ...

, an

acochlidian Acochlidiacea, common name acochlidians, are a taxonomic clade of very unusual sea snails and sea and freshwater slugs, aquatic gastropod mollusks within the large clade Heterobranchia. Acochlidia is a variant spelling. Description These ar ...

, a shell-less

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 ...

in the family

Pseudunelidae ''Pseudunela'' is a genus of minute sea slugs, acochlidians, shell-less marine or temporary brackish or brackish gastropod mollusks in the clade Acochlidiacea. ''Pseudunela'' is the only genus in the family Pseudunelidae. ''Pseudunela'' is the t ...

. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''viatoris'' is after the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word “viator” (engl. pilgrim/voyager) according to its supposed ability to travel over long distances.

Distribution

''Pseudunela viatoris'' is known from

Viti Levu Viti Levu (pronounced ) is the largest island in the Republic of Fiji. It is the site of the nation's capital, Suva, and home to a large majority of Fiji's population. Geology Fiji lies in a tectonically complex area between the Australian P ...

, Fiji and Gili Lawa Laut, Indonesia. The type locality is Fiji, Viti Levu,

Laucala Bay Laucala (pronounced ) is one of a triplet of small islands that lie to the east of Thurston Point on the island of Taveuni in Fiji. The privately owned islands are the site of the Laucala Resort. The total land area of the main island is . It is ...

, Nukumbutho Island, GPS: 18°10.47′S, 178°28.34′E.

Description

The body size of living specimens of ''Pseudunela viatoris'' is 3–4 mm. The body is divided into an anterior head-foot complex and a posterior elongated visceral hump. The paired labial

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s are broad at the base and taper to the end. The

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 are tapered and shorter and thinner than the labial tentacles. The densely

ciliated The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projecti ...

foot is as broad as the anterior head-foot complex and extends about one third of the elongated visceral hump. The heart bulb is visible externally in the anterior part of the visceral hump on the right body side. Subepidermal, needle-shaped calcareous

spicule Spicules are any of various small needle-like anatomical structures occurring in organisms Spicule may also refer to: *Spicule (sponge), small skeletal elements of sea sponges *Spicule (nematode), reproductive structures found in male nematodes ( ...

s are sparsely distributed in the cephalic tentacles, the foot and the visceral hump; in the anterior part of the latter they are larger than in the posterior part. The body colour is whitish translucent, the

digestive gland The hepatopancreas, digestive gland or midgut gland is an organ of the digestive tract of arthropods and molluscs. It provides the functions which in mammals are provided separately by the liver and pancreas, including the production of digestive e ...

is brownish coloured (in specimens from Indonesia: orange-brownish shining through the epidermis). Epidermal glands are distributed particularly over the visceral hump. Whereas eyes are not visible externally in specimens from Fiji, eyes are weakly visible in some specimens from Indonesia. Eye diameter is 30-35 µm. Pseudunela viatoris 3

Nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...

digestive system The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller compone ...

circulatory system The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...

excretory system The excretory system is a passive biological system that removes excess, unnecessary materials from the body fluids of an organism, so as to help maintain internal chemical homeostasis and prevent damage to the body. The dual function of excreto ...

and

reproductive system The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are als ...

are described by Neusser et al. (2011) in detail.

Ecology

''Pseudunela viatoris'' is a minute species that lives in the spaces between sand grains in saltwater habitats, and it is thus considered to be a mesopsammic, marine interstitial animal that is part of the

meiofauna Meiobenthos, also called meiofauna, are small benthic invertebrates that live in both marine and fresh water environments. The term ''meiofauna'' loosely defines a group of organisms by their size, larger than microfauna but smaller than macrofau ...

of marine sands.

References

This article incorporates CC-BY-2.5 text from the reference

External links

* {{Taxonbar, from=Q12066532 Pseudunelidae Gastropods described in 2011