Lollipop catshark

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Lollipop catshark
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Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Subdivision: Selachimorpha
Order: Carcharhiniformes
Family: Scyliorhinidae
Genus: Cephalurus
Bigelow & Schroeder, 1941
Species:
C. cephalus
Binomial name
Cephalurus cephalus
Cephalurus cephalus distmap.png
Synonyms

Catulus cephalusGilbert, 1892

The lollipop catshark (Cephalurus cephalus) is a little-known species of deep sea catshark, belonging to the family Scyliorhinidae, and the only described member of its genus. [2] 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.

Contents

Taxonomy and phylogeny

The lollipop catshark was originally described by American ichthyologist Charles Henry Gilbert as Catulus cephalus, in the 1892 14th volume of Proceedings of the United States National Museum. His description was based on a 24 cm (9.4 in) long adult male caught from a depth of 841 m (2,759 ft) off Clarion Island in the Revillagigedo Islands. [3] In 1941, Henry F. Bigelow and William C. Schroeder created the new genus Cephalurus for this species. [4] One or more yet-undescribed species of Cephalurus appear to exist off Panama, Peru, and Chile, which differ slightly from C. cephalus in appearance and size. [3]

Based on morphological and molecular phylogenetic evidence, Cephalurus is thought to form a clade with the genera Asymbolus , Parmaturus , Galeus , and Apristurus . However, different authors disagree on the interrelationships within this group; molecular data supports Cephalurus and Parmaturus as sister groups. [5]

Distribution and habitat

The range of the lollipop catshark extends from the Gulf of California to off the southern Baja peninsula. This benthic species occurs around the outer continental shelf and upper continental slope at depths of 155–937 m (509–3,074 ft), where it is reportedly abundant. [3]

Description

The lollipop catshark is so named because of its peculiar tadpole-like shape, with an enormously expanded head and branchial region (containing the gills) coupled with a slender, cylindrical body tapering towards the tail. [3] The head is wide, flattened, and rounded, comprising a third of the total length in adults. The snout is very short and blunt, with widely spaced nostrils flanked by moderately developed flaps of skin. The mouth has a pair of furrows at the corners that curl around from the upper to the lower jaw. The widely spaced teeth have a large central cusp flanked by 13 cusplets on both sides; the upper teeth are straight while the lower teeth are curved somewhat outward. There are numerous small papillae on the tongue and roof of the mouth, and a light-colored membrane lining the inside of the mouth. The large eyes are oval in shape and followed by prominent spiracles. The five pairs of gill slits are distinctive, being strongly arched forward. [4] [6]

The body is very soft, almost gelatinous. [3] Unlike in other catsharks, the first dorsal fin originates well in front of the pelvic fins. The second dorsal fin is about as long and slightly lower than the first, and is positioned opposite the anal fin. The dorsal, pelvic, and anal fins have convex leading and nearly straight trailing margins. The pectoral fins are angular, twice as long as wide, and originate beneath the fourth gill slit. The caudal fin is low, with an indistinct lower lobe and a shallow ventral notch near the tip of the upper lobe. [4] [6] The skin is delicate and sparsely covered by thorn-like dermal denticles interspersed with narrower hair-like denticles that become more numerous on the back. [4] The coloration is a plain brownish gray all over, sometimes lightening to almost white at the dorsal, pectoral, and pelvic fin margins. The eyes are an iridescent green. [6] Adults typically attain a length of 24 cm (9.4 in), but may grow up to 28 cm (11 in) long. [3]

Biology and ecology

The enlarged gill region and expanded gill filaments of the lollipop catshark suggest that it is adapted for living in deep-sea basins with very low levels of dissolved oxygen and perhaps also high temperatures and salinity. [7] This shark feeds mainly on crustaceans, followed by fishes. [8] The lollipop catshark is aplacental viviparous, with birthing apparently taking place in early summer. Females have two functional ovaries and retain pairs of thin-shelled egg cases (one within each oviduct) within their bodies until they hatch. [9] Newborns measure about 10 cm (3.9 in) long; sexual maturation is reached at a length of 19 cm (7.5 in) for males and 24 cm (9.4 in) for females. [1]

Human interactions

The lollipop catshark is of no significance to fisheries. [3] It may be taken as bycatch; though the depths at which it occupies may offer some protection from fishing pressure. The International Union for Conservation of Nature (IUCN) presently assesses it as least concern. [1]

Related Research Articles

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The pygmy ribbontail catshark is a species of finback catshark, family Proscylliidae, distributed patchily in the western Indo-Pacific from Tanzania to the Philippines. It occurs around the edges of continental and insular shelves at a depth of 71–766 m (233–2,513 ft), typically on or near mud bottoms. One of the smallest living shark species, the pygmy ribbontail catshark grows to a maximum known length of 24 cm (9.4 in). It has a slender body with a low, ribbon-like tail fin, and is dark brown in color with blackish dorsal fin markings and tail bands. This shark feeds mainly on bony fishes, followed by crustaceans and then squid. It is aplacental viviparous with females bearing litters of 1–2 relatively large pups. It is of minimal significance to fisheries, being caught as bycatch in some areas.

<i>Galeus</i> Genus of sharks

Galeus is a genus of catshark, belonging to the family Scyliorhinidae, 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">Quagga catshark</span> Species of fish

The quagga catshark is a species of catshark, belonging to the family Scyliorhinidae. 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">Cloudy catshark</span> Species of shark

The cloudy catshark is a common species of catshark, belonging to the family Scyliorhinidae. It is a bottom-dweller that inhabits rocky reefs in the northwestern Pacific Ocean, from the shore to a depth of 320 m (1,050 ft). Growing up to 50 cm (20 in) long, this small, slim shark has a narrow head with a short blunt snout, no grooves between the nostrils and mouth, and furrows on the lower but not the upper jaw. It is also characterized by extremely rough skin and coloration consisting of a series of dark brown saddles along its back and tail, along with various darker and lighter spots in larger individuals.

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

The Antilles catshark is a common but little-known species of catshark, part of the family Scyliorhinidae. 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">Roughtail catshark</span> Species of shark

The roughtail catshark or marbled catshark is a common species of catshark, part of the family Scyliorhinidae. It is found at a depth of 36–702 m (118–2,303 ft) in the northwestern Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea, from North Carolina to Costa Rica. Individuals of different sexes and ages are segregated to some degree. A small species not exceeding 33 cm (13 in) in length, the roughtail catshark has a slender body with a marbled color pattern of dark saddles and spots, and a prominent crest of enlarged dermal denticles along the dorsal edge of its caudal fin. This species feeds mainly on shrimp and is oviparous. It is caught incidentally in shrimp trawls, though trawl fisheries within its range mostly do not operate at the depths it inhabits. As a result, the International Union for Conservation of Nature has listed it under Least Concern.

<span class="mw-page-title-main">Australian sawtail catshark</span> 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).

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

The longfin sawtail catshark is a rare, little-known species of catshark, part of the family Scyliorhinidae. Once thought to be a subspecies of the roughtail catshark along with the Antilles catshark, it inhabits deep water off the Caribbean coasts of Panama and Colombia. This slim-bodied species has a marbled dorsal color pattern and a prominent crest of enlarged dermal denticles along the dorsal edge of its caudal fin. It can be distinguished from similar species by its relatively longer anal fin and small adult length of under 35 cm (14 in). The longfin sawtail catshark is oviparous.

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

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

The broadfin sawtail catshark is a common species of catshark, part of the family Scyliorhinidae. It is found on or near the bottom at depths of 150–540 m (490–1,770 ft), from southeastern Japan to the East China Sea. A slender species growing to 68 cm (27 in) long, this shark is characterized by a fairly long, pointed snout, a series of indistinct, dark saddles along its back and tail, and a prominent crest of enlarged dermal denticles along the dorsal edge of its caudal fin. In addition, adult males have very long claspers that reach past the anal fin. The broadfin sawtail catshark is an opportunistic predator of bony fishes, cephalopods, and crustaceans, with immature and mature sharks being primarily piscivorous. It is oviparous and reproduces year-round.

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

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

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

The blacktip sawtail catshark is a species of catshark, and part of the family Scyliorhinidae, 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 little-known species of catshark, belonging to the family Scyliorhinidae, 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 catshark, belonging to the family Scyliorhinidae, 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 catshark, family Scyliorhinidae, with 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">Dwarf lanternshark</span> Species of shark

The dwarf lanternshark is a species of dogfish shark in the family Etmopteridae and is the smallest shark in the world, reaching a maximum known length of 20 cm (8 in). It is known to be present only on the upper continental slopes off Colombia and Venezuela, at a depth of 283–439 m (928–1,440 ft). This species can be identified by its small size at maturity, long flattened head, and pattern of black ventral markings and a mid-dorsal line. Like other members of its genus, it is capable of producing light from a distinctive array of photophores. Reproduction is aplacental viviparous, with females gestating two or three young at a time. The dwarf lanternshark is not significant to commercial fisheries, but could be threatened by mortality from bycatch; the degree of impact from human activities on its population is unknown.

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.

References

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