Lobed stingaree

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Lobed stingaree
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Batoidea
Order: Myliobatiformes
Family: Urolophidae
Genus: Urolophus
Species:
U. lobatus
Binomial name
Urolophus lobatus
McKay, 1966

The lobed stingaree (Urolophus lobatus) is a common species of stingray in the family Urolophidae, endemic to southern Western Australia in shallow, inshore sand and seagrass habitats. This species is plain sandy in colour above and has a broad, rounded pectoral fin disc. It is characterized by an enlarged, semicircular skin lobe of unknown function on the inner rim of each nostril. Its tail is slender, with lateral skin folds and a lance-like caudal fin but no dorsal fin. The maximum recorded width is 27 cm (11 in).

Contents

A benthic predator, the lobed stingaree feeds mostly on crustaceans, and to a much lesser extent on small bony fishes, polychaete worms, and molluscs. It is aplacental viviparous, with females typically bearing a single pup every October or November after a gestation period of ten months. Developing embryos are nourished by maternally produced histotroph ("uterine milk") after they exhaust their supply of yolk. In the northern portion of its range, the lobed stingaree is frequently caught incidentally by trawlers. Though it generally survives the experience, it has a tendency to abort its young when captures. However, this species is not greatly affected by human activity overall, and it has been listed under Least Concern by the International Union for Conservation of Nature (IUCN).

Taxonomy

Australian ichthyologist Roland McKay described the lobed stingaree in a 1966 issue of the Journal of the Royal Society of Western Australia, giving it the specific epithet lobatus in reference to its unique nasal lobes. The type specimen was collected from a depth of 31–33 m (102–108 ft) northeast of Rottnest Island off Western Australia. [2]

Distribution and habitat

Among the most abundant representatives of its family within its range, [3] the lobed stingaree is found along a short stretch of the southwest Australian coast from Esperance to Rottnest Island. [4] This bottom-dwelling species favors sandy flats and seagrass beds, from the intertidal zone to a depth of 30 m (98 ft). [1] In the southern portion of its range, it tends to be found relatively far from shore. Individuals of different ages and sexes are not segregated from each other. [3]

Description

The lobed stingaree has a rounded pectoral fin disc much wider than long, with nearly straight leading margins. The snout is fleshy and forms an obtuse angle; the tip may protrude slightly past the disc. The medium-sized eyes are followed by teardrop-shaped spiracles, which have a rounded posterior margin. The outer posterior corner of each nostril forms a visible lobe. Between the nostrils is a skirt-shaped curtain of skin with a fringed trailing margin; the front corners of the curtain are enlarged into distinctive, semicircular lobes. The mouth is small and contains 9–10 papillae (nipple-like structures) on the floor; a handful of papillae are also found on the lower jaw. [4] The small teeth have roughly oval bases. The five pairs of gill slits are short. The pelvic fins are small and rounded. [5]

The tail is slender and very flattened, measuring 87–100% as long as the disc and bearing a prominent horizontal skin fold on either side. There is a dorsally positioned, serrated stinging spine near the caudal fin, which is long, narrow, and leaf-shaped. There is no dorsal fin. The skin entirely lacks dermal denticles. This species is yellowish brown above, becoming slightly lighter at the lateral margins of the side, and white below; some individuals have irregular blotches and/or a dark stripe along the dorsal midline of the tail. The caudal fin becomes dark towards the tip. [4] Males and females can grow up to 24 cm (9.4 in) and 27 cm (11 in) across respectively. [1]

Biology and ecology

Almost 90% of the food volume consumed by the lobed stingaree consists of crustaceans, in particular mysids, amphipods, shrimps, and cumaceans, which are captured on or just above the bottom. This species also feeds on polychaete worms, small bony fishes, and rarely molluscs. Rays smaller than 19 cm (7.5 in) across take relatively more mysids, amphipods, and cumaceans, while larger rays take more shrimps and fishes, and have a more diverse diet overall. Its dietary composition also shifts seasonally, mostly reflecting the greater availability of shrimp in summer and fall and cumaceans in winter and spring. [3] [6] A known parasite of this species is a tapeworm in the genus Acanthobothrium. [7] The function of its unique nasal lobes is unknown. [4]

Like other stingrays, the lobed stingaree is aplacental viviparous. Females have a single functional uterus, on the left, and an annual reproductive cycle. Mating occurs in November and October and ovulation from mid-November and mid-January, implying that the females store sperm internally for 1–3 months before fertilization. The gestation period lasts ten months; although up to six eggs may be fertilized, usually only a single pup (rarely two) develops to term. The embryo is initially nourished by an external yolk sac; by five months of age, the embryo measures 5.4 cm (2.1 in) across and has transferred most of the remaining yolk into its digestive tract. By six months of age, the mother begins to deliver nutrient-rich histotroph ("uterine milk") through thread-like extensions of the uterine epithelium called "trophonemata", which grow into the mouth, gills, and spiracles of the embryo. The disc and tail of the embryo are folded to hug the sting next to the body. Birthing occurs in late October or early November, with the newborns measuring around 11 cm (4.3 in) across. Females grow more slowly and to a larger ultimate size than males. Sexual maturity is reached by males at around 16 cm (6.3 in) across and two years of age, and by females at around 20 cm (7.9 in) across and three years of age. The maximum lifespan is 12 and 14 years for males and females respectively. [1] [8]

Human interactions

The lobed stingaree is often caught incidentally by scallop and prawn trawlers operating off Perth and Mandurah in the northern part of its range. It usually survives to be released alive, though stingarees have a tendency to abort their young upon capture. As the number of vessels that catch this species is small, and it faces no other significant conservation threats within its range, the International Union for Conservation of Nature (IUCN) has assessed the lobed stingaree as of Least Concern. It would potentially benefit from the implementation of the 2004 Australian National Plan of Action for the Conservation and Management of Sharks. [1]

Related Research Articles

<span class="mw-page-title-main">Urolophidae</span> Family of cartilaginous fishes

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 forming their own family Urotrygonidae. Stingarees are found in the Indo-Pacific region, with the greatest diversity off Australia. They are sluggish, bottom-dwelling fish that have been recorded from shallow waters close to shore to deep waters over the upper continental slope. Measuring between 15 and 80 cm long, these rays have oval to diamond-shaped pectoral fin discs and relatively short tails that terminate in leaf-shaped caudal fins, and may also have small dorsal fins and lateral skin folds. Most are smooth-skinned, and some have ornate dorsal color patterns.

<span class="mw-page-title-main">Western shovelnose stingaree</span> Species of cartilaginous fish

The western shovelnose stingaree is a common species of stingray in the family Urolophidae, inhabiting shallow sandy flats and seagrass beds off southwestern Australia from Perth to Gulf St Vincent. Growing to 37 cm (15 in) long, this small ray has a rounded pectoral fin disc and a blunt, broadly triangular snout. Its nostrils have enlarged lobes along the outer rims and a skirt-shaped curtain of skin between them with a strongly fringed posterior margin. Its tail ends in a lance-like caudal fin and lacks dorsal fins and lateral skin folds. This species is colored grayish to brownish above, sometimes with lighter and darker spots, and pale below, sometimes with darker marginal bands and blotches.

<span class="mw-page-title-main">Striped stingaree</span> Species of cartilaginous fish

The striped stingaree 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, reefs, and seagrass that comprise its favored habitats. 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.

The masked stingaree is a common species of stingray in the family Urolophidae, endemic to southwestern Australia. It prefers moderately deep areas of sand or seagrass some distance from shore, though it can be found in very shallow water or to a depth of 115 m (377 ft). The masked stingaree can be identified by the two large, dark blotches on the upper surface of its rounded pectoral fin disc, one of which encompasses its eyes like a mask. The outer rims of its nostrils are expanded into prominent lobes, while between the nostrils is a skirt-like curtain of skin with a deeply fringed trailing margin. Its tail bears a small dorsal fin just before the stinging spine, and end in a leaf-like caudal fin. This species grows up to 31 cm (12 in) across.

<span class="mw-page-title-main">Eastern shovelnose stingaree</span> Species of cartilaginous fish

The eastern shovelnose stingaree is a species of stingray in the family Urolophidae, endemic to coastal waters off southeastern Australia, excluding Tasmania. This species has a rounded pectoral fin disc wider than long, a fleshy snout forming an obtuse angle, and a relatively short tail terminating in a caudal fin. Its nostrils have prominent lobes on their outside rims and a skirt-shaped curtain of skin with a strongly fringed trailing margin between them. The dorsal coloration is mostly plain brownish, occasionally with a scattering of darker and/or lighter spots. One of the larger stingarees, it can grow to at least 80 cm (31 in) long.

<span class="mw-page-title-main">Common stingaree</span> Species of cartilaginous fish

The common stingaree is a species of stingray in the family Urolophidae. The most abundant ray in inshore waters off eastern Australia, it generally inhabits estuaries, sandy flats, and rocky reefs from the shore to a depth of 60 m (200 ft). This plain brownish to grayish species has a rounded pectoral fin disc with a broadly triangular snout. Its nostrils have enlarged lobes on their outer margins and a skirt-shaped curtain of skin with a fringed posterior margin between them. Its tail bears a small dorsal fin before the stinging spine, and terminates in a leaf-shaped caudal fin. This ray can grow to 52 cm (20 in) long.

The New Ireland stingaree or black-spotted stingaree, is a species of stingray in the family Urolophidae, known only from a single juvenile male 17.4 cm (6.9 in) long, collected in the Bismarck Archipelago. This species has an oval pectoral fin disc with tiny eyes and a rectangular curtain of skin between the nostrils. Its tail is fairly long and terminates in a leaf-shaped caudal fin, and lacks a dorsal fin. Uniquely among stingarees, it has rows of sharp spinules on the posterior portion of its back and the base of its tail. Its dorsal coloration is brown with dark spots. The International Union for Conservation of Nature (IUCN) has listed this ray as Data Deficient, pending more information.

<span class="mw-page-title-main">Sandyback stingaree</span> Species of cartilaginous fish

The sandyback stingaree or great stingaree is a little-known species of stingray in the family Urolophidae, endemic to southeastern Australia. It is generally found offshore around the edge of the continental shelf, at a depth of 65–265 m (213–869 ft). A relatively large species reaching 89 cm (35 in) long, the sandyback stingaree has a diamond-shaped pectoral fin disc wider than long, usually with a dorsal pattern of numerous fine lighter marks on a yellowish to brownish background. Its short tail terminates in a deep, leaf-shaped caudal fin, and bears a sizable dorsal fin just in front of the stinging spine.

The circular stingaree is an uncommon, little-known species of stingray in the family Urolophidae. Endemic to the coastal waters of southwestern Australia, it prefers a rocky and/or vegetated habitat. Reaching 60 cm (24 in) in length, this species is characterized by an oval pectoral fin disc bearing a striking dorsal pattern of lighter spots and rings, and a central circle of white-margined black spots, on a bluish gray background. Between its nostrils is a skirt-shaped curtain of skin, with the posterior corners drawn out into lobes. Its tail bears a rather large dorsal fin in front of the stinging spine, and ends in a deep, lance-like caudal fin. Negligibly affected by human activity, the circular stingaree has been listed under Least Concern by the International Union for Conservation of Nature (IUCN).

<span class="mw-page-title-main">Crossback stingaree</span> Species of cartilaginous fish

The crossback stingaree or banded stingaree is a species of stingray in the family Urolophidae. It is endemic to southeastern Australia, mainly off Victoria and Tasmania but also marginally to New South Wales and South Australia. This bottom-dwelling fish generally inhabits sand and reef habitats deeper than 100 m (330 ft) off Victoria, and muddy habitats in shallow bays and estuaries off Tasmania. Befitting its name, the crossback stingaree has a distinctive dark pattern on its back, consisting of a midline stripe that is crossed by three transverse bars. It has an oval pectoral fin disc with a blunt snout and a skirt-shaped curtain of skin between the nostrils. Its tail is short with no skin fold along the sides, and a deep, leaf-shaped caudal fin. The youngest rays may have a small dorsal fin in front of the stinging tail spine. This species reaches 50 cm (20 in) in length.

The Chesterfield Island stingaree or Deforge's stingaree is a little-known species of stingray in the family Urolophidae, endemic to the continental slope off the Chesterfield Islands. Reaching 34 cm (13 in) long, it has a rounded, diamond-shaped pectoral fin 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; there are no dorsal fin or lateral skin folds. This species has been listed under Least Concern by the International Union for Conservation of Nature (IUCN), as there is little fishing activity within its range.

<span class="mw-page-title-main">Wide stingaree</span> Species of cartilaginous fish

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 (660–980 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 fins. 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 in).

The patchwork stingaree is a little-known species of stingray in the family Urolophidae, with a disjunct distribution off northwestern and northeastern Australia. It usually inhabits the outer continental shelf, at a depth of 60–320 m (200–1,050 ft). This species has a diamond-shaped pectoral fin disc much wider than long, and a short, flattened tail with a prominent dorsal fin and leaf-like caudal fin. There is a skirt-shaped curtain of skin between its nostrils. Its dorsal colour pattern resembles a mosaic of dark brown rings with light-coloured centers, separated by fine reticulated lines. The International Union for Conservation of Nature (IUCN) has listed the patchwork stingaree under Least Concern, as it is subject to minimal fishing pressure.

<span class="mw-page-title-main">Spotted stingaree</span> Species of cartilaginous fish

The spotted stingaree is an uncommon species of stingray in the family Urolophidae, endemic to shallow waters along the coast of southern Australia. It favors rocky reefs and seagrass beds. This species can be readily identified by its nearly circular, dark-colored pectoral fin disc, adorned with a complex pattern of white or cream spots. Its eastern and western forms differ slightly in coloration and have been regarded as separate species. There is a skirt-shaped curtain of skin between its nostrils. Its tail is fairly thick and terminates in a short leaf-shaped caudal fin; a relatively large dorsal fin is present just in front of the stinging spine.

The mitotic stingaree or blotched stingaree, is a little-known species of stingray in the family Urolophidae, so named because it has light blue blotches on its back that resemble cells undergoing mitotic division. Though not uncommon, it is found only in a small area of the outer continental shelf off northwestern Australia, at around 200 m (660 ft) down. This species attains a length of 29 cm (11 in) long and has a diamond-shaped pectoral fin 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, and a slender leaf-shaped caudal fin. The International Union for Conservation of Nature (IUCN) has listed the mitotic stingaree under Least Concern, as there is little fishing within its range.

<span class="mw-page-title-main">Sparsely spotted stingaree</span> Species of cartilaginous fish

The sparsely spotted stingaree, also known as the white-spotted stingaree or Dixon's stingaree, is a species of stingray in the family Urolophidae, common off the southern Australian coast. Preferring sandy flats and seagrass beds, this benthic ray can be found from close to shore to a depth of at least 150 m (490 ft), and tends to occur deeper in the northern portion of its range. Reaching a length of 57 cm (22 in), this species has a broad, diamond-shaped pectoral fin disc that is typically plain gray in color above with a V-shaped marking between the eyes. Individuals from southerly waters also generally exhibit a smattering of small, dark-edged white spots. This ray is further characterized by a distinctively bell-shaped curtain of skin between the nostrils. Its tail has a skin fold running along either side and a leaf-shaped caudal fin, but no dorsal fin.

The Coral Sea stingaree is a little-known species of stingray in the family Urolophidae, found at a depth of 171–310 m (561–1,017 ft) around the edge of the continental shelf off northern Queensland. Growing to a length of 48 cm (19 in), this species has a diamond-shaped pectoral fin disc with a protruding snout and a skirt-shaped flap of skin between the nostrils. Its tail bears a low dorsal fin before the stinging spine and terminates in a short leaf-shaped caudal fin. Its upper surface is grayish or brownish, sometimes with tiny dark spots. The Coral Sea stingaree may represent two closely similar species, one large and one small. There is very little fishing activity within its range, and thus it has been listed under Least Concern by the International Union for Conservation of Nature (IUCN).

<span class="mw-page-title-main">Kapala stingaree</span> Species of cartilaginous fish

The Kapala stingaree is a species of stingray in the family Urolophidae, endemic to inshore waters off southeastern Queensland and New South Wales. It is commonly found on and around rocky reefs at a depth of 10–130 m (33–427 ft). Reaching 51 cm (20 in) in length, the Kapala stingaree has a rounded, diamond-shaped pectoral fin disc and a slender tail, which ends in a leaf-shaped caudal fin and bears lateral skin folds and a small dorsal fin in front of the stinging spine. It has a distinctive bell-shaped curtain of skin between its nostrils. This species is greenish above, with a highly variable pattern of dark markings usually found outside and between the eyes, and over the back and tail.

<span class="mw-page-title-main">Greenback stingaree</span> Species of cartilaginous fish

The greenback stingaree is a little-known species of stingray in the family Urolophidae, endemic to the outer continental shelf and upper continental slope off southeastern Australia. Growing to a length of 51 cm (20 in), this species has a diamond-shaped pectoral fin disc wider than long and uniformly light green in color above. Between its nostrils is a skirt-shaped curtain of skin. Its tail bears skin folds on either side and a deep, lanceolate caudal fin, but lacks a dorsal fin.

The brown stingaree is a little-known species of stingray in the family Urolophidae, found at a depth of 60–220 m (200–720 ft) on the outer continental shelf off northern Western Australia. This species has a rhomboid pectoral fin disc colored light yellow or brown, sometimes with three faint, darker, transverse bars. Its nostrils have a skirt-shaped curtain of skin between them. Its tail ends in a leaf-shaped caudal fin and either lacks or has poorly developed lateral skin folds and a dorsal fin. The maximum known length is 36 cm (14 in). The International Union for Conservation of Nature (IUCN) has listed the brown stingaree under Least Concern, as there is negligible fishing pressure across most of its range.

References

  1. 1 2 3 4 5 Kyne, P.M.; White, W.T. (2019). "Urolophus lobatus". IUCN Red List of Threatened Species . 2019: e.T60097A68649676. doi: 10.2305/IUCN.UK.2019-1.RLTS.T60097A68649676.en . Retrieved 15 November 2021.
  2. ↑ McKay, R.J. (1966). "Studies on Western Australian sharks and rays of the families Scyliorhinidae, Urolophidae and Torpedinidae". Journal of the Royal Society of Western Australia. 49 (3): 65–82.
  3. 1 2 3 Platell, M.E.; I.C. Potter & K.R. Clarke (1998). "Resource partitioning by four species of elasmobranchs (Batoidea: Urolophidae) in coastal waters of temperate Australia". Marine Biology. 131 (4): 719–734. Bibcode:1998MarBi.131..719P. doi:10.1007/s002270050363.
  4. 1 2 3 4 Last, P.R. & J.D. Stevens (2009). Sharks and Rays of Australia (second ed.). Harvard University Press. p. 419–420. ISBN   978-0-674-03411-2.
  5. ↑ Last, P.R. & L.J.V. Compagno (1999). "Myliobatiformes: Urolophidae". In Carpenter, K.E. & V.H. Niem (eds.). FAO identification guide for fishery purposes: The living marine resources of the Western Central Pacific. Food and Agricultural Organization of the United Nations. pp. 1469–1476. ISBN   92-5-104302-7.
  6. ↑ Platell, M.E. & I.C. Potter (15 June 2001). "Partitioning of food resources amongst 18 abundant benthic carnivorous fish species in marine waters on the lower west coast of Australia". Journal of Experimental Marine Biology and Ecology. 261 (1): 31–54. doi:10.1016/s0022-0981(01)00257-x. PMID   11438104.
  7. ↑ Campbell, R.R. & I. Beveridge (2002). "The genus Acanthobothrium (Cestoda : Tetraphyllidea : Onchobothriidae) parasitic in Australian elasmobranch fishes". Invertebrate Systematics. 16 (2): 237–344. doi:10.1071/IT01004.
  8. ↑ White, W.T.; M.E. Platell & I.C. Potter (2001). "Relationship between reproductive biology and age composition and growth in Urolophus lobatus (Batoidea: Urolophidae)". Marine Biology. 138 (1): 135–147. Bibcode:2001MarBi.138..135W. doi:10.1007/s002270000436.
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