Mouse catshark

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Mouse catshark
Pristiurus murinus by collett.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Superorder: Selachimorpha
Order: Carcharhiniformes
Family: Scyliorhinidae
Genus: Galeus
Species:
G. murinus
Binomial name
Galeus murinus
(Collett, 1904)
Galeus murinus distmap.png
Range of the mouse catshark
Synonyms

Pristiurus jenseniiSaemundsson, 1922
Pristiurus murinusCollett, 1904

Contents

The mouse catshark (Galeus murinus) is a species of catshark and part of the family Scyliorhinidae. 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".

Demersal in nature, the mouse catshark inhabits continental slopes at a depth of 380–1,300 m (1,250–4,270 ft). It preys mainly on benthic crustaceans, bony fishes, and cephalopods. Reproduction is oviparous, with females producing "furry" egg capsules. Although it is caught incidentally by commercial trawl fisheries, this species does not appear to be threatened by fishing activities and has been listed under Least Concern by the International Union for Conservation of Nature (IUCN).

Taxonomy and phylogeny

Norwegian zoologist Robert Collett originally described the mouse catshark as Pristiurus murinus, in a 1904 issue of the scientific journal Forhandlinger i Videnskabs-selskabet i Christiania; its specific epithet means "relating to a mouse" in Latin. The type specimen is an immature female 22 cm (8.7 in) long, collected 150 km (93 mi) northwest of the Hebrides at a depth of 1,100–1,300 m (3,600–4,300 ft). [2] Later authors have recognized Pristiurus as a junior synonym of Galeus . [3]

Some taxonomic confusion has arisen over Pristiurus jensenii, described from Iceland by Bjarni Sæmundsson in 1922, which has traditionally been considered the same species as G. murinus. Recently reported data for G. murinus have shown inconsistencies between sharks from Iceland and elsewhere, suggesting that P. jensenii may in fact be a valid species very similar to G. murinus. However, an alternate possibility is that some of the data may have been confounded with a species of Apristurus . [1] The placement of G. murinus within Galeus is problematic as it does not much resemble the more typical members of the genus. [3] On the other hand, a 2005 phylogenetic analysis by Samuel Iglésias and colleagues, based on mitochondrial and nuclear DNA, found that G. murinus forms a clade with G. melastomus, apart from the clade of G. eastmani , G. sauteri, and G. gracilis. [4]

Distribution and habitat

Fairly common, the mouse catshark has recently been found to be more widespread in the northeastern Atlantic than previously thought, occurring from western Iceland and the Faroe Islands to the Hebrides, Scotland, and Ireland, to as far south as France and Western Sahara. This species is found on or near the bottom over the continental slope, in water 380–1,300 m (1,250–4,270 ft) deep. [1] [5] It has been reported from a depth of 656–1,731 m (2,152–5,679 ft) off Iceland, but the figure is confounded by taxonomic confusion. [1]

Description

The maximum length of the mouse catshark has been variously reported as 49 cm (19 in) and 85 cm (33 in). The larger figure comes from Iceland and is reflective of the aforementioned taxonomic confusion, as the specimen of P. jensenii described by Bjarni Sæmundsson was 63 cm (25 in) long. [1] This species has a firm body with a rather long, blunt snout. The nostrils are divided by triangular flaps of skin in front. The eyes are horizontally oval and equipped with rudimentary nictitating membranes (protective third eyelids). A thin ridge is present beneath each eye, and a tiny spiracle behind. The large mouth forms a wide arch, and bears well-developed furrows at the corners. The teeth have a narrow central cusp and multiple lateral cusplets on either side. There are five pairs of gill slits. [6]

The first dorsal fin has a rounded tip and is positioned over the aft portion of the pelvic fins. The second dorsal fin is similar in size and shape as the first, and is positioned over the aft portion of the anal fin. The pectoral fins are large and broad. The pelvic fins are distinctive, being large and wide with an evenly rounded margin. In adult males, the inner margins of the pelvic fins are fused together to form an "apron" partially covering the claspers. The anal fin is large and angular; its base measures roughly 12–13% of the total length, much longer than the distance between the dorsal fins. The pelvic, anal, and caudal fins are all very close to each other. The caudal peduncle is cylindrical and the caudal fin is low, with a small lower lobe and a ventral notch near the tip of the upper lobe. The dermal denticles are small and overlapping; each has an arrowhead-shaped crown bearing a horizontal ridge and three marginal teeth. There is a prominent crest of enlarged denticles along the dorsal caudal fin margin. Unusually for the genus, there is also a similar denticle crest along the underside of the caudal peduncle, extending to the forward portion of the ventral caudal fin margin. This shark is plain brown, lightening slightly on the underside; the interior of the mouth is dark. [3] [6]

Biology and ecology

The diet of the mouse catshark consists primarily of shrimp such as Pasiphaea multidentata and Sergestes robustus, other crustaceans such as Dorhynchus thomsoni, bony fishes such as Micromesistius poutassou , and cephalopods. [1] Most prey organisms are captured on or close to the sea floor. [7] Reproduction is oviparous; the female has two oviducts, with one egg maturing inside each at a time. The egg capsules are golden yellow and vase-shaped, measuring 5.4–5.6 cm (2.1–2.2 in) long and 1.4–1.7 cm (0.55–0.67 in) across. The top of the capsule is squared off, while the bottom comes to a short projection. The capsule surface is thickly covered by fibers, giving it a hairy appearance. The young are estimated to hatch at a length of approximately 8–9 cm (3.1–3.5 in). [8]

Human interactions

The mouse catshark is frequently caught incidentally by commercial trawl fisheries operating in deep water off Europe and western Africa. However, it may be small enough to escape most nets, and there are likely parts of its wide range that see little fishing activity. Because there are no substantial threats to its population, the International Union for Conservation of Nature (IUCN) has assessed this species as of Least Concern. [1]

Related Research Articles

<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.

Antilles catshark 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.

Blackmouth catshark Species of shark

The blackmouth catshark is a species of catshark, and part of the family Scyliorhinidae, 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.

Atlantic sawtail catshark Species of shark

The Atlantic sawtail catshark is a little-known species of catshark, part of the family Scyliorhinidae, found in a small area of the northeastern Atlantic Ocean, centered on the Strait of Gibraltar and the Alborán Sea. It is found on or close to the bottom over the continental slope, mostly at depths of 400–600 m (1,300–2,000 ft). This shark closely resembles, and was once thought to be the same species as, the blackmouth catshark ; both are slender with a series of dark saddles and blotches along the back and tail, and a prominent crest of enlarged dermal denticles along the dorsal edge of the caudal fin. It differs subtly from G. melastomus in characters including snout length, caudal peduncle depth, and the color of the furrows at the corner of its mouth.

Roughtail catshark 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.

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).

Longfin sawtail catshark 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.

Gecko catshark Species of shark

The gecko catshark is a species of catshark, part of the family Scyliorhinidae, native to the northwestern Pacific Ocean from southern Japan to Taiwan, and possibly also off Vietnam. It is a common, demersal species found at depths of 100–900 m (330–2,950 ft). Its body is slender, with a pattern of dark saddles and blotches. The dorsal and caudal fins are edged in white, and there is a prominent crest of enlarged dermal denticles along the dorsal edge of the caudal fin. The gecko catshark is a schooling, opportunistic predator of bony fishes, cephalopods, and crustaceans. It is oviparous, with females producing two vase-shaped egg capsules at a time. This species is captured as bycatch, but does not appear to be threatened by fishery activities at present and has been assessed as 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.

Longnose sawtail catshark Species of shark

The longnose sawtail catshark is a little-known species of catshark, part of the family Scyliorhinidae, found off the northwestern Pacific islands of Amami Ōshima, Ogasawara, and Izu at depths of 350–550 m (1,150–1,800 ft). Reaching a length of 80 cm (31 in), it is characterized by a long flattened snout, a long space between the pelvic and anal fins, and a crest of enlarged dermal denticles along the dorsal caudal fin edge. Adults are plain dark gray above, while juveniles have a few faint dark saddles on the back and tail.

Southern sawtail catshark Species of shark

The southern sawtail catshark is a species of catshark, part of the family Scyliorhinidae, endemic to southern Brazil. It inhabits deepwater reefs on the upper continental slope at a depth of 236–600 m (774–1,969 ft). Reaching at least 43 cm (17 in) in length, this slim-bodied species closely resembles the Antilles catshark. It has a prominent crest of enlarged dermal denticles along the dorsal edge of the caudal fin, as well as a distinctive color pattern of dark oval blotches, outlined in white, along its back. The southern sawtail catshark is oviparous, with females producing reddish egg capsules. The International Union for Conservation of Nature (IUCN) has assessed it as Vulnerable; it is often taken as bycatch and may be threatened by intensifying squid fishing.

Broadfin sawtail catshark 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.

Peppered catshark Species of shark

The peppered catshark is a common but little-known species of catshark, part of the family Scyliorhinidae, inhabiting depths of 130–1,326 m (427–4,350 ft) in the northern Gulf of California. It is found on or near the ocean floor, and conducts seasonal migrations, spending winter in deeper water. Reaching a length of 37 cm (15 in), this species has a slender grayish body with a fine covering of black dots. On the dorsal edge of its caudal fin is a prominent crest of enlarged dermal denticles. It is oviparous, with the reproductive period probably lasting from May to September. The International Union for Conservation of Nature (IUCN) has listed the peppered catshark under Least Concern, as it faces no significant threats from human activity.

African sawtail catshark Species of shark

The African sawtail catshark is a species of catshark, part of the family Scyliorhinidae. 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).

Blacktip sawtail catshark 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.

Dwarf sawtail catshark 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.

Springers sawtail catshark Species of shark

Springer's sawtail catshark is a little-known 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.

Longhead catshark 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.

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.

The phallic catshark is a little-known species of catshark, belonging to the family Scyliorhinidae. It is found on or near the ocean floor, in the deep waters off New Caledonia and Vanuatu. A slender species attaining a length of 46 cm (18 in), it is characterized by a long caudal fin bearing a crest of enlarged dermal denticles along the dorsal margin, and very long claspers in adult males. This shark is gray-colored, with four dark saddles along the back and tail.

References

  1. 1 2 3 4 5 6 7 Iglésias, S. (2015). "Galeus murinus". IUCN Red List of Threatened Species . 2015: e.T161705A48941031. doi: 10.2305/IUCN.UK.2015-1.RLTS.T161705A48941031.en . Retrieved 11 November 2021.
  2. ↑ Collett, R. (1904). "Diagnoses of four hitherto undescribed fishes from the depths south of the Faroe Islands". Forhandlinger I Videnskabs-selskabet I Christiania (9): 1–7.
  3. 1 2 3 Compagno, L.J.V. (1988). Sharks of the order Carcharhiniformes. Blackburn Press. pp. 134–142. ISBN   1-930665-76-8.
  4. ↑ Iglésias, S.P.; G. Lecointre & D.Y. Sellos (2005). "Extensive paraphylies within sharks of the order Carcharhiniformes inferred from nuclear and mitochondrial genes". Molecular Phylogenetics and Evolution. 34 (3): 569–583. doi:10.1016/j.ympev.2004.10.022. PMID   15683930.
  5. ↑ Lorance, P., D. Latrouite, and S. Bernard (2000). Observations of Chondrichthyan fishes (sharks,rays and chimaeras) in the Bay of Biscay (North-eastern Atlantic) from submersibles. Proceedings of the 3rd European Elasmobranch Association Meeting, Boulogne-sur-Mer, 1999.
  6. 1 2 Compagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Food and Agricultural Organization. p. 313. ISBN   92-5-101384-5.
  7. ↑ Mauchline, J. & J.D.M. Gordon (1983). "Diets of the sharks and chimaeroids of the Rockall Trough, northeastern Atlantic Ocean". Marine Biology. 75 (2–3): 269–278. doi:10.1007/BF00406012. S2CID   84676692.
  8. ↑ Iglésias, S.P.; M.H. Du Buit & K. Nakaya (2002). "Egg capsules of deep-sea catsharks from eastern north Atlantic, with first descriptions of the capsule of Galeus murinus and Apristurus aphyodes (Chondrichthyes: Scyliorhinidae)". Cybium. 26 (1): 59–63.
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