The Java stingaree (''Urolophus javanicus'') 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 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 ...

, known only from a single female specimen long caught off Jakarta,

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

. This species is characterized by an oval-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 longer than wide, and a tail with 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 c ...

in front of the stinging spine and a

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 ...

. It is brown above, with darker and lighter spots. 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 ...

has listed the Java stingaree as critically endangered; it has not been recorded since its discovery over 150 years ago, and its range is subject to heavy fishing pressure and

habitat degradation Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

Taxonomy

In July 1862, German

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and d ...

Eduard von Martens Eduard von Martens (18 April 1831 – 14 August 1904) also known as ''Carl'' or ''Karl Eduard von Martens'', was a German zoologist. Born in Stuttgart in 1831, von Martens attended university in Tübingen, where he graduated in 1855. He then move ...

purchased the sole known specimen of the Java stingaree at a fish market in Jakarta. He described it as ''Trygonoptera javanica'' in an 1864 volume of the scientific journal ''Monatsberichte der Akademie der Wissenschaft zu Berlin'' (''Monthly Report of the Academy of Sciences, Berlin''). Subsequent authors moved this species to the genus ''Urolophus''.

Distribution and habitat

The Java stingaree has only been found off

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mos ...

, perhaps in the vicinity of Jakarta. Its exact range, and depth and

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

preferences, are unknown but probably very restricted.

Description

The Java stingaree has an oval

disc slightly longer than wide; the leading margins are gently convex and converge at a blunt angle on the snout. The eyes are followed by larger, comma-shaped spiracles. The nostrils are crescent-like, and between them is a curtain of skin with a minutely fringed posterior margin. The mouth is bow-shaped, and contains three papillae (nipple-like structures) on the floor. The teeth are closely arranged with a

quincunx A quincunx () is a geometric pattern consisting of five points arranged in a cross, with four of them forming a square or rectangle and a fifth at its center. The same pattern has other names, including "in saltire" or "in cross" in heraldry (d ...

pattern; each is small with a transverse ridge on the crown. 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 almost square, with rounded corners. The tail is shorter than the disc and bears a prominent

about halfway along its length; immediately posterior to the dorsal fin is a serrated stinging spine. The tail ends in a leaf-shaped

, whose dorsal origin lies behind the ventral origin. The skin is devoid of dermal denticles, though there are tiny white bumps on the upper central portion of the disc. This species is dark brown above, with many indistinct darker and lighter spots, and pale below. The sole specimen measures long.

Biology and ecology

Very little is known of the natural history of the Java 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 stingarees.

Human interactions

No new Java stingaree specimens have emerged since the first was discovered over 150 years ago, and it is feared to be extinct. There is heavy fishing activity within its range, as well as

from the proximity of major population centers. While it is possible that captured specimens have gone unrecognized, if this species still survives its population would almost certainly be gravely imperiled, leading the

(IUCN) to assess it as Critically Endangered.

References

{{DEFAULTSORT:stingaree, Java Java stingaree Fish of Indonesia Endemic fauna of Java Critically endangered fish Critically endangered fauna of Asia Taxonomy articles created by Polbot Taxa named by Eduard von Martens Java stingaree