Longfin sawtail cat shark
Encyclopedia
The longfin sawtail catshark (Galeus cadenati) is a rare, little-known species
of catshark
, family
Scyliorhinidae. Once thought to be a subspecies
of the roughtail catshark
(G. arae) along with the Antilles catshark
(G. antillensis), 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 (13.8 in). The longfin sawtail catshark is oviparous. The International Union for Conservation of Nature (IUCN) currently lacks the data to assess its conservation status.
described the longfin sawtail catshark in a 1966 issue of the United States Fish and Wildlife Service Fishery Bulletin, based on a 31 cm (12.2 in) long female collected off Panama on May 30, 1962. He named the species after French zoologist Jean Cadenat, who described the similar African sawtail catshark
(G. polli). Springer and other authors would subsequently come to regard G. cadenati as a subspecies
of the roughtail catshark
(G. arae). In 1998 and 2000, Hera Konstantinou and colleagues published revisions of the G. arae species complex
in which they elevated G. a. cadenati back to the rank of full species, along with the other subspecies G. a. antillensis.
off Panama
and Colombia
, though confusion with its sister species could have obscured the full extent of its distribution. Demersal in nature, it is a rare inhabitant of the upper continental slope, at depths of 431 to 549 m (1,414 to 1,801.2 ft).
s (protective third eyelids), and lack prominent ridges underneath. A modest spiracle
is located behind each eye. The nostrils are large and partially covered by anterior triangular flaps of skin. The mouth is wide and curved, with fairly long furrows around the corners. The teeth have a long central cusp flanked on either side by one or two pairs of lateral cusplets. The upper jaw of the type specimen contained 62 tooth rows. The five pairs of gill slit
s are small, with the fourth and fifth pairs located over the pectoral fin bases.
The two dorsal fin
s are similar in size and shape, with blunt apexes. The first dorsal fin originates over the midpoint of the pelvic fin bases, while the second originates over the midpoint of the anal fin base. The pectoral fins are large and broad, with rounded corners. The pelvic and anal fins are low and angular in shape. The anal fin base is distinctively long compared to the other members of the G. arae complex, measuring 13–16% of the total length. The caudal fin has a small, rounded lower lobe and a ventral notch near the tip of the upper lobe. The body is covered by small, overlapping dermal denticles, each with a leaf-shaped crown bearing a horizontal ridge and three marginal teeth. A series of enlarged denticles form an obvious saw-toothed crest along the anterior dorsal edge of the caudal fin. This species is brownish above, with a marbled pattern of darker saddles and blotches along the body and tail that become indistinct past the origin of the first dorsal fin. The underside is uniformly light, and the inside of the mouth is dark.
, on the right, and two functional oviduct
s. A single egg matures within each oviduct at a time. The egg is enclosed within a flask-shaped capsule roughly 4.9–5.1 cm (1.9–2 in) long, 1.2–1.4 cm (0.47244094488189–0.551181102362205 in) across the top, and 1.6 cm (0.62992125984252 in) across the bottom; there are coiled tendrils at the upper two corners. Females mature
at about 29–34 cm (11.4–13.4 in) long; adult males are unknown and the largest known immature male measured 29 cm (11.4 in) long.
in bottom trawls meant for shrimp
, though no specific information is available. Its small range potentially renders it susceptible to overfishing
. Given a lack of information, the International Union for Conservation of Nature (IUCN) has listed this species as Data Deficient
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of catshark
Catshark
Catsharks are ground sharks of the family Scyliorhinidae, with over 150 known species. While they are generally known as catsharks, many species are commonly called dogfish....
, family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Scyliorhinidae. Once thought to be a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the roughtail catshark
Roughtail catshark
The roughtail catshark or marbled catshark is a common species of catshark, family Scyliorhinidae. It is found at a depth of 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...
(G. arae) along with the Antilles catshark
Antilles catshark
The Antilles catshark is a common but little-known species of catshark, family Scyliorhinidae. It is found on or near the bottom at a depth of 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...
(G. antillensis), it inhabits deep water off the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
coasts of Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
and Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
. 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 (13.8 in). The longfin sawtail catshark is oviparous. The International Union for Conservation of Nature (IUCN) currently lacks the data to assess its conservation status.
Taxonomy
Renowned shark expert Stewart SpringerStewart Springer
Stewart Springer, was a world renowned expert on shark behavior, classification , and distribution of shark populations. There are more than 35 species of sharks, skates, rays, and other animals either classified originally by him or named after him.-Education:Springer was a field naturalist,...
described the longfin sawtail catshark in a 1966 issue of the United States Fish and Wildlife Service Fishery Bulletin, based on a 31 cm (12.2 in) long female collected off Panama on May 30, 1962. He named the species after French zoologist Jean Cadenat, who described the similar African sawtail catshark
African sawtail catshark
The African sawtail catshark is a species of catshark, family Scyliorhinidae. Demersal in nature, it is found at depths of off the western African coast from Morocco to South Africa...
(G. polli). Springer and other authors would subsequently come to regard G. cadenati as a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the roughtail catshark
Roughtail catshark
The roughtail catshark or marbled catshark is a common species of catshark, family Scyliorhinidae. It is found at a depth of 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...
(G. arae). In 1998 and 2000, Hera Konstantinou and colleagues published revisions of the G. arae species complex
Species complex
A species complex is a group of closely related species, where the exact demarcation between species is often unclear or cryptic owing to their recent and usually still incomplete reproductive isolation. Ring species, superspecies and cryptic species complex are example of species complex...
in which they elevated G. a. cadenati back to the rank of full species, along with the other subspecies G. a. antillensis.
Distribution and habitat
The longfin sawtail catshark does not co-occur with either G. arae or G. antillensis. It has only been found in the Caribbean SeaCaribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
off Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
and Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
, though confusion with its sister species could have obscured the full extent of its distribution. Demersal in nature, it is a rare inhabitant of the upper continental slope, at depths of 431 to 549 m (1,414 to 1,801.2 ft).
Description
The longfin sawtail catshark reaches a maximum known length of 35 cm (13.8 in), smaller than G. antillensis and comparable to G. arae. This species is slender, with a broad head and a moderately long, pointed snout. The large eyes are horizontally oval, equipped with rudimentary nictitating membraneNictitating membrane
The nictitating membrane is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten it while maintaining visibility. Some reptiles, birds, and sharks have a full nictitating membrane; in many mammals, there is a small...
s (protective third eyelids), and lack prominent ridges underneath. A modest spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
is located behind each eye. The nostrils are large and partially covered by anterior triangular flaps of skin. The mouth is wide and curved, with fairly long furrows around the corners. The teeth have a long central cusp flanked on either side by one or two pairs of lateral cusplets. The upper jaw of the type specimen contained 62 tooth rows. The five pairs of gill slit
Gill slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of Cartilaginous fish such as sharks, rays, sawfish, and guitarfish. Most of these have five pairs, but a few species have 6 or 7 pairs...
s are small, with the fourth and fifth pairs located over the pectoral fin bases.
The two dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
s are similar in size and shape, with blunt apexes. The first dorsal fin originates over the midpoint of the pelvic fin bases, while the second originates over the midpoint of the anal fin base. The pectoral fins are large and broad, with rounded corners. The pelvic and anal fins are low and angular in shape. The anal fin base is distinctively long compared to the other members of the G. arae complex, measuring 13–16% of the total length. The caudal fin has a small, rounded lower lobe and a ventral notch near the tip of the upper lobe. The body is covered by small, overlapping dermal denticles, each with a leaf-shaped crown bearing a horizontal ridge and three marginal teeth. A series of enlarged denticles form an obvious saw-toothed crest along the anterior dorsal edge of the caudal fin. This species is brownish above, with a marbled pattern of darker saddles and blotches along the body and tail that become indistinct past the origin of the first dorsal fin. The underside is uniformly light, and the inside of the mouth is dark.
Biology and ecology
Little is known of the natural history of the longfin sawtail catshark. Reproduction is oviparous; mature females have a single functional ovaryOvary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
, on the right, and two functional oviduct
Oviduct
In non-mammalian vertebrates, the passageway from the ovaries to the outside of the body is known as the oviduct. The eggs travel along the oviduct. These eggs will either be fertilized by sperm to become a zygote, or will degenerate in the body...
s. A single egg matures within each oviduct at a time. The egg is enclosed within a flask-shaped capsule roughly 4.9–5.1 cm (1.9–2 in) long, 1.2–1.4 cm (0.47244094488189–0.551181102362205 in) across the top, and 1.6 cm (0.62992125984252 in) across the bottom; there are coiled tendrils at the upper two corners. Females mature
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at about 29–34 cm (11.4–13.4 in) long; adult males are unknown and the largest known immature male measured 29 cm (11.4 in) long.
Human interactions
The longfin sawtail catshark may be caught incidentallyBycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
in bottom trawls meant for shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
, though no specific information is available. Its small range potentially renders it susceptible to overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
. Given a lack of information, the International Union for Conservation of Nature (IUCN) has listed this species as Data Deficient
Data Deficient
Data Deficient is a category applied by the IUCN, other agencies, and individuals to a species when the available information is not sufficient for a proper assessment of conservation status to be made...
.