Tropical sawshark

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Tropical sawshark
Pristiophorus delicatus csiro-nfc.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Pristiophoriformes
Family: Pristiophoridae
Genus: Pristiophorus
Species:
P. delicatus
Binomial name
Pristiophorus delicatus
Tropical Sawshark Range.png
Range of the Tropical sawshark
Synonyms

Pristiophorus peroniensisYearsley, Last & White, 2008 [2]

The tropical sawshark, Pristiophorus delicatus, is a recently described species of sawshark, family Pristiophoridae, formerly known in literature as Pristiophorus sp. B. It is endemic to northeastern Australia, found on the upper continental slope off Queensland from south of the Samaurez Reef, at a depth of 246–405 meters (807–1,329 ft). Its specific epithet delicatus is Latin for "delicate", referring to the fine teeth on its saw-like rostrum. [3]

This is a small species; the maximum known length is 85 cm (33 in) for females and 63 cm (25 in) for males (although no mature males have yet been examined). The body is slender with a circular cross-section, and depressed forward of the gill slits. The elongated, saw-like snout tapers evenly to its tip, and bears very slender lateral teeth of variable length and a pair of filamentous, dorsoventrally flattened barbels. The eyes are large and oval in shape. Its nostrils about one-third the distance from the corner of the mouth to the barbel attachment on the rostrum. [4] The mouth is large and broadly arched; there are 47 tooth rows in the upper jaw and 37 in the lower. The teeth have flattened, oval bases and a single narrow, pointed cusp. The pectoral fins are large with narrowed rounded tips and weakly concave rear margins. The two dorsal fins are well-separated, the first longer and broader than the second. The caudal fin is short, with the lower lobe absent. [3]

The coloration is medium brown above and white below; there are pronounced white rear margins on the dorsal and caudal fins. The paired fins are mostly pale with brownish basal portions clearly demarcated from the rest of the fin. [3] Very little is known of the biology of the tropical sawshark; its small size may indicate that it is reproductively productive. There is little fishing pressure within its range, and so it is classified as of Least Concern by the World Conservation Union. [1]

Related Research Articles

Sawshark Family of fishes

A sawshark or saw shark is a member of a shark order bearing a unique long, saw-like rostrum edged with sharp teeth, which they use to slash and disable their prey. There are eight species within the Pristiophoriformes, including the longnose or common sawshark, shortnose sawshark, Japanese sawshark, Bahamas sawshark, sixgill sawshark, African dwarf sawshark, Lana's sawshark and the tropical sawshark.

Rajiformes order of fishes in the superorder Batoidea

Rajiformes is one of the four orders in the superorder Batoidea, flattened cartilaginous fishes related to sharks. Rajiforms are distinguished by the presence of greatly enlarged pectoral fins, which reach as far forward as the sides of the head, with a generally flattened body. The undulatory pectoral fin motion diagnostic to this taxon is known as rajiform locomotion. The eyes and spiracles are located on the upper surface of the head and the gill slits are on the underside of the body. Most species give birth to live young, although some lay eggs enclosed in a horny capsule.

Bahamas sawshark Species of shark

The Bahamas sawshark, Pristiophorus schroederi, is a sawshark of the family Pristiophoridae, found in the western Central Atlantic Ocean from the Bahamas and Cuba at depths of between 400 and 1,000 m. These sharks are at least 80 cm long.

<i>Cephaloscyllium</i> Genus of sharks

Cephaloscyllium is a genus of catsharks, and part of the family Scyliorhinidae, commonly known as swellsharks because of their ability to inflate their bodies with water or air as a defense against predators. These sluggish, bottom-dwelling sharks are found widely in the tropical and temperate coastal waters of the Indian and Pacific Oceans. They have stocky, spindle-shaped bodies and short, broad, and flattened heads. The mouth is capacious, containing many small teeth and lacking furrows at the corners. The two dorsal fins are placed far back on the body, with the first much larger than the second. Different species have various color patterns of saddles, blotches, reticulations, and/or spots. The largest members of the genus can grow over 1 m (3.3 ft) in length. Swellsharks prey on a variety of fishes and invertebrates, and are oviparous, with females producing egg capsules in pairs. They are harmless and have been deemed of having no commercial value.

Speartooth shark Species of shark

The speartooth shark is an extremely rare species of river shark, belonging to the family Carcharhinidae. It inhabits coastal marine waters and tidal reaches of large tropical rivers in northern Australia and New Guinea. Despite being a member of the river shark genus, it is also found in near-shore marine waters, favoring highly turbid environments over a wide range of salinities. This robustly built, gray-colored shark is characterized by a short and broad snout, tiny eyes, a relatively large second dorsal fin, and a black blotch beneath each pectoral fin near the tip. Another identifying trait is its teeth, which are large, triangular, and serrated in the upper jaw and narrow, spear-like, and serrated only near the tips in the lower jaw. Adults grow to about 2.6 m (8.5 ft) long.

Graceful shark Species of shark

The graceful shark or Queensland shark is a species of requiem shark, in the family Carcharhinidae, found in the tropical Indo-Pacific, from the Gulf of Aden to northern Australia. It is a midwater species that has been recorded to a depth of 50 m (160 ft). A stoutly built shark growing up to 1.7 m (5.6 ft) long, the graceful shark has a short, wedge-shaped snout, large, sickle-shaped pectoral fins and first dorsal fin, and black tips on most fins.

Hardnose shark Species of shark

The hardnose shark is a species of requiem shark, in the family Carcharhinidae, so named because of the heavily calcified cartilages in its snout. A small bronze-coloured shark reaching a length of 1.1 m (3.6 ft), it has a slender body and a long, pointed snout. Its two modestly sized dorsal fins have distinctively elongated rear tips. The hardnose shark is widely distributed in the western Indo-Pacific, from Kenya to southern China and northern Australia. It inhabits warm, shallow waters close to shore.

Longnose sawshark Species of shark

The longnose sawshark or common sawshark, is a sawshark of the family Pristiophoridae.

Bluegrey carpetshark Species of shark

The bluegrey carpetshark or Colclough's shark, is an uncommon species of carpet shark endemic to shallow inshore waters off northeastern Australia. It is one of the two extant members of the family Brachaeluridae. The bluegrey carpetshark has a stocky body with a wide, slightly flattened head, dorsally placed eyes, and a pair of long barbels with posterior skin flaps. It has large pectoral fins, two dorsal fins of unequal size placed far back on the body, and a sizable space between the anal fin and the base of the caudal fin. Growing to 76 cm (30 in) long, this species has a black-and-white color pattern as a juvenile, which largely fades with age such as that adults are brownish.

Australian sawtail catshark Species of shark

The Australian sawtail catshark is a common species of catshark, and part of the family Scyliorhinidae, endemic to southern Australian waters. It is found on or near the bottom of the outer continental shelf and upper continental slope, at depths of 85 to 823 m. This slim-bodied species is characterized by crests of enlarged dermal denticles along both the dorsal and ventral edges of its caudal fin and caudal peduncle, along with a color pattern of broad, dark saddles outlined in white. It can grow to 61 cm (24 in) in length. The Australian sawtail catshark feeds mainly on fishes, crustaceans, and cephalopods. Females are oviparous and lay eggs enclosed by capsules. This species is often caught incidentally by commercial bottom trawl fisheries, but is not significantly threatened by fishing activity. Thus, it has been assessed as of Least Concern by the International Union for Conservation of Nature (IUCN).

Slender sawtail catshark Species of shark

The slender sawtail catshark is a little-known species of catshark, part of the family Scyliorhinidae, endemic to northern Australia. It is found over the continental slope in 290–470 m (950–1,540 ft) on water. Growing to 34 cm (13 in) long, this shark has a slim gray body with four dark saddle markings below the dorsal fins and on the caudal fin, as well as a prominent crest of enlarged dermal denticles along the dorsal edge of the caudal fin. The slender sawtail catshark is not valued by fisheries but is taken as bycatch. The International Union for Conservation of Nature (IUCN) presently lacks enough information to assess its conservation status.

Northern river shark Species of shark

The northern river shark or New Guinea river shark is a species of requiem shark, in the family Carcharhinidae, found in scattered tidal rivers and associated coastal waters in northern Australia and in Papua New Guinea. This species inhabits areas with poor visibility, soft bottoms, and large tides, with immature sharks ranging into fresh and brackish water. It is similar to other river sharks in having a stocky grey body with a high back, tiny eyes, and broad fins. It measures up to 2.5 m (8.2 ft) long.

Northern sawtail catshark Species of shark

The northern sawtail catshark is a little-known species of catshark, and part of the family Scyliorhinidae, endemic to northeastern Australia. It is demersal in nature and inhabits the upper continental slope at a depth of 300–420 m (980–1,380 ft). A small, slender species growing no longer than 42 cm (17 in), the northern sawtail catshark is characterized by a series of dark, narrow saddles along its back and tail, and rows of prominently enlarged dermal denticles along the upper edge of its caudal fin and the underside of its caudal peduncle. The International Union for Conservation of Nature (IUCN) does not yet have enough information to assess its conservation status.

The saddled swellshark is a rare species of catshark, and part of the family Scyliorhinidae, endemic to Eastern Australia. This bottom-dwelling species is found on the outer continental shelf and upper continental slope at a depth of 115–605 m (377–1,985 ft). It is a robustly built shark with a short, broad, flattened head and a capacious mouth. Adults are patterned with saddles on a brownish or grayish background, which varies between tropical and temperate sharks; juveniles are light-colored with many spots. This shark reaches 74 cm (29 in) in length. Like other swellsharks, it can inflate itself as a defensive measure. Reproduction is oviparous.

The narrowbar swellshark is a rare species of catshark, and part of the family Scyliorhinidae, known only from two specimens collected near Flinders Reef off northeastern Australia. This species reaches at least 44.5 cm (17.5 in) in length, and has a stocky body with a short, broad head. It can be readily identified by its zebra-like dorsal color pattern of transverse brown bars on a yellowish background. Like other swellsharks, it can inflate its body as a defensive measure.

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.

The flagtail swellshark is a little-known species of catshark, belonging to the family Scyliorhinidae, found at a depth of 480–700 m (1,570–2,300 ft) off northeastern Queensland, and possibly also nearby islands. This stout-bodied shark has a short, broad, and flattened head with a capacious mouth. Adults have a variegated brown coloration with 9–10 darker dorsal saddles and "V"-shaped blotch at the tip of the upper caudal fin lobe. Juveniles are yellow with narrow brown bars instead of saddles, and a distinctive marking between the spiracles shaped like two loops connected by a line. Like other swellsharks, this species can inflate its body when threatened.

Figaro is a genus of catshark, and part of the family Scyliorhinidae. Until 2008, Figaro was generally considered to be a subgenus of Galeus. The two known species are found off Australia, inhabiting deep, offshore waters on or near the bottom. Figaro contains small, slender, firm-bodied sharks that bear distinctive crests of enlarged, spiny dermal denticles along the dorsal and ventral edges of their short caudal fins. The caudal peduncle is relatively long, such as that the anal and caudal fins are some distance apart. In adult males, the inner margins of the pelvic fins are fused together to form a subtle "apron" over the claspers. F. boardmani is a predator of fishes, crustaceans, and cephalopods, and is oviparous; less is known about the F. striatus. Both are harmless and are of no economic importance.

Indonesian angelshark Species of shark

The Indonesian angelshark is a rare species of angelshark, family Squatinidae, known only from a few specimens collected from fish landing sites in southern Indonesia. It is thought to inhabit the deep waters of the continental slope. Reaching at least 1.34 m (4.4 ft) long, this species has a flattened, ray-like shape and a well-developed tail and caudal fin. It is characterized by the absences of fringes on its nasal barbels and thorns down the midline of its back, as well as by its relatively plain grayish-brown dorsal coloration with dark saddles beneath the dorsal fin bases and a black leading margin on the underside of the pectoral fins. The International Union for Conservation of Nature (IUCN) has classified it as Critically Endangered due to significant fishing pressure.

The Philippines angelshark is a species of angelshark, family Squatinidae, known only from a 33 cm (13 in) long immature female caught in the Philippines, where it is the only known representative of its family. It has a flattened body and head with greatly expanded pectoral and pelvic fins, and is greenish above with brown spots. Identifying traits of this species include the spiracles, which are more widely spaced than the eyes and bear papillae on the posterior inner rims, and the relative positions of the two dorsal fins. Additionally, S. caillieti lacks fringes on its barbels, enlarged thorns along the middle of its back, and ocelli ("eyespots") on its fins.

References

  1. 1 2 Cavanagh, R.D.; Kyne, P.M.; Fowler, S.L.; Musick, J.A. & Bennett, M.B. (2003). The Conservation Status of Australasian Chondrichthyans. Brisbane: The University of Queensland, School of Biomedical Sciences. ISBN   0-9751041-1-X.
  2. Pristiophorus delicatus, Encyclopedia of Life, http://www.eol.org/pages/7199561
  3. 1 2 3 Yearsley, G.K.; Last, P.R. & White, W.T. (26 June 2008). "A new species of sawshark, Pristiophorus delicatus sp. nov (Pristiophoriformes: Pristiophoridae), from northeastern Australia". In Last, P.R.; White, W.T. & Pogonoski, J.J. (eds.). Descriptions of New Australian Chondrichthyans. Hobart: CSIRO Marine and Atmospheric Research. pp. 23–34.
  4. Dianne J. Bray, 2011, Pristiophorus delicatus, in Fishes of Australia, Retrieved 16 Oct 2014, http://www.fishesofaustralia.net.au/home/species/2611