The brown stingaree (''Urolophus westraliensis'') is a little-known

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 ...

stingray Stingrays are a group of sea rays, which are cartilaginous fish related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae ( ...

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 ...

Urolophidae The Urolophidae are a family of rays in the order Myliobatiformes, commonly known as stingarees or round stingrays. This family formerly included the genera '' Urobatis'' and ''Urotrygon'' of the Americas, which are presently recognized as formin ...

, found at a depth of on the outer

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

off northern

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

. This species has a rhomboid

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

disc colored light yellow or brown, sometimes with three faint, darker, transverse bars. Its nostrils have a skirt-shaped curtain of skin between them. Its tail ends in a leaf-shaped

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

and either lacks or has poorly developed lateral skin folds and a

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

. The maximum known length is . The

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

(IUCN) has listed the brown stingaree under

Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

, as there is negligible fishing pressure across most of its range.

Taxonomy

Peter Last and Martin Gomon described the brown stingaree in a 1987 issue of ''Memoirs of the National Museum of Victoria''. 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 ...

is a male across,

trawl Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different speci ...

ed from north of Port Hedland in Western Australia (hence the

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''westraliensis'') by the FRV ''Soela'' on 2 April 1982. This species is closely related to the

mitotic stingaree The mitotic stingaree (''Urolophus mitosis'') or blotched stingaree, is a little-known species of stingray in the family Urolophidae, so named because it has light blue blotches on its back that resemble cells undergoing mitotic division. Though ...

(''U. mitosis'').

Distribution and habitat

Endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to northern Western Australia, the brown stingaree is found over the outer

between the Dampier and

Bonaparte Archipelago The Bonaparte Archipelago is a group of islands off the coast of Western Australia in the Kimberley region, within the Shire of Wyndham-East Kimberley. The closest inhabited place is Kalumburu located about to the east of the island group. Th ...

s. It is a

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

species that has been reported from a depth of .

Description

The

disc of the brown stingaree is diamond-shaped and slightly wider than long, with broadly rounded outer corners. The anterior margins are nearly straight and converge at an obtuse angle on the snout, which protrudes slightly from the disc. The eyes are of modest size and followed by teardrop-shaped

spiracle Spiracle or spiraculum may refer to: * Spiracle (arthropods), opening in the exoskeletons of some arthropods * Spiracle (vertebrates), openings on the surface of some vertebrates * Spiraculum, a genus of land snails in family Cyclophoridae Cycl ...

s with rounded posterior rims. The outer rim of each nostril may form a knob at the back. Between the nostrils is skirt-shaped curtain of skin, with a posterior margin that is very shallowly fringed and extended into small lobes each corner. There are 5–6 small papillae (nipple-like structures) on the floor of the fairly large mouth, along with a few papillae on the lower jaw. The small teeth have roughly oval bases. The five pairs of

gill slit Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of cartilaginous fish such as sharks and rays, as well as deep-branching vertebrates such as lampreys. In con ...

s are short, and the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s are small and rounded. The tail is rather short, measuring 66–80% as long as the disc, with a serrated stinging spine on top about halfway along its length and a short, deep, leaf-shaped

at the end. There may be subtle traces of a lateral skin fold on either side and a

in front of the sting. The skin is completely smooth. The upper surface is light yellow or brown in adults and light yellow in juveniles; there may be faint, darker bars running across the eyes, the gill region, and the middle of the back. The underside is whitish, and the caudal fin is yellow with a black margin. The largest known specimen measures .

Biology and ecology

Little is known of the natural history of the brown stingaree. Reproduction is

aplacental viviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...

, with the developing

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

s sustained by histotroph ("uterine milk") produced by the mother. The litter size is probably small, as in related species. Newborns measure long; males

mature sexually Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definiti ...

at under long.

Human interactions

The range of the brown stingaree borders the area utilized by the North West Slope Trawl Fishery (NWSTF), but otherwise it faces no significant fishing pressure. Consequently, the

(IUCN) has listed this species under

. Its population may have been affected by intensive foreign

fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both ...

that operated in the region from 1959 to 1990. It would potentially benefit from the implementation of the 2004 Australian National Plan of Action for the Conservation and Management of Sharks.

References

{{Taxonbar, from=Q372059 brown stingaree Marine fish of Western Australia Taxonomy articles created by Polbot Taxa named by Peter R. Last Taxa named by Martin F. Gomon brown stingaree