Squatina caillieti
Encyclopedia
Squatina caillieti is a species
of angel shark
, family
Squatinidae, known only from a 33 cm (13 in) long immature female caught in the Philippines
, where it is the only known representative of its family. It has a flattened body and head with greatly expanded pectoral and pelvic fins, and is greenish above with brown spots. Identifying traits of this species include the spiracle
s, which are more widely spaced than the eyes and bear papillae (nipple-shaped structures) on the posterior inner rims, and the relative positions of the two dorsal fin
s. Additionally, S. caillieti lacks fringes on its barbels, enlarged thorns along the middle of its back, and ocelli
("eyespots") on its fins.
(and only known specimen) of S. caillieti is an immature female collected on September 23, 1995 by Leonard Compagno
and Peter Last. It was originally identified tentatively as a Taiwan angelshark
(S. formosa), before being described as a new species by Jonathan Walsh, David Ebert, and Leonard Compagno in a 2011 issue of the scientific journal
Zootaxa
. It was named in honor of ichthyologist Gregor Cailliet, particularly known for his studies of growth and aging in cartilaginous fishes.
. It is the only species of angel shark known to occur in the Philippines.
-like form with greatly enlarged pectoral and pelvic fins. The horizontal edges of the broad, rounded head bear enlarged folds of skin. The large nostrils are teardrop-shaped and preceded by flaps of skin enlarged into two cylindrical barbels that overhang the mouth. The eyes are horizontally oval and placed relatively close together. Behind the eyes are crescent-shaped spiracle
s, which are spaced further apart than the eyes and bear prominent papillae (nipple-shaped structures) along their posterior inner rims. The mouth is wide and terminally placed on the snout, with furrows at the corners and the center of the upper lip forming a rounded arch. The upper and lower jaws contain 10 and 9 tooth rows respectively on either side; the teeth are small, conical, and sharp. The five pairs of gill slit
s are laterally situated on the head.
The pectoral fins have straight leading margins and rounded outer corners, that form an angle slightly over 120°. The anterior lobes of the pectoral fins are free from the head. The pelvic fins are roughly triangular and about three-quarters as long as the pectoral fins; the pelvic fin rear tips are approximately even with the origin of the first dorsal fin
. The two dorsal fins are similar in shape, with the first slightly larger than the second. Both have straight leading margins and somewhat angular apexes. The space between the dorsal fins is greater than the space between the second dorsal and caudal fins. The caudal peduncle is flattened and expanded laterally to form keels. The lower lobe of the caudal fin is markedly larger than the upper. A moderately rough covering of dermal denticles is present over the upper surface and both dorsal fins; the underside is mostly smooth, except along the pectoral and pelvic fin margins. This species is greenish brown above with many round, pale-edged brown spots, black saddles below the dorsal fin bases, and white pelvic fin edges. It is plain white below. The sole specimen measures 33 cm (13 in) long.
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 angel shark
Angel shark
The angel sharks are an unusual genus of sharks with flattened bodies and broad pectoral fins that give them a strong resemblance to rays. The more than 16 known species are in the genus Squatina, the only genus in its family, Squatinidae, and order Squatiniformes. They occur worldwide in temperate...
, 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...
Squatinidae, known only from a 33 cm (13 in) long immature female caught in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, where it is the only known representative of its family. It has a flattened body and head with greatly expanded pectoral and pelvic fins, and is greenish above with brown spots. Identifying traits of this species include the 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...
s, which are more widely spaced than the eyes and bear papillae (nipple-shaped structures) on the posterior inner rims, and the relative positions of 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. Additionally, S. caillieti lacks fringes on its barbels, enlarged thorns along the middle of its back, and ocelli
Eyespot (mimicry)
An eyespot is an eye-like marking. They are found on butterflies, reptiles, birds and fish. In members of the Felidae family , the white circular markings on the backs of the ears are termed ocelli, and they are functionally similar to eyespots in other animals.Eyespots may be a form of...
("eyespots") on its fins.
Taxonomy
The holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
(and only known specimen) of S. caillieti is an immature female collected on September 23, 1995 by Leonard Compagno
Leonard Compagno
Leonard Joseph Victor Compagno is an international authority on shark taxonomy and the author of many scientific papers and books on the subject, best known of which is his 1984 catalogue of shark species produced for the Food and Agriculture Organization of the United Nations.-Career:*Ph.D,...
and Peter Last. It was originally identified tentatively as a Taiwan angelshark
Taiwan angelshark
The Taiwan angelshark, Squatina formosa, is an angel shark of the family Squatinidae found around Taiwan between latitudes 24° N and 22° N, at depths of between 185 and 220 m...
(S. formosa), before being described as a new species by Jonathan Walsh, David Ebert, and Leonard Compagno in a 2011 issue of the scientific journal
Scientific journal
In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. There are thousands of scientific journals in publication, and many more have been published at various points in the past...
Zootaxa
Zootaxa
Zootaxa is a peer-reviewed scientific journal for animal taxonomists. It is published by Magnolia Press . The journal was established by Zhi-Qiang Zhang in 2001 and new issues are published multiple times a week...
. It was named in honor of ichthyologist Gregor Cailliet, particularly known for his studies of growth and aging in cartilaginous fishes.
Distribution and habitat
The single S. caillieti specimen was collected by trawl from a depth of 363–385 m (1,190.9–1,263.1 ft), southeast of the island of LuzonLuzon
Luzon is the largest island in the Philippines. It is located in the northernmost region of the archipelago, and is also the name for one of the three primary island groups in the country centered on the Island of Luzon...
. It is the only species of angel shark known to occur in the Philippines.
Description
Like other angel sharks, S. caillieti has a flattened, rayBatoidea
Batoidea is a superorder of cartilaginous fish commonly known as rays and skates, containing more than 500 described species in thirteen families...
-like form with greatly enlarged pectoral and pelvic fins. The horizontal edges of the broad, rounded head bear enlarged folds of skin. The large nostrils are teardrop-shaped and preceded by flaps of skin enlarged into two cylindrical barbels that overhang the mouth. The eyes are horizontally oval and placed relatively close together. Behind the eyes are crescent-shaped 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...
s, which are spaced further apart than the eyes and bear prominent papillae (nipple-shaped structures) along their posterior inner rims. The mouth is wide and terminally placed on the snout, with furrows at the corners and the center of the upper lip forming a rounded arch. The upper and lower jaws contain 10 and 9 tooth rows respectively on either side; the teeth are small, conical, and sharp. 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 laterally situated on the head.
The pectoral fins have straight leading margins and rounded outer corners, that form an angle slightly over 120°. The anterior lobes of the pectoral fins are free from the head. The pelvic fins are roughly triangular and about three-quarters as long as the pectoral fins; the pelvic fin rear tips are approximately even with the origin of the first 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...
. The two dorsal fins are similar in shape, with the first slightly larger than the second. Both have straight leading margins and somewhat angular apexes. The space between the dorsal fins is greater than the space between the second dorsal and caudal fins. The caudal peduncle is flattened and expanded laterally to form keels. The lower lobe of the caudal fin is markedly larger than the upper. A moderately rough covering of dermal denticles is present over the upper surface and both dorsal fins; the underside is mostly smooth, except along the pectoral and pelvic fin margins. This species is greenish brown above with many round, pale-edged brown spots, black saddles below the dorsal fin bases, and white pelvic fin edges. It is plain white below. The sole specimen measures 33 cm (13 in) long.