The Chesterfield Island stingaree or Deforge's stingaree (''Urolophus deforgesi'') 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 ...

of stingray in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

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 formi ...

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 else ...

to the

continental slope A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...

off the

Chesterfield Islands The Chesterfield Islands (''îles Chesterfield'' in French) are a French archipelago of New Caledonia located in the Coral Sea, northwest of Grande Terre, the main island of New Caledonia. The archipelago is 120 km long and 70 km ...

. Reaching long, it has a rounded, diamond-shaped

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 plain brown above and pale below, with a short head. There is a narrow, skirt-shaped curtain of skin between its nostrils. Its tail is relatively long and terminates 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 ...

; there are no

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 c ...

or lateral skin folds. This species has been listed 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 ...

by 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 nat ...

(IUCN), as there is little fishing activity within its range.

Taxonomy

The first known specimens of the Chesterfield Island stingaree were caught during a series of research cruises undertaken in the Coral Sea by France and Australia in the 1990s. The species was described by Bernard Séret and Peter Last in a 2003 issue of the scientific journal ''Cybium'', and named for Institut de Recherche pour le Développement (IRD) scientist Bertrand Richer de Forges. The

type specimen In biology, a type is a particular 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 anchor or centralizes th ...

is a long adult male collected by the research vessel ''Coriolis''. This species is closely related to the New Caledonian stingaree (''U. neocaledoniensis''), and also bears morphological similarities to the mitotic stingaree (''U. mitosis'').

Distribution and habitat

The range of the Chesterfield Island stingaree is limited to the

, northwest of New Caledonia. This bottom-dwelling ray inhabits the

over a depth range of .

Description

The

disc of the Chesterfield Island stingaree is diamond-shaped and 109–122% as wide as long, with broadly rounded outer corners and gently convex leading margins. The snout is fleshy and forms an obtuse angle, with the tip slightly protruding. The eyes are medium-sized and somewhat closely spaced, and immediately followed by teardrop-shaped spiracles. There is a narrow, skirt-shaped curtain of skin between the nostrils, with a deeply fringed posterior margin and the posterior corners drawn out into lobes. The mouth is modestly sized and contains 7–8 papillae (nipple-like structures) on the floor, arranged in a "W"; there is also a patch of small papillae on the lower jaw. There are 28–33 upper tooth rows and 27–31 lower tooth rows. 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. The pelvic fins are small and rounded; males have slender, pointed

clasper In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating. Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin which serve to channel semen into the female's c ...

s. The tail is somewhat flattened and measures 77–84% as long as the disc. There is a single dorsally placed, serrated stinging spine around halfway along the tail, and no

or lateral skin folds. The tail terminates in a long, low, leaf-shaped

. The skin is entirely devoid of dermal denticles. This species is plain yellowish brown above with a dark caudal fin margin, which is more obvious in juveniles. The underside is white to cream, darkening slightly at the fin margins. The largest known specimen is long.

Biology and ecology

Little is known of the natural history of the Chesterfield Island stingaree. It is presumably

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 ins ...

with a small litter size, as in other members of its family. Newborns measure around long and males reach

sexual maturity 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 definit ...

at under long.

Human interactions

The

(IUCN) has listed the Chesterfield Island stingaree under

, as no

commercial Commercial may refer to: * a dose of advertising conveyed through media (such as - for example - radio or television) ** Radio advertisement ** Television advertisement * (adjective for:) commerce, a system of voluntary exchange of products and s ...

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 ...

fishing Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from stocked bodies of water such as ponds, canals, park wetlands and reservoirs. Fishing techniques inclu ...

occurs within its range.

References

{{Taxonbar, from=Q3282192 Urolophus Fish of New Caledonia Taxonomy articles created by Polbot Taxa named by Bernard Séret Taxa named by Peter R. Last Fish described in 2003