Striped stingaree
Encyclopedia
The striped stingaree (Trygonoptera ovalis) is a common but little-known species
of stingray
in the family
Urolophidae, endemic to shallow, inshore waters off southwestern Australia
. Reaching 61 cm (24 in) long, this species is characterized by an oval, grayish to brownish disc with darker mask-like markings around the eyes and paired blotches at the center of the disc that are extended posteriorly into horizontal lines. Its nostrils have enlarged lobes on the outer margins and a skirt-shaped curtain of skin with a deeply fringed trailing margin in between. Its tail terminates in a relatively large leaf-shaped caudal fin, and bears a small dorsal fin
just before the stinging spine. The rounded, flexible disc of the striped stingaree enable it to maneuver through the rocks, reef
s, and seagrass
that comprise its favored habitat
s. The International Union for Conservation of Nature (IUCN) has listed this species under Least Concern
; it is seldom caught by fisheries due to its habitat preferences.
and refers to its shape. The type specimen, a female 21 cm (8.3 in) across, was trawled from the Great Australian Bight
, south of Red Rocks Point, by the FRV Courageous on 3 March 1978. Other common name
s for this species include bight stingaree and oval stingaree.
, from Eucla to the Houtman Abrolhos
, at a depth of 1–43 m (3.3–141.1 ft). This common, bottom-dwelling ray favors rocky areas and reef
s, often in and around seagrass
beds, and has also been observed over sand near beaches.
s with angular posterior rims. The outer rims of the nostrils are enlarged into prominent lobes. Between the nostrils is a skirt-shaped curtain of skin with long fringes on the posterior margin, that overhang the small mouth. There are numerous papillae (nipple-like structures) on the lower jaw, while four tiny papillae are found on the floor of the mouth. The small teeth have roughly oval bases. The five pairs of gill slit
s are short.
The pelvic fins are small and rounded. The tail measures 75–100% as long as the disc and is oval in cross-section; it is slightly flattened at the base and terminates in a fairly large, deep, leaf-shaped caudal fin. The upper surface of the tail mounts a serrated stinging spine, which is immediately preceded by a small dorsal fin
; there are no lateral fin folds. The skin is entirely smooth. The dorsal coloration of this species is distinctive: on a grayish to grayish brown background, there is a dark mask-like pattern around the eyes that may extend to the tip of the snout (most obvious in juveniles), as well as a pair of dark blotches at the center of the disc that are drawn out posteriorly into stripes that run onto the tail; the area between the stripes is relatively light. The dark markings may be faint in some individuals. The underside is pale with dark margins on the fins, and the caudal fin is gray or black with a darker trailing margin. The maximum known length is 61 cm (24 in).
at around 35 cm (13.8 in) long.
. A few are caught incidentally
by the small numbers of scallop
and prawn
trawler
s operating within its range, but this species is largely shielded from their activities by its preference for rough terrain. It would potentially benefit from the implementation of the 2004 Australian National Plan of Action for the Conservation and Management of Sharks.
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, endemic to shallow, inshore waters 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...
. Reaching 61 cm (24 in) long, this species is characterized by an oval, grayish to brownish disc with darker mask-like markings around the eyes and paired blotches at the center of the disc that are extended posteriorly into horizontal lines. Its nostrils have enlarged lobes on the outer margins and a skirt-shaped curtain of skin with a deeply fringed trailing margin in between. Its tail terminates in a relatively large leaf-shaped caudal fin, and bears a small 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...
just before the stinging spine. The rounded, flexible disc of the striped stingaree enable it to maneuver through the rocks, reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s, and seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
that comprise its favored habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s. The International Union for Conservation of Nature (IUCN) has listed this species 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...
; it is seldom caught by fisheries due to its habitat preferences.
Taxonomy
The striped stingaree was described by Peter Last and Martin Gomon in a 1987 issue of Memoirs of the National Museum of Victoria; its specific epithet ovalis means "oval" in LatinLatin
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...
and refers to its shape. The type specimen, a female 21 cm (8.3 in) across, was trawled from 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:...
, south of Red Rocks Point, by the FRV Courageous on 3 March 1978. Other 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...
s for this species include bight stingaree and oval stingaree.
Distribution and habitat
The striped stingaree is found only along the coast of Western AustraliaWestern Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
, from Eucla to the Houtman Abrolhos
Houtman Abrolhos
The Houtman Abrolhos is a chain of 122 islands, and associated coral reefs, in the Indian Ocean off the west coast of Australia. Nominally located at , it lies about eighty kilometres west of Geraldton, Western Australia...
, at a depth of 1–43 m (3.3–141.1 ft). This common, bottom-dwelling ray favors rocky areas and reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s, often in and around seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
beds, and has also been observed over sand near beaches.
Description
More so than any other member of its genus, the pectoral fin disc of the striped stingaree is oval in shape. The disc is slightly longer than wide, with the anterior margins converging at an obtuse angle on the rounded, non-protruding tip of the fleshy snout. The medium-sized eyes are 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 angular posterior rims. The outer rims of the nostrils are enlarged into prominent lobes. Between the nostrils is a skirt-shaped curtain of skin with long fringes on the posterior margin, that overhang the small mouth. There are numerous papillae (nipple-like structures) on the lower jaw, while four tiny papillae are found on the floor of the mouth. The small teeth have 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 and rounded. The tail measures 75–100% as long as the disc and is oval in cross-section; it is slightly flattened at the base and terminates in a fairly large, deep, leaf-shaped caudal fin. The upper surface of the tail mounts a serrated stinging spine, which is immediately preceded by a small 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...
; there are no lateral fin folds. The skin is entirely smooth. The dorsal coloration of this species is distinctive: on a grayish to grayish brown background, there is a dark mask-like pattern around the eyes that may extend to the tip of the snout (most obvious in juveniles), as well as a pair of dark blotches at the center of the disc that are drawn out posteriorly into stripes that run onto the tail; the area between the stripes is relatively light. The dark markings may be faint in some individuals. The underside is pale with dark margins on the fins, and the caudal fin is gray or black with a darker trailing margin. The maximum known length is 61 cm (24 in).
Biology and ecology
The smoothly rounded, flexible margins of the striped stingaree's disc give it superior agility compared to most other rays, allowing it to dart unencumbered through structurally complex terrain and vegetation. It often seeks shelter beneath patches of seagrass, but has also been observed resting in the open or buried in sand. Little is known of its natural history. Reproduction is presumably aplacental viviparous like other stingrays; males attain sexual maturitySexual 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 around 35 cm (13.8 in) long.
Human interactions
The International Union for Conservation of Nature (IUCN) has assessed the striped stingaree as of Least ConcernLeast 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...
. A few are 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 the small numbers of scallop
Scallop
A scallop is a marine bivalve mollusk of the family Pectinidae. Scallops are a cosmopolitan family, found in all of the world's oceans. Many scallops are highly prized as a food source...
and prawn
Prawn
Prawns are decapod crustaceans of the sub-order Dendrobranchiata. There are 540 extant species, in seven families, and a fossil record extending back to the Devonian...
trawler
Trawler
A fishing trawler is a commercial fishing vessel designed to operate fishing trawls. Trawling is a method of fishing that involves actively dragging or pulling a trawl through the water behind one or more trawlers. Trawls are fishing nets that are pulled along the bottom of the sea or in midwater...
s operating within its range, but this species is largely shielded from their activities by its preference for rough terrain. It would potentially benefit from the implementation of the 2004 Australian National Plan of Action for the Conservation and Management of Sharks.