Urolophidae

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Urolophidae
Urolophus cruciatus.jpg
Crossback stingaree
(Urolophus cruciatus)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Batoidea
Order: Myliobatiformes
Suborder: Myliobatoidei
Superfamily: Urolophoidea
Family: Urolophidae
J. P. Müller & Henle, 1841
Genera

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 (5.9 and 31.5 in) 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.

Contents

Stingarees feed on or near the sea floor, consuming small invertebrates and occasionally bony fishes. They are aplacental viviparous, meaning their embryos emerge from eggs inside the uterus, and are sustained to term first by yolk and later by maternally produced histotroph ("uterine milk"). As far is known, the gestation period lasts around a year and litter sizes tend to be small. Stingarees have one or two relatively large, venomous stinging spines on their tail for defense, with which they can inflict a painful wound on humans. Generally, stingarees have no economic value. Some species form a substantial component of the bycatch of commercial trawl fisheries.

Taxonomy and phylogeny

The Kapala stingaree (U. kapalensis), one of several newly described urolophids Kapala stingaree.jpg
The Kapala stingaree (U. kapalensis), one of several newly described urolophids

The German biologists Johannes Müller and Jakob Henle created the genus Urolophus in 1837; [1] in their subsequent 1838–41 Systematische Beschreibung der Plagiostomen, the pair created the genus Trygonoptera and also made the first reference to the urolophids as a group. [2] The family has traditionally also included the genera Urobatis and Urotrygon of the Americas; John McEachran, Katherine Dunn, and Tsutomu Miyake moved them to their own family, Urotrygonidae, in 1996. [3]

Recent phylogenetic analyses have confirmed the urolophids and related taxa belong to the order Myliobatiformes; they were once placed in the order Rajiformes with the guitarfishes and skates. [4] Based on morphological characters, John McEachran and Neil Aschliman determined in a 2004 study that the urolophids formed a clade with the giant stingaree (Plesiobatis daviesi), and that the two were basal to a clade containing all other myliobatiform families except Platyrhinidae, Hexatrygonidae, and Zanobatidae. They proposed including Plesiobatis in the family Urolophidae, and classifying the family within the superfamily Urolophoidea within Myliobatiformes. [5]

Distribution and habitat

The striped stingaree (T. ovalis) prefers rocky or seagrass habitats. Stingaree in seagrass.jpg
The striped stingaree (T. ovalis) prefers rocky or seagrass habitats.

The center of biodiversity for stingarees is Australia, where all 6 Trygonoptera and 15 of the 22 Urolophus species are endemic. [6] [7] A number of species are also found in the Coral Sea, a few in the Malay Archipelago, and one (the sepia stingray, U. aurantiacus) in the northwestern Pacific. [6] [8] Stingarees are bottom-dwelling rays that can be found from very shallow, inshore habitats such as estuaries and bays, to a depth of 420 m (1,380 ft) well offshore on the upper continental shelf. [8] Some are extremely common; one study in the coastal waters of southwestern Australia found that the four most abundant stingaree species constituted over 17% of the biomass of benthic fishes. [9]

Description

The eastern shovelnose stingaree (T. imitata), which has a rounded disc and no dorsal fin or lateral skin folds on its tail. Stingaree sydney.jpg
The eastern shovelnose stingaree (T. imitata), which has a rounded disc and no dorsal fin or lateral skin folds on its tail.

Stingarees are modestly sized, ranging from 30 to 80 cm (12 to 31 in) long. They have greatly enlarged pectoral fins fused to the head, forming a disc that may be nearly circular, to oval, to rhomboid in shape. The snout is usually short and does not protrude much from the disc. The eyes are placed atop the disc and usually fairly large; immediately posterior are teardrop-shaped spiracles (auxiliary respiratory openings). There is a curtain of skin between the nostrils, formed from the fusion of the anterior nasal flaps, that reaches the mouth. There are varying numbers of papillae (nipple-like structures) on the floor of the mouth and sometimes also on the outside of the lower jaw. The teeth in both jaws are small, with rhomboid bases and blunt to pointed crowns; they are arranged with a quincunx pattern and number less than 50 rows in either jaw. The five pairs of gill slits are short and located beneath the disc. [7] [8]

The pelvic fins are small with rounded margins; claspers are found on males. The tail is shorter than to about equal to the disc, either flattened or thickly oval in cross-section, and ends in a leaf-shaped, symmetrical caudal fin. One or two relatively large, serrated stinging spines are placed atop the tail about halfway along its length. Some species have a small dorsal fin immediately before the spine, and/or lateral skin folds running along either side of the tail. [7] [8] All species lack dermal denticles (except for the New Ireland stingaree, U. armatus). [10] Stingarees are generally shades of yellow, green, brown or gray above and pale below; some species are plain, while others are adorned with spots, rings, blotches, lines, or more complex patterns. [8]

Biology and ecology

One of the most common stingarees off southern Australia, the sparsely-spotted stingaree (U. paucimaculatus) feeds mainly on crustaceans. Melbourne stingaree.jpg
One of the most common stingarees off southern Australia, the sparsely-spotted stingaree (U. paucimaculatus) feeds mainly on crustaceans.

Stingarees are slow swimmers that can often be found lying still on the bottom, sometimes partly or completely buried in sediment. They are predators of small benthic and burrowing invertebrates such as crustaceans and polychaete worms, and also occasionally small bony fishes. [8] Studies have shown that stingarees that overlap in range differ in their diet composition, which likely serves to reduce competition. For example, off southwestern Australia the masked stingaree (T. personata) and western shovelnose stingaree (T. mucosa) feed mostly on different types of polychaetes, while the sparsely-spotted stingaree (U. paucimaculatus) and lobed stingaree (U. lobatus) feed mostly on different types of crustaceans. [9]

Like other myliobatiforms, stingarees have a viviparous mode of reproduction in which the embryos hatch within the uterus and are nourished first by yolk, and later by histotroph ("uterine milk") produced by the mother and likely delivered through specialized extensions of the uterine epithelium called "trophonemata". For those species whose life histories have been investigated, the gestation period lasts 10–12 months and the litter size is small, no more than one or two in some cases. [7] [8] The small litter is likely due to the relatively large size of stingaree pups, which measure around half the maximum size at birth. [11]

Human interactions

Though generally innocuous towards humans, when disturbed stingarees can inflict a painful wound with their stout, venomous stings. Species differ in temperament; the sparse-spotted stingaree (U. paucimaculatus) is reportedly more aggressive, and the spotted stingaree (U. gigas) less so. When threatened, the crossback stingaree (U. cruciatus) raises its tail over its disc like a scorpion. [12] Some species of stingarees are regularly caught incidentally in bottom trawls by commercial fisheries. They are generally discarded due to their small size, though some may be processed into fishmeal. [7] [8] Stingarees caught from shallow water likely have relatively high chances of survival, but of concern is their tendency to abort any gestating young when captured and handled. [13] [14]

Related Research Articles

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

The deepwater stingray or giant stingaree is a species of stingray and the sole member of the family Plesiobatidae. It is widely distributed in the Indo-Pacific, typically over fine sediments on the upper continental slope at depths of 275–680 m (900–2,230 ft). This species reaches 2.7 m (8.9 ft) in length and 1.5 m (4.9 ft) in width. It has an oval pectoral fin disc with a long, flexible, broad-angled snout. Most of the entire latter half of its tail supports a distinctively long, slender, leaf-shaped caudal fin. Its coloration is dark above and white below, and its skin is almost completely covered by tiny dermal denticles.

<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.

<i>Trygonoptera</i> Genus of cartilaginous fishes

Trygonoptera is a genus of round rays endemic to the waters around Australia. Müller and Henle defined Trygonoptera in 1841. It has often been considered synonymous with Urolophus, but this has been refuted by recent studies. Trygonoptera can be distinguished from Urolophus in that the outer rims of its nostrils are enlarged into broad, flattened lobes; the two also differ in aspects of the skeleton.

<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">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.

<i>Urolophus</i> Genus of cartilaginous fishes

Urolophus is a genus of round rays mostly native to the western Pacific Ocean and the Indian Ocean, though one species occurs in the Pacific waters of the Mexican coast. Müller and Henle erected Urolophus in an 1837 issue of Bericht Akademie der Wissenschaften zu Berlin. The name is derived from the Greek oura, meaning "tail", and lophos, meaning "crest". In Urolophus, the outer rims of the nostrils are not enlarged into lobes, but may form a small knob at the back.

<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 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 color pattern resembles a mosaic of dark brown rings with light-colored 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 Java stingaree was a species of stingray in the family Urolophidae, known only from a single female specimen 33 cm (13 in) long caught off Jakarta, Indonesia. This species is characterized by an oval-shaped pectoral fin disc longer than wide, and a tail with a dorsal fin in front of the stinging spine and a caudal fin. It is brown above, with darker and lighter spots. The International Union for Conservation of Nature has listed the Java stingaree as Extinct; it has not been recorded since its discovery over 150 years ago, and its range is subject to heavy fishing pressure and habitat degradation.

The lobed stingaree 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 color 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).

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.

<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. ↑ Müller, J. & F.G.J. Henle (1837). "Gattungen der Haifische und Rochen nach einer von ihm mit Hrn. Henle unternommenen gemeinschaftlichen Arbeit über die Naturgeschichte der Knorpelfische". Bericht Akademie der Wissenschaften zu Berlin. 1837: 111–118.
  2. ↑ Müller, J. & F.G.J. Henle (1838–1841). Systematische Beschreibung der Plagiostomen. Veit und Comp. p. 173–174.
  3. ↑ McEachran, J.D.; K.A. Dunn & T. Miyake (1996). "Interrelationships of the batoid fishes (Chondrichthyes: Batoidea)". In Stiassny, M.L.J.; L.R. Parenti & G.D. Johnson (eds.). Interrelationships of Fishes. Academic Press. pp. 63–84. ISBN   978-0-12-670950-6.
  4. ↑ Nelson, J.S. (2006). Fishes of the World (fourth ed.). John Wiley. pp. 69–82. ISBN   0-471-25031-7.
  5. ↑ McEachran, J.D. & N. Aschliman (2004). "Phylogeny of Batoidea". In Carrier, J.C.; J.A. Musick & M.R. Heithaus (eds.). Biology of Sharks and Their Relatives. CRC Press. pp. 79–114.
  6. 1 2 Séret, B. & P.R. Last (2003). "Description of four new stingarees of the genus Urolophus (Batoidea: Urolophidae) from the Coral Sea, south-west Pacific". Cybium. 27 (4): 307–320.
  7. 1 2 3 4 5 Last, P.R. & J.D. Stevens (2009). Sharks and Rays of Australia (second ed.). Harvard University Press. p. 398–428. ISBN   0-674-03411-2.
  8. 1 2 3 4 5 6 7 8 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.
  9. 1 2 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: 719–734. doi:10.1007/s002270050363.
  10. ↑ Fowler, H.W. (1941). "Contributions to the biology of the Philippine Archipelago and adjacent regions". Bulletin of the United States National Museum. 100 (13): 1–879.
  11. ↑ White, W.T. & I.C. Potter (2005). "Reproductive biology, size and age compositions and growth of the batoid Urolophus paucimaculatus, including comparisons with other species of the Urolophidae". Marine and Freshwater Research. 56 (1): 101–110. doi:10.1071/mf04225.
  12. ↑ Michael, S.W. (1993). Reef Sharks & Rays of the World. Sea Challengers. p. 91. ISBN   0-930118-18-9.
  13. ↑ Kyne, P.M. & Last, P.R. (2006). "Trygonoptera testacea". IUCN Red List of Threatened Species . 2006: e.T60085A12236256. doi: 10.2305/IUCN.UK.2006.RLTS.T60085A12236256.en .
  14. ↑ Trinnie, F.I.; White, W.T. & Walker, T.I. (2006). "Urolophus paucimaculatus". IUCN Red List of Threatened Species . 2006: e.T60102A12300571. doi: 10.2305/IUCN.UK.2006.RLTS.T60102A12300571.en .
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