Wide stingaree
Encyclopedia
The wide stingaree is a little-known species
of stingray
in the family
Urolophidae, found off southwestern Australia
. It typically occurs over sand in water 200–300 m (656.2–984.3 ft) deep around the edge of the continental shelf
. This species has a broad diamond-shaped pectoral fin disc, a slightly pointed snout, and a tail with a leaf-like caudal fin, skin folds along either side, and no dorsal fin
s. Between its nostrils is a skirt-shaped curtain of skin. It is grayish green above, with faint bluish lines beside and behind the eyes. The maximum length on record is 52 cm (20.5 in).
The diet of the wide stingaree consists mainly of isopods and polychaete worms. It is aplacental viviparous, with the females supplying their unborn young with histotroph ("uterine
milk"). This species is regularly caught incidentally
by commercial trawl fisheries operating in the Great Australian Bight
. Although it is unlikely to survive being captured and also tends to abort any gestating young during the process, large portions of the wide stingaree's range see little to no fishing activity and overall the species is not threatened. The International Union for Conservation of Nature (IUCN) has listed it under Least Concern
.
by the research vessel FIS Endeavour, and described by Australian ichthyologist Alan Riverstone McCulloch
in an 1916 volume of the scientific journal
Biological Results Endeavour. The specific epithet expansus means "spread out" or "expanded" in Latin
. Another common name
for this species is broadbacked stingaree.
to Port Lincoln, South Australia
. One of the deeper-living representatives of its family, this benthic species inhabits the outer continental shelf
and upper continental slope at a depth of 130–420 m (426.5–1,378 ft). It is most commonly found between 200 and 300 m (656.2 and 984.3 ft) down, over sandy areas. There is evidence for some degree of segregation by age and sex.
s with rounded posterior margins. There is a skirt-shaped curtain of skin with a shallowly fringed posterior margin between the nostrils. The mouth is of medium size and contains 6–9 papillae (nipple-like structures) on the floor; a narrow patch of papillae is also found on the lower jaw. The teeth are small with roughly oval bases. The five pairs of gill slit
s are short. The pelvic fins are small, with rounded edges.
The tail measures 71–93% as long as the disc and has a highly flattened base and well-developed lateral skin folds; there is no dorsal fin
, while the terminal caudal fin is lance-like and elongated. A serrated stinging spine is placed atop the tail about halfway along its length. The skin is completely smooth. This species is dusky green above, with two faint, bluish transverse lines behind the eyes and a pair of similar lines running obliquely outwards from the eyes. The underside is white to beige, darkening towards the disc lateral margins, with dark blotches on the tail. Juveniles have a dark caudal fin. The largest known specimen measures 52 cm (20.5 in) long.
s sustained by histotroph ("uterine
milk"). The litter size is probably small as in related species. Males mature sexually
at a disc width of 30–36 cm (11.8–14.2 in) and seven years of age, and have a maximum lifespan of 11 years. Females mature at a disc width of about 40 cm (15.7 in). A known parasite of this species is a tapeworm of the genus Acanthobothrium.
on a regular basis in otter trawls utilized by the Great Australian Bight Trawl Sector of the Southern and Eastern Scalefish and Shark Fishery (SESSF), and to a much lesser extent by the small-scale Western Deepwater Trawl Fishery (WDWTF) in the westernmost portion of its range. Captured individuals are unlikely to survive as they are brought up from such great depths, and furthermore stingarees have a tendency to abort their young when captured. However, the SESSF only operates over part of the Great Australian Bight, and so the overall level of fishing pressure across the wide stingaree's range is low. Therefore, the International Union for Conservation of Nature (IUCN) has assessed this species as of Least Concern
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of stingray
Myliobatiformes
Myliobatiformes is one of the four orders of batoids, cartilaginous fishes related to sharks. They were formerly included in the order Rajiformes, but more recent phylogenetic studies have shown that the myliobatiforms are a monophyletic group, and that its more derived members evolved their...
in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Urolophidae, found off southwestern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. It typically occurs over sand in water 200–300 m (656.2–984.3 ft) deep around the edge of the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
. This species has a broad diamond-shaped pectoral fin disc, a slightly pointed snout, and a tail with a leaf-like caudal fin, skin folds along either side, and no dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
s. Between its nostrils is a skirt-shaped curtain of skin. It is grayish green above, with faint bluish lines beside and behind the eyes. The maximum length on record is 52 cm (20.5 in).
The diet of the wide stingaree consists mainly of isopods and polychaete worms. It is aplacental viviparous, with the females supplying their unborn young with histotroph ("uterine
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
milk"). This species is regularly caught incidentally
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
by commercial trawl fisheries operating in the Great Australian Bight
Great Australian Bight
The Great Australian Bight is a large bight, or open bay, off the central and western portions of the southern coastline of mainland Australia.-Extent:...
. Although it is unlikely to survive being captured and also tends to abort any gestating young during the process, large portions of the wide stingaree's range see little to no fishing activity and overall the species is not threatened. The International Union for Conservation of Nature (IUCN) has listed it under Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
.
Taxonomy
The first known specimens of the wide stingaree were collected from the Great Australian BightGreat Australian Bight
The Great Australian Bight is a large bight, or open bay, off the central and western portions of the southern coastline of mainland Australia.-Extent:...
by the research vessel FIS Endeavour, and described by Australian ichthyologist Alan Riverstone McCulloch
Alan Riverstone McCulloch
Alan Riverstone McCulloch was a prominent Australian ichthyologist.McCulloch was born in Sydney, and began his scientific career at the age of 13 as an unpaid assistant to Edgar Ravenswood Waite in the Australian Museum there; Waite encouraged McCulloch to study zoology...
in an 1916 volume of the scientific journal
Scientific journal
In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. There are thousands of scientific journals in publication, and many more have been published at various points in the past...
Biological Results Endeavour. The specific epithet expansus means "spread out" or "expanded" in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
. Another common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
for this species is broadbacked stingaree.
Distribution and habitat
The wide stingaree is endemic to southwestern Australia, occurring from Perth, Western AustraliaPerth, Western Australia
Perth is the capital and largest city of the Australian state of Western Australia and the fourth most populous city in Australia. The Perth metropolitan area has an estimated population of almost 1,700,000....
to Port Lincoln, South Australia
Port Lincoln, South Australia
- Transport :Port Lincoln is the port for the isolated narrow gauge Eyre Peninsular Railway.There is also a subsidiary port at Proper Bay which may be restored to use for iron ore traffic. The export of iron ore through Port Lincoln has been approved by the South Australian Government. Port...
. One of the deeper-living representatives of its family, this benthic species inhabits the outer continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
and upper continental slope at a depth of 130–420 m (426.5–1,378 ft). It is most commonly found between 200 and 300 m (656.2 and 984.3 ft) down, over sandy areas. There is evidence for some degree of segregation by age and sex.
Description
The wide stingaree has a diamond-shaped pectoral fin disc much wider than long, with broadly rounded outer corners and trailing margins. The anterior margins are gently sinuous and converge at an obtuse angle on the fleshy, slightly protruding snout. The eyes are large and immediately followed by comma-shaped spiracleSpiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
s with rounded posterior margins. There is a skirt-shaped curtain of skin with a shallowly fringed posterior margin between the nostrils. The mouth is of medium size and contains 6–9 papillae (nipple-like structures) on the floor; a narrow patch of papillae is also found on the lower jaw. The teeth are small with roughly oval bases. The five pairs of gill slit
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, rays, sawfish, and guitarfish. Most of these have five pairs, but a few species have 6 or 7 pairs...
s are short. The pelvic fins are small, with rounded edges.
The tail measures 71–93% as long as the disc and has a highly flattened base and well-developed lateral skin folds; there is no dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
, while the terminal caudal fin is lance-like and elongated. A serrated stinging spine is placed atop the tail about halfway along its length. The skin is completely smooth. This species is dusky green above, with two faint, bluish transverse lines behind the eyes and a pair of similar lines running obliquely outwards from the eyes. The underside is white to beige, darkening towards the disc lateral margins, with dark blotches on the tail. Juveniles have a dark caudal fin. The largest known specimen measures 52 cm (20.5 in) long.
Biology and ecology
The wide stingaree is a poorly known species that preys mainly on isopods and polychaete worms. Like other stingrays, it is aplacental viviparous, with the developing embryoEmbryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s sustained by histotroph ("uterine
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
milk"). The litter size is probably small as in related species. Males mature sexually
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at a disc width of 30–36 cm (11.8–14.2 in) and seven years of age, and have a maximum lifespan of 11 years. Females mature at a disc width of about 40 cm (15.7 in). A known parasite of this species is a tapeworm of the genus Acanthobothrium.
Human interactions
Edible though not marketed, the wide stingaree is caught incidentallyBycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
on a regular basis in otter trawls utilized by the Great Australian Bight Trawl Sector of the Southern and Eastern Scalefish and Shark Fishery (SESSF), and to a much lesser extent by the small-scale Western Deepwater Trawl Fishery (WDWTF) in the westernmost portion of its range. Captured individuals are unlikely to survive as they are brought up from such great depths, and furthermore stingarees have a tendency to abort their young when captured. However, the SESSF only operates over part of the Great Australian Bight, and so the overall level of fishing pressure across the wide stingaree's range is low. Therefore, the International Union for Conservation of Nature (IUCN) has assessed this species as of Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
.