Haploblepharus

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Haploblepharus
Haploblepharus edwardsii Puffadder shyshark.jpg
Puffadder shyshark (H. edwardsii)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Carcharhiniformes
Family: Pentanchidae
Genus: Haploblepharus
Garman, 1913
Type species
Squalus edwardsii
Schinz 1822

Haploblepharus is a genus of deepwater catsharks, belonging to the family Pentanchidae, containing four species of shysharks. Their common name comes from a distinctive defensive behavior in which the shark curls into a circle and covers its eyes with its tail. The genus is endemic to southern Africa, inhabiting shallow coastal waters. All four species are small, stout-bodied sharks with broad, flattened heads and rounded snouts. They are characterized by very large nostrils with enlarged, triangular flaps of skin that reach the mouth, and deep grooves between the nostrils and the mouth. Shysharks are bottom-dwelling predators of bony fishes and invertebrates. They are oviparous, with the females laying egg capsules. These harmless sharks are of no commercial or recreational interest, though their highly limited distributions in heavily fished South African waters are of potential conservation concern.

Contents

Taxonomy and phylogeny

The genus Haploblepharus was created by American zoologist Samuel Garman in 1913, in the 36th volume of Memoirs of the Museum of Comparative Zoology, at Harvard College, to contain the puffadder shyshark, then known as Squalus edwardsii. [1] The name is derived from the Greek haplóos meaning "single", and blepharos meaning "eyelid". [2]

In 1988, Leonard Compagno placed Haploblepharus with Halaelurus and Holohalaelurus in the tribe Halaelurini of the family Scyliorhinidae, based on morphological characters. This interpretation was corroborated by a 2006 phylogenetic analysis based on three mitochondrial DNA genes. However, that study also found that within this group Haploblepharus is most closely related to the genus Halaelurus, which is inconsistent with the presence of three autapomorphic traits in Haploblepharus that are not shared by either Halaelurus or Holohalaelurus. Within the genus, the puffadder shyshark is the most basal species. [3]

Species

Distribution and habitat

All four shyshark species are endemic to the southern tip of Africa; three of them are found only off South Africa, while the range of the dark shyshark extends to southern Namibia. They are bottom-dwelling in nature and usually found in shallow, coastal waters over sandy or rocky bottoms. [1]

Description

The broad, flattened head of a dark shyshark Haploblepharus pictus newport 2.jpg
The broad, flattened head of a dark shyshark

Different shyshark species are very similar to one another in appearance but can be reliably differentiated using morphological measurements. However, in the field the only way to readily tell them apart is by their different color patterns, and even this may be problematic as individuals of the same species can vary considerably in coloration. [4] All four species are small, seldom exceeding 60 cm (24 in) in length. [5]

A shyshark has a stout, spindle-shaped body and a short head comprising less than one-fifth of the total length. The head is broad and dorsally flattened, with a rounded snout. The large, oval eyes have cat-like slit pupils, a rudimentary nictitating membrane (protective third eyelid), and a prominent ridge running underneath. A distinguishing trait of this genus are the large nostrils partially covered by greatly expanded, triangular flaps of skin that overlap the mouth and cover a pair of deep grooves between the nasal excurrent (outflow) openings and the mouth. The mouth is short and curved, with furrows at the corners extending onto both jaws. The teeth have a central cusp and smaller lateral cusplets. The five pairs of gill slits are located on the upper side of the body. [1]

The two dorsal fins are set far back on the body, the first originating behind the pelvic fin midbases and the second originating behind the anal fin midbase. The pectoral fins are moderately large; the dorsal, pelvic, and anal fins are of similar size. The broad caudal fin comprises a fifth of the total length; the upper lobe has a deep ventral notch near the tip and the lower lobe is virtually absent. The skin is thick and covered by well-calcified, leaf-shaped dermal denticles. The coloration is brown above and white below; the brown shyshark is usually plain while the other species have varying patterns of darker "saddles" and white spots. [1]

Biology and ecology

The egg case of a puffadder shyshark Puffadder shyshark egg case.jpg
The egg case of a puffadder shyshark

Shysharks feed on a variety of small benthic bony fishes and invertebrates. In turn, they are preyed upon by larger fishes and marine mammals. When threatened, these sharks adopt a curious posture in which they curl their bodies into a ring and cover their eyes with their tails, which is the origin of the name "shyshark". [1] This behavior likely serves to make the shark more difficult for a predator to swallow. Shysharks are oviparous with females producing egg capsules (known as "mermaid's purses") two at a time. Reproduction has been investigated in the puffadder and dark shysharks; neither species appears to have a distinct breeding season, and their eggs take around three and a half weeks to hatch. [6]

Human interactions

Due to their small size, shysharks pose no danger to humans and are not sought by either commercial or recreational fishers. They are taken as bycatch and hooked by shore anglers, who regard them (and other catsharks) as minor pests. Although shysharks are not uncommon, their extremely limited distribution within heavily fished waters raises concerns that a local increase in fishing pressure or habitat degradation could affect entire species populations. As a result, the International Union for Conservation of Nature (IUCN) has assessed two shyshark species as Near Threatened. [7]

Related Research Articles

<i>Galeus</i> Genus of sharks

Galeus is a genus of deepwater catshark, belonging to the family Pentanchidae, commonly known as sawtail catsharks in reference to a distinctive saw-toothed crest of enlarged dermal denticles, found along the upper edges of their caudal fins. They are found in the Atlantic, the western and central Pacific, and the Gulf of California, inhabiting deep waters at or close to the sea floor. Members of this genus are rather small, slim sharks with firm bodies and thick, rough skin. Their heads are usually fairly long and pointed, and have large mouths with well-developed furrows at the corners. They have large pectoral and anal fins, and two similar dorsal fins placed well back. Many species are ornately patterned with dark saddles and/or blotches. Sawtail catsharks feed on various invertebrates and fishes, and may be either egg-laying or live-bearing. These harmless sharks are sometimes caught as bycatch but are of minimal commercial value.

<span class="mw-page-title-main">Lollipop catshark</span> Species of shark

The lollipop catshark is a little-known species of shark belonging to the family Pentanchidae, the deepwater catsharks, and the only described member of its genus. A diminutive, bottom-dwelling shark of the outer continental shelf and upper continental slope, this species can be readily identified by its tadpole-like shape with a greatly expanded, rounded head and narrow body. The large head houses expanded gills, which are thought to be an adaptation for hypoxic conditions. This shark preys on crustaceans and fishes. Reproduction is aplacental viviparous, with females retaining egg cases internally two at a time until they hatch. There is no fishery interest in this species.

<span class="mw-page-title-main">Balloon shark</span> Species of shark

The balloon shark is a species of catshark, and part of the family Scyliorhinidae, endemic to the southwestern Indian Ocean off South Africa and Mozambique. Benthic in nature, it is found over sandy and muddy flats at depths of 40–600 m (130–1,970 ft). This thick-bodied species has a broad, flattened head and a short tail; its distinguishing traits include narrow, lobe-like skin flaps in front of the nostrils, and a dorsal color pattern of faint darker saddles on a light grayish background.

<span class="mw-page-title-main">Pyjama shark</span> Species of shark

The pyjama shark or striped catshark is a species of catshark, and part of the family Scyliorhinidae, endemic to the coastal waters of South Africa. This abundant, bottom-dwelling species can be found from the intertidal zone to a depth of around 100 m (330 ft), particularly over rocky reefs and kelp beds. With a series of thick, parallel, dark stripes running along its stout body, the pyjama shark has an unmistakable appearance. It is additionally characterized by a short head and snout with a pair of slender barbels that do not reach the mouth, and two dorsal fins that are placed far back on the body. It can grow up to a length of 1.1 m (3.6 ft) long.

<span class="mw-page-title-main">Leopard catshark</span> Species of shark

The leopard catshark is a species of catshark, and part of the family Scyliorhinidae, endemic to the coastal waters of South Africa. Abundant in inshore waters under 20 m (66 ft) deep, this bottom-dweller favors rocky reefs, kelp beds, and sandy flats. Growing to a length of 84 cm (33 in), the leopard catshark has a stout body with two dorsal fins placed well back, and a short head and tail. It is extremely variable in color and pattern, with individuals ranging from almost white to black and covered by diverse patterns of black spots, blotches, rosettes, and/or lines. The color pattern changes with age and some forms seem to be location-specific, suggesting the presence of multiple distinct, local populations. In the past, some of the more distinct color forms have been described as different species.

<span class="mw-page-title-main">Izak catshark</span> Species of catshark, of the family Scyliorhinidae

The Izak catshark or simply Izak is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. This species is common off the coasts of South Africa and southern Namibia. It typically inhabits the outer continental shelf at depths of 100–300 m (330–980 ft), with the males found deeper than the females and juveniles. The Izak catshark has a short, wide, flattened head and a robust body tapering to a long, slender tail. It can be identified by its ornate color pattern of dark brown spots or reticulations and blotches on a light yellowish background, as well as by the enlarged dermal denticles over its pectoral fins and along its dorsal midline from the snout to the second dorsal fin. This species reaches 69 cm (27 in) in length, with the males larger than females.

<span class="mw-page-title-main">Puffadder shyshark</span> Species of shark

The puffadder shyshark, also known as the Happy Eddie, is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. This species is endemic to the temperate waters off the coast of South Africa. This common shark is found on or near the bottom in sandy or rocky habitats, from the intertidal zone to a depth of 130 m (430 ft). Typically reaching 60 cm (24 in) in length, the puffadder shyshark has a slender, flattened body and head. It is strikingly patterned with a series of dark-edged, bright orange "saddles" and numerous small white spots over its back. The Natal shyshark, formally described in 2006, was once considered to be an alternate form of the puffadder shyshark.

<span class="mw-page-title-main">Brown shyshark</span> Species of shark

The brown shyshark or plain happy is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. It is endemic to the shallow, coastal waters of South Africa from west of Cape Agulhas to KwaZulu-Natal. This benthic species is usually found over sandy or rocky bottoms. Measuring up to 73 cm (29 in) long, the brown shyshark is stoutly built, with a broad, flattened head and rounded snout. Unlike other shysharks, the brown shyshark has a plain brown color, though some individuals have faint "saddle" markings or light or dark spots. When threatened, this shark curls into a circle with its tail over its eyes, which is the origin of the name "shyshark". It feeds on bony fishes and lobsters, and is oviparous with females laying pairs of egg capsules. The International Union for Conservation of Nature (IUCN) has assessed this harmless species as Vulnerable. It is of no commercial or recreational interest, but its limited distribution makes its entire population vulnerable to increases in fishing pressure or habitat degradation.

<span class="mw-page-title-main">Dark shyshark</span> Species of shark

The dark shyshark or pretty happy is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. This species is endemic to the temperate waters off southern Namibia and western South Africa. It is benthic in nature and inhabits shallow, inshore waters and favors rocky reefs and kelp forests. Growing to 60 cm (24 in) long, this small, stocky shark has a wide, flattened head with a rounded snout and a large flap of skin extending from before the nostrils to the mouth. Its dorsal coloration is extremely variable and may feature black-edged orange to blackish saddles and/or white spots on a light brown to nearly black background.

<span class="mw-page-title-main">Quagga catshark</span> Species of fish

The quagga catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. A small, slim-bodied shark reaching 37 cm (15 in) in length, it has a distinctive color pattern of narrow, dark brown vertical bars, which resemble those of the quagga. Its head is short and flattened, with a pointed snout tip that is not upturned.

<span class="mw-page-title-main">Tiger catshark</span> Species of shark

The tiger catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. It is found over sandy areas and near reef peripheries off South Africa and perhaps Mozambique, from close to shore to usually no deeper than 100 m (330 ft). Reaching a length of 50 cm (20 in), this small, slim shark has a broad, flattened head with an upturned snout tip. It can additionally be identified by its dorsal colour pattern of ten dark brown saddles on a yellowish brown background.

<span class="mw-page-title-main">Antilles catshark</span> Species of shark

The Antilles catshark is a common but little-known species of deepwater catshark, belonging of the family Pentanchidae. It is found on or near the bottom at a depth of 293–695 m (961–2,280 ft) off Florida and the West Indies from Jamaica to Martinique. It was once regarded as a subspecies of the similar roughtail catshark, along with the longfin sawtail catshark. Growing to 46 cm (18 in) long, the Antilles catshark is a slender species with a marbled color pattern of dark saddles and blotches, as well as a crest of enlarge dermal denticles along the front part of its dorsal caudal fin margin. It feeds on shrimp and may have schooling habits. Reproduction is oviparous.

<span class="mw-page-title-main">Blackmouth catshark</span> Species of shark

The blackmouth catshark is a species of deepwater catshark, belonging yo the family Pentanchidae, common in the northeastern Atlantic Ocean from Iceland to Senegal, including the Mediterranean Sea. It is typically found over the continental slope at depths of 150–1,400 m (490–4,590 ft), on or near muddy bottoms. The youngest sharks generally inhabit shallower water than the older juveniles and adults. This slim-bodied species is characterized by the black interior of its mouth, a marbled pattern of pale-edged brownish saddles or blotches along its back and tail, and a prominent saw-toothed crest of enlarged dermal denticles along the upper edge of its caudal fin. It reaches lengths of 50–79 cm (20–31 in), with sharks in the Atlantic growing larger than those in the Mediterranean.

<span class="mw-page-title-main">Mouse catshark</span> Species of shark

The mouse catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. It is common in the northeastern Atlantic Ocean from Iceland to Western Sahara. There is much taxonomic confusion regarding this species in Icelandic waters, where it may be confounded with another species of Galeus or Apristurus. Probably not exceeding 49 cm (19 in) long, the mouse catshark has a uniformly brown body and is characterized by large, rounded pelvic fins and crests of enlarged dermal denticles along both the dorsal and ventral caudal fin margins. In addition, in adult males the inner margins of the pelvic fins are merged into an "apron".

<span class="mw-page-title-main">African sawtail catshark</span> Species of shark

The African sawtail catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. Demersal in nature, it is found at depths of 160–720 m (520–2,360 ft) off the western African coast from Morocco to South Africa. This slender species has a rather long, pointed snout, a series of dark saddles along the back and tail, and a prominent crest of enlarged dermal denticles along the upper edge of the caudal fin. Its maximum known length is 46 cm (18 in).

<span class="mw-page-title-main">Blacktip sawtail catshark</span> Species of shark

The blacktip sawtail catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks, This species is found off the coasts of Taiwan and the Philippines. It is demersal in nature and occurs deeper than 60 m (200 ft). Growing up to 46 cm (18 in) long, this slim-bodied species is characterized by its plain brownish dorsal coloration with dark tips on the dorsal and caudal fins, and a prominent crest of enlarged dermal denticles on the upper edge of the caudal fin. It is oviparous, with females producing encapsulated eggs two at a time year-round. The blacktip sawtail catshark is caught incidentally in bottom trawls and used for fishmeal in Taiwan.

<span class="mw-page-title-main">Dwarf sawtail catshark</span> Species of shark

The dwarf sawtail catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. This shark is found exclusively in the deep waters off Luzon in the Philippines. Unlike other members of its genus, this slender, diminutive shark has a short, rounded snout and very short furrows at the corners of its jaws. It has indistinct darker saddles beneath each dorsal fin and two dark bands on the caudal fin, as well as a prominent crest of enlarged dermal denticles along the upper caudal fin margin.

<span class="mw-page-title-main">Springer's sawtail catshark</span> Species of shark

Springer's sawtail catshark is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. This shark is found in waters 457–699 m (1,499–2,293 ft) deep off the islands of the Antilles, from Cuba to the Leewards. A small, slim-bodied species reaching a length of 48 cm (19 in), the Springer's sawtail catshark can be identified by its color pattern of horizontal dark stripes in front of the first dorsal fin, and dark dorsal saddles behind. It is additionally characterized by the presence of saw-toothed crests, made of enlarged dermal denticles along both the dorsal and the ventral edges of the caudal fin. The Springer's sawtail catshark is oviparous.

<span class="mw-page-title-main">Longhead catshark</span> Species of shark

The longhead catshark or smoothbelly catshark is a species of shark, family Pentanchidae, the deepwater catsharks. This shark has a patchy distribution in the Indo-Pacific from Mozambique to southern Japan to northern Australia. It is found in water between 500 and 1,140 m deep. This species grows to 59 cm (23 in) long and is characterized by its extremely long and narrow snout, short abdomen, and long anal and caudal fins. In addition, a large area of the anterior ventral portion of its body lacks dermal denticles. The longhead catshark is oviparous and the only known cartilaginous fish that is normally hermaphroditic, with the majority of individuals having both the functional reproductive organs of one sex and the undeveloped reproductive organs of the opposite sex.

<span class="mw-page-title-main">Natal shyshark</span> Species of shark

The Natal shyshark, eastern shyshark or happy chappie is a species of shark belonging to the family Pentanchidae, the deepwater catsharks. It was once regarded as the "Natal" form of the puffadder shyshark. This shark is endemic to a small area off South Africa from the Western Cape to KwaZulu-Natal. It is found close to the coast, from the surf zone to a depth of 30 m (98 ft), and has benthic habits. Reaching 50 cm (20 in) in length, the Natal shyshark is similar to the puffadder shyshark in appearance but has a stockier body, less flattened head, a compressed caudal peduncle, and a different color pattern. Rare and under threat from habitat degradation and commercial fishing, it has been assessed as Vulnerable by the International Union for Conservation of Nature (IUCN).

References

  1. 1 2 3 4 5 Compagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Rome: Food and Agricultural Organization. p. 332. ISBN   92-5-101384-5.
  2. Bester, C. Biological Profiles: Puffadder Shyshark. Florida Museum of Natural History Ichthyology Department. Retrieved on August 31, 2009.
  3. Human, B.A.; E.P. Owen; L.J.V. Compagno & E.H. Harley (May 2006). "Testing morphologically based phylogenetic theories within the cartilaginous fishes with molecular data, with special reference to the catshark family (Chondrichthyes; Scyliorhinidae) and the interrelationships within them". Molecular Phylogenetics and Evolution. 39 (2): 384–391. doi:10.1016/j.ympev.2005.09.009. PMID   16293425.
  4. Human, B.A. (2007). "Size-corrected shape variation analysis and quantitative species discrimination in a morphologically conservative catshark genus, Haploblepharus Garman, 1913 (Chondrichthyes: Carcharhiniformes: Scyliorhinidae)". African Natural History. 3: 59–73.
  5. Smith, J.L.B.; M.M. Smith & P.C. Heemstra (2003). Smiths' Sea Fishes. Struik. pp. 91–92. ISBN   1-86872-890-0.
  6. Dainty, A.M. (2002). Biology and ecology of four catshark species in the southwestern Cape, South Africa. M.Sc. thesis, University of Cape Town.
  7. Fowler, S.L.; R.D. Cavanagh; M. Camhi; G.H. Burgess; G.M. Cailliet; S.V. Fordham; C.A. Simpfendorfer & J.A. Musick (2005). Sharks, Rays and Chimaeras: The Status of the Chondrichthyan Fishes. International Union for Conservation of Nature and Natural Resources. pp. 265–266. ISBN   2-8317-0700-5.