page_title: Frilled shark
section_title: Description
hierarchical_section_title: Frilled shark / Description
context_page_description: The frilled shark and the southern African frilled shark are the two extant species of shark in the family Chlamydoselachidae. The frilled shark is considered a living fossil, because of its primitive, anguilliform physical traits, such as a dark-brown color, amphistyly, and a 2.0 m –long body, which has dorsal, pelvic, and anal fins located towards the tail. The common name, frilled shark, derives from the fringed appearance of the six pairs of gill slits at the shark's throat.
  The two species of frilled shark are distributed throughout regions of the Atlantic and the Pacific oceans, usually in the waters of the outer continental shelf and of the upper continental slope, where the shivers usually live near the ocean floor, near biologically productive areas of the ecosystem. To live on a diet of cephalopods, smaller sharks, and bony fish, the frilled shark practices diel vertical migration to feed at night at the surface of the ocean. When hunting food, the frilled shark moves like an eel, bending and lunging to capture and swallow whole prey with its long and flexible jaws, which are equipped with 300 recurved, needle-like teeth.
context_section_description: The eel-like bodies of the Chlamydoselachus anguineus and the Chlamydoselachus africana species of frilled shark are anatomically different; the anguineus frilled shark has a longer head and shorter gill slits; a spinal column with more vertebrae (160–171 vs. 147); and a lower-intestine spiral valve with more turns (35–49 vs. 26–28) than does the africana frilled shark; moreover, the skin color of the frilled shark is either uniformly dark-brown or uniformly grey. The recorded, maximum body-length of a male frilled shark is 1.7 m (5.6 ft), and the recorded, maximum body-length of a female frilled shark is 2.0 m (6.6 ft).
  The head of the frilled shark is broad and flat, with a short, rounded snout. The nostrils are vertical slits, separated by a flap of skin that forms the incurrent opening and the excurrent opening. The moderately large eyes are horizontal ellipsoids, which have no nictitating membrane, which is a protective, third-eyelid. Ligaments articulate the long jaws to the cranium,  and the corners of the mouth have neither furrows nor folds. The jaws contain 300 trident-shaped teeth, each needle-tooth has a cusp and two cusplets; the rows of teeth are widely spaced, with 19–28 tooth rows in the upper jaw, and 21–29 tooth rows in the lower jaw. At the throat, there are six pairs of long gill slits; the first pair of gill slits form a collar, while the extended tips of the gill filaments create a fleshy frill, hence, the frilled shark name of this fish.
  The pectoral fins are short and rounded; the single, small dorsal fin has a rounded margin, and is positioned at the far end of the body, approximately opposite the anal fin. The pelvic and the anal fins are large, broad, and rounded, and are positioned to the tail-end of the frilled shark's body. The very long caudal fin is a triangular tail that has neither a lower lobe nor a ventral notch in the upper lobe, and has a margin equipped with sharp, chisel-shaped dermal denticles, which the shark can enlarge. The underside of the shark's eel-like body features a pair of long, thick folds of skin, separated by a groove, which run the length of the belly; the function of the ventral skin-folds is unknown. In the female frilled shark, the mid-section is of the body longer, with the pelvic fins located closer to the anal fin.
caption: The frilled shark's lower jaw has 21–29 rows of recurved, needle-like teeth, for snagging, capturing, and eating soft-bodied cephalopods, small sharks, and bony fish.
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