Galeus

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Galeus
Temporal range: Early Miocene–Present [1]
Galeus melastomus Sardinia.jpg
Blackmouth catshark (Galeus melastomus)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Carcharhiniformes
Family: Scyliorhinidae
Genus: Galeus
Cuvier, 1816
Type species
Galeus melastomus
Synonyms
  • Pristiurus (subgenus of Scyllium) Bonaparte, 1834

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. [3] 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.

Contents

Taxonomy

The illustration that accompanied the 1904 description of the mouse catshark, as Pristurus murinus Pristiurus murinus by collett.jpg
The illustration that accompanied the 1904 description of the mouse catshark, as Pristurus murinus

Galeus, derived from the Greek galeos meaning "shark", is one of the oldest carcharhiniform generic names. It was first used in a binomial by Constantine Samuel Rafinesque in his 1810 Caratteri di alcuni nuovi generi e nuove specie di animali (principalmente di pesci) e piante della Sicilia: con varie osservazioni sopra i medesimi. [4] Rafinesque listed G. melastomus, G. vulpecula (= Alopias vulpinus ), G. mustelus (= Mustelus mustelus ), and G. catulus (= Scyliorhinus canicula ). Subsequently, in 1816 Georges Cuvier used Galeus to refer to the genus presently known as Galeorhinus , and in 1818 William Elford Leach used Galeus to refer to genus presently known as Mustelus . As a result, 19th century authors generally used Galeus for the tope sharks, and Pristiurus, coined by Charles Lucien Bonaparte in 1834, for the sawtail catsharks. [3]

Rafinesque might have intended G. mustelus to be the type species for Galeus, but of his listed species he furnished a description only for G. melastomus. Therefore, in 1908 Henry Weed Fowler designated G. melastomus as the type species of Galeus, establishing the genus to contain the sawtail catsharks. [5] Pristiurus became a junior synonym, though it continued to appear in scientific literature for some time after. Fowler's definition of Galeus gained widespread acceptance after Henry Bryant Bigelow and William Charles Schroeder's 1948 taxonomic review. [3] [6] In 1952, Philip Orkin advocated that Pristiurus take precedence over Galeus, based on David Starr Jordan and Barton Warren Evermann's (possibly questionable) designation of G. mustelus as a type species for Galeus in 1896. [7] Leonard Compagno and most other recent authors have not upheld his proposal, in the interests of taxonomic stability. [3]

Species

Phylogeny and evolution

Most taxonomic studies have concluded the closest relatives of Galeus to be Apristurus , Asymbolus , Parmaturus , and/or Cephalurus . [8] Leonard Compagno has placed Galeus with Apristurus, Bythaelurus , Cephalurus, Parmaturus, and Pentanchus in the tribe Pentanchini of the subfamily Pentanchinae, based on morphological characters. [9] Galeus was suggested to be the sister group of Apristurus in a 2005 phylogenetic study based on mitochondrial and nuclear DNA gene sequences, by Samuel Iglésias and colleagues. [8] The affinity between Galeus and Apristurus was also upheld, albeit weakly, in a 2006 phylogenetic analysis based on three mitochondrial DNA genes, by Brett Human and colleagues. [9] Within the genus, though the G. arae species complex, G. atlanticus , G. eastmani , G. melastomus , G. piperatus , G. polli , and G. sauteri definitely form a monophyletic group, the assignment of other species (e.g. G. murinus ) within the genus is more problematic. [3] In the aforementioned study by Iglésias and colleagues, which included five Galeus species, G. eastmani, G. gracilis, and G. sauteri were grouped into one clade and G. melastomus and G. murinus grouped into another. [8] Galeus fossils, dating to the Burdigalian (20.43–15.97 Ma) and Langhian (15.97–13.65 Ma) stages of the early Miocene, have been recovered from France. [1]

Distribution and habitat

A roughtail catshark (G. arae) in its natural habitat. Members of this genus occur close to the bottom in deep water. Catshark oedv2.jpg
A roughtail catshark (G. arae) in its natural habitat. Members of this genus occur close to the bottom in deep water.

The centers of biodiversity for Galeus are the North Atlantic (8 species) and the northwestern Pacific (4 species). A few outlying species are found in the South Atlantic (G. mincaronei and G. polli), Oceania (G. gracilis and G. priapus), and the Gulf of California (G. piperatus). In the western Indian Ocean, this genus appears to be replaced by the ecologically similar genus Holohalaelurus . [3] [10] [11] Sawtail catsharks are demersal in habits and occur in deep water over outer continental and insular shelves and upper slopes. [10] [12]

Description

Sawtail catsharks reach maximum lengths of between 25 and 90 cm (9.8 and 35.4 in). They have slender, firm bodies and narrow, slightly flattened heads with short to long, pointed snouts. The nostrils are divided into incurrent and excurrent openings by triangular flaps of skin on their anterior rims. The horizontally oval eyes are placed mostly on the sides of the head and equipped with rudimentary nictitating membranes (protective third eyelids); below each eye is a subtle ridge, and behind is a small spiracle (auxiliary respiratory opening). The mouth is rather large and wide, and when closed the upper teeth are exposed. There are short to long furrows around the corners of the jaws. The teeth are small and number 47–78 rows in the upper jaw and 48–82 rows in the lower jaw; each tooth has a narrow central cusp flanked by one or more smaller cusplets on either side. There are five pairs of gill slits. [3] [12]

Close-up from above of the caudal fin denticle crest of the longfin sawtail catshark (G. cadenati). Such crests are shared by all Galeus species. Galeus cadenati crest by springer.png
Close-up from above of the caudal fin denticle crest of the longfin sawtail catshark (G. cadenati). Such crests are shared by all Galeus species.

The two dorsal fins are nearly equal in size and shape, and are placed well back on the body, behind the origins of the pelvic fins. The pectoral fins are fairly large and broad, with angular to rounded corners. The pelvic fins are much smaller, and bear claspers in males; in G. murinus and G. nipponensis , the pelvic fin inner margins are partially fused to form an "apron" over the base of the claspers. The anal fin is elongated and much larger than the pelvic and dorsal fins; its position relative to the pelvic and caudal fins varies from very close to well-spaced. The caudal peduncle can be nearly cylindrical to laterally compressed, depending on species. The caudal fin comprises more or less a quarter of the total length, and is low with a small lower lobe and a ventral notch near the tip of the upper lobe. [3] [12] [13]

The skin is thick and densely covered by small, overlapping, well-calcified dermal denticles; each denticle has a leaf-shaped crown with a horizontal ridge and three teeth on the posterior margin. There is a prominent, saw-like crest of enlarged denticles along the dorsal margin of the caudal fin. G. murinus and G. springeri also have a similar crest along the ventral margin of the caudal fin. Galeus species are typically grayish or brownish above and lighter below, and most have a pattern of darker saddles and/or blotches along the back and tail. The interior of the mouth may be light or dark. [3] [12] [14]

Biology and ecology

Natural history data is scant for most Galeus species. They feed on various types of invertebrates and fishes on or near the bottom. [10] In Suruga Bay, the dietary compositions of G. eastmani and juvenile G. nipponensis differ significantly, suggesting there is reduced interspecific competition between co-occurring Galeus species. [15] Reproductive modes within the genus are notably diverse: while most species are oviparous and lay encapsulated eggs on the sea floor, there is a single aplacental viviparous species ( G. polli ) that retains eggs internally and gives live birth. Among the oviparous species, most (e.g. G. murinus, G. nipponensis) exhibit single oviparity, in which only a single egg matures within each of the female's oviducts at a time. In contrast, a few species such as G. atlanticus and G. melastomus exhibit multiple oviparity, in which several eggs can mature within each oviduct simultaneously. Single oviparity is considered to be the basal condition, while multiple oviparity and aplacental viviparity are thought to be more derived. [16]

Human interactions

Sawtail catsharks pose no danger to humans and have little economic value, though varying numbers are caught incidentally by deepwater commercial fisheries. Some of the larger species, such as G. melastomus and G. polli, are occasionally utilized for meat, fishmeal, and/or leather. [12] The International Union for Conservation of Nature (IUCN) has listed G. atlanticus and G. mincaronei , both of which have very restricted distributions, as Near Threatened and Vulnerable respectively. [17] [18]

Related Research Articles

<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">Blackmouth catshark</span> 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.

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

<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

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).

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

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

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

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

The mouse catshark 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".

<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

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.

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

<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">Northern sawtail catshark</span> 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.

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

  1. 1 2 Marsili, S. (2007). "A new bathyal shark fauna from the Pleistocene sediments of Fiumefreddo (Sicily, Italy)" (PDF). Geodiversitas. 29 (2): 229–247. Archived from the original (PDF) on 2011-06-12.
  2. ↑ Rafinesque, C.S. (1810). Caratteri di alcuni nuovi generi e nuove specie di animali e piante della Sicilia, con varie osservazioni sopra i medisimi. (Part 1 involves fishes, pp. [i-iv] 3-69, Part 2 with slightly different title, pp. ia-iva + 71-105). Pls. 1-20.
  3. 1 2 3 4 5 6 7 8 9 Compagno, L.J.V. (1988). Sharks of the Order Carcharhiniformes. Blackburn Press. pp. 134–142. ISBN   1-930665-76-8.
  4. ↑ "Characters of various new genera and species of animals (mostly fishes) and plants, with various observations about them"
  5. ↑ Fowler, H.W. (1908). "Notes on sharks". Proceedings of the Academy of Natural Sciences of Philadelphia. 60: 52–70.
  6. ↑ Bigelow, H.W.; W.C. Schroeder. "Sharks". Memoirs of the Sears Foundation of Marine Research. 1: 53–576.
  7. ↑ Orkin, P.A. (December 1952). "Galeus Rafinesque, 1810 (Chondrichthyes, Triakidae), an invalid generic name". Annals and Magazine of Natural History. 5 (60): 1112. doi:10.1080/00222935208654389.
  8. 1 2 3 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.
  9. 1 2 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.
  10. 1 2 3 Compagno, L.J.V.; M. Dando & S. Fowler (2005). Sharks of the World. Princeton University Press. pp. 223–232. ISBN   978-0-691-12072-0.
  11. ↑ Séret, B.; P.R. Last (June 30, 2008). "Galeus priapus sp. nov., a new species of sawtail catsharks (Charcharhiniformes: Scyliorhinidae) from New Caledonia". Zootaxa. 1813: 19–28. doi:10.11646/zootaxa.1813.1.2.
  12. 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. Food and Agricultural Organization. pp. 306–318. ISBN   92-5-101384-5.
  13. ↑ Nakaya, K. (1975). "Taxonomy, comparative anatomy and phylogeny of Japanese catsharks, Scyliorhinidae". Memoirs of the Faculty of Fisheries, Hokkaido University. 23: 1–94.
  14. ↑ Konstantinou, H.; J.R. Cozzi (1998). "Galeus springeri, a new species of sawtail catshark from the Caribbean Sea (Chondrichthys, Scyliorhinidae)". Copeia. 1998 (1): 151–158. doi:10.2307/1447711. JSTOR   1447711.
  15. ↑ Horie, T.; S. Tanaka (2000). "Reproduction and food habits of two species of sawtail catsharks, Galeus eastmani and G. nipponensis, in Suruga Bay, Japan". Fisheries Science. 6 (5): 812–825. doi: 10.1046/j.1444-2906.2000.00133.x .
  16. ↑ 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.
  17. ↑ Coelho, R.; J. Rey; F. Serena & C. Mancusi (2007). "Galeus atlanticus". IUCN Red List of Threatened Species . 2007: e.T63149A12623555. doi: 10.2305/IUCN.UK.2007.RLTS.T63149A12623555.en . Retrieved 14 January 2018.
  18. ↑ Rincon, G. (2004). "Galeus mincaronei". IUCN Red List of Threatened Species . 2004: e.T44578A10921845. doi: 10.2305/IUCN.UK.2004.RLTS.T44578A10921845.en . Retrieved 14 January 2018.
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