The Philippines angelshark (Squatina caillieti) is a species of angelshark belonging to the family Squatinidae, known only from a 13-inch-long immature female caught in the Philippines. It is a holotype and only known specimen of its family. It can be distinguished by its greenish color with brown spots. One identifying trait is that the spiracles are more widely spaced than the eyes and have papillae the posterior inner rims.
Family: Squatinidae – Angel Sharks
Genus: Squatina
Species: caillieti
Phylum– Chordata
Class– Chondrichthyles
Subclass– Elasmobranchii
Infraclass– Euselachii
Superorder– Selachimorpha
Common Name– Angel Sharks or Angelsharks
Family– Squatinidae
Common Name– Angel Sharks or Angelsharks
Genus– Squatina
Species– caillieti
Status: IUCN Red List NOT EVALUATED
Average Size and Length: The holotype is recorded at 33 cm/ 13 inches long and is an immature female.
Current Rare Mythical Sightings: The holotype (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.
Teeth and Jaw: They have expendable necks and trap-like jaws that can rapidly snap upwards and hinge shut. 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.
Head: The head is flattened. The horizontal edges of the broad, rounded head have 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 barbels do not have fringe. The eyes are horizontally oval and placed relatively close together. Behind the eyes are crescent-shaped spiracles, which are spaced further apart than the eyes and bear prominent papillae along their posterior inner rims. The five pairs of gill slits are laterally situated on the head.
Denticles: 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. It does not have enlarged thorns along the middle of its back.
Tail: The caudal peduncle is flattened and expanded laterally to form keels. The lower lobe of the caudal fin is markedly larger than the upper.
Demographic, Distribution, Habitat, Environment and Range: The holotype of the Philippines angelshark specimen was collected by trawl from a depth of 1,191–1,263 feet, southeast of the island of Luzon. It is the only species of angel shark known to occur in the Philippines.
Ram-Suction Index: They have an RSI more towards the suction end of the scale. They lay flat and still on the bottom, when the time comes, they lung at prey and suck it into their mouths with negative pressure.
Aesthetic Identification: Like other Angel sharks, the Philippines angelshark has a flattened, ray-like body with greatly enlarged pectoral and pelvic fins. The Philippines angelshark is greenish brown above with many round, pale-edged brown spots. It has black saddles below the dorsal fin bases, and white pelvic fin edges. It is plain white ventrally. There are no ocelli. 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.
Biology and Reproduction: Not much is known about the biology or reproduction of the Philippines angelshark, but they are presumably ovoviviparous.
Behavioral Traits, Sensing and Intelligence: The Philippines angelshark lies semi-buried in the sand or on the muddy bottom waiting and ready to ambush prey. They can remain still on the bottom for extremely long and extended periods of time.
Philippines angelsharks have a unique way of breathing compared to most other benthic sharks and fish. They do not pump out water from the oropharyngeal cavity. Instead, they use gill flaps located on the sides of their body to pump out water during respiration. Doing so also allows them to be more unnoticeable and prevent detection from unwanted predators.
Philippines Angelshark Future and Conservation: There is not enough data to evaluate.
Philippines Angelshark Recorded Attacks on Humans: Philippines angelsharks aren’t dangerous to humans unless provoked. Because of their powerful jaws and sharp teeth, they can inflict injury on anyone or anything that may pose a threat to them. There have been cases of Angel sharks biting divers that have tried to restrain them, approach too close to the head, corner them, or grab their tails.
Walsh, J.H., D.A. Ebert and L.J.V. Compagno (2011). “Squatina caillieti sp. nov., a new species of angel shark (Chondrichthyes: Squatiniformes: Squatinidae) from the Philippine Islands” (PDF). Zootaxa. 2759: 49–59