The mitotic stingaree (''Urolophus mitosis'') or blotched stingaree, 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 ...

, so named because it has light blue blotches on its back that resemble

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

s undergoing

mitotic division In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintai ...

. Though not uncommon, it is found only in a small area of 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 northwestern

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, at around down. This species attains a length of long and has a 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 with broadly rounded corners and a skirt-shaped curtain of skin between the nostrils. Its tail has subtle skin folds running along either side, 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 conv ...

, and a slender 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 ...

. 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 mitotic 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 little fishing within its range.

Taxonomy

The mitotic stingaree was described by Peter Last and Martin Gomon in a 1987 issue of ''Memoirs of the National Museum of Victoria'', in which they gave it 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 ...

''mitosis'' (derived from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''mitos'', meaning "thread") in reference to its unique color pattern. 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 female across, collected by the research

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 ...

er FRV ''Soela'' on 2 April 1982. A close relative is the brown stingaree (''U. westraliensis'').

Distribution and habitat

The mitotic stingaree has only been reported from a small area north of

Port Hedland A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Ham ...

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 ...

, where it is fairly common. This

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 ...

ray is found over fine

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...

at the edge of the

, around deep.

Description

The

disc of the mitotic stingaree is more or less diamond-shaped and slightly wider than long. The leading margins are nearly straight, while the outer corners and trailing margins are rounded. The snout forms an obtuse angle, with the tip extending slightly past the disc. The eyes are large and followed by the

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, which are comma-shaped with rounded or angular posterior rims. There may be a small knob on the posterior corner of each nostril. Between the nostrils is a skirt-shaped curtain of skin with a subtly fringed trailing margin, which is drawn out into lobes at either corner. The mouth is somewhat large with 3–4 papillae (nipple-like structures) on the floor; a few papillae are also present on the lower jaw. The teeth are small with roughly oval bases, and 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 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 slender tail is strongly flattened and bears a subtle skin fold along each side; it measures 85–104% as long as the disc. A serrated stinging spine is positioned atop the tail about halfway along its length; the

is elongated and lance-like. The skin is entirely smooth. The upper surface of the disc is light green, becoming reddish towards the margins, and adorned by several large, light blue blotches outlined and filled with tiny dots, such as that they resemble

cells Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

during

mitosis In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is mainta ...

. The blotches are variable in shape but evenly spaced. The underside and caudal fin are uniformly light. The largest known specimen measures long.

Biology and ecology

Virtually nothing is known of the natural history of the mitotic 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 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, like other stingrays. The litter size is probably small, as in related species. 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 definitio ...

at a length of .

Human interactions

The mitotic stingaree occurs within the management area of the North West Slope Trawl Fishery, but little actual fishing occurs within its range and this is unlikely to change in the future. Therefore, the

IUCN 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 ...

has listed this species under

. 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=Q3280952 mitotic stingaree Marine fish of Western Australia Taxa named by Peter R. Last Taxa named by Martin F. Gomon mitotic stingaree Taxonomy articles created by Polbot