Chlamydoselachus anguineus

Geographic Range

Frilled sharks are wide ranging. They have been found almost worldwide, including the eastern Atlantic coast of northern Norway, the western Indian Ocean near South Africa, the western Pacific near New Zealand, and the eastern Pacific near the coast of Chile.

• Biogeographic Regions
• indian ocean
  • native native
• atlantic ocean atlantic ocean
  • native native
• pacific ocean pacific ocean
  • native native

Habitat

Chlamydoselachus anguineus , is found on continental shelves and the nearshore areas of large islands, although they are occasionally reported in open waters. They are mostly benthic and occur at depths from 100 to 1,300 meters.

• Habitat Regions
• temperate temperate
• tropical tropical
• saltwater or marine saltwater or marine

• Aquatic Biomes
• benthic benthic
• coastal coastal

Physical Description

Frilled sharks, or eel sharks (Taylor et al., 2002), have a long slender body with an elongate tail fin, giving them an eel-like appearance (Compagno, 1984). The body tends to be a chocolate brown color. They have a small dorsal fin located well towards the tail, above the large anal fin, and in front of the highly asymmetric caudal fin. The pectoral fins are short and rounded (Taylor et al., 2002). Chlamydoselachus anguineus has six gill openings (most sharks have five). The first gill is continuous across the throat, while all the gills are surrounded by frilly margins of skin-hence the name "frilled shark." The snout is short and the lower jaw is long. The teeth are alike both on the upper and lower jaws, with three elongate, sharp cusps separated by two intermediate ones (Taylor et al., 2002; Nelson, 1994). Length is usually 2 meters (Miller and Lea, 1972).

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Reproduction

Fertilization in all sharks is internal, taking place in the egg tubes or oviducts of the female. Male sharks must grab females, maneuver their bodies so that he can introduce his claspers to pass sperm into the vent. Males and females come together only to mate.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Reproduction in these sharks is not well understood. Chlamydoselachus anguineus is an ovoviviparous shark that can bear anywhere from two to twelve live young (Dulvy & Reynolds, 1997). Young tend to be 40 cm long. Females apparently reproduce all year long and have a gestation period of about one to two years (Compagno, 1984). The size of an immature male is about 730 mm, whereas a mature male is about 970 mm long. Thus, the length of a mature male is anywhere from 730 mm to 970 mm (Nakaya & Bass). Female frilled shark length at maturity is about 1350 mm (Nakaya & Bass).

• Key Reproductive Features
• iteroparous iteroparous
• year-round breeding year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • internal internal
• ovoviviparous ovoviviparous

There is little, if any, information on parental investment in frilled sharks. Sharks in general do not care for their young after their birth (Parker and Parker, 1999).

• Parental Investment
• no parental involvement
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

Frilled sharks have never been kept in captivity. In the wild it is difficult to determine just how long these fish live. Because they are deep benthic creatures there is little information on lifespan. However, one source (Parker and Parker, 1999) estimates maximum lifespan at 25 years.

Behavior

Chlamydoselachus anguineus is a slow-moving, deep water shark. They are among the slowest of shark species (Parker & Parker, 1999). Like most sharks, they are solitary.

• Key Behaviors
• natatorial natatorial
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary

Communication and Perception

There is very little known about the communication and perception of frilled sharks because they live in deep water and are hard to observe. Based on information from other deep water sharks, they probably use their lateral line and sense of touch to navigate along the contours of the sea bed. Deep water sharks are also sensitive to sounds or long-distance vibrations, and to electrical pulses given off by animal muscles. Also, they have the ability to detect changes in water pressure to tell up from down.

• Communication Channels
• acoustic acoustic
• electric electric

• Other Communication Modes
• vibrations vibrations

• Perception Channels
• tactile tactile
• acoustic acoustic
• vibrations vibrations
• chemical chemical
• electric electric

Food Habits

Because of their sharp, cuspidate teeth, it is thought that their primary foods are small deep-water fishes, and squid (Taylor et al., 2002). Because frilled sharks live on the ocean floor, they may also feed on carrion floating down from the surface (Parker & Parker, 1999).

• Primary Diet
• carnivore carnivore
  • piscivore piscivore
  • molluscivore molluscivore
• detritivore detritivore

• Animal Foods
• fish
• carrion carrion
• mollusks
• aquatic crustaceans

Predation

There are few known predators of frilled sharks. Other sharks are likely predators and humans may take these sharks incidentally as fishing bycatch. Becauses they occupy the benthos, they are sometimes caught during bottom trawling or in nets when they venture near the surface.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Frilled sharks are bottom dwellers and may contribute to removing decomposing carcasses. This carrion floats down from the open waters of the ocean above and comes to rest on the ocean floor. Frilled sharks and other benthic decomposers play an important role in recycling nutrients.

• Ecosystem Impact
• biodegradation biodegradation

Economic Importance for Humans: Positive

When frilled sharks are caught as bycatch during net or long line fishing, they may be ground up for fishmeal and fish food. Frilled sharks are unique and fascinating members of oceanic ecosystems.

• Positive Impacts
• food food
• body parts are source of valuable material

Economic Importance for Humans: Negative

These are not dangerous sharks, but their teeth have lacerated the hands of the unwary scientist and or fisherman examining or holding them.

• Negative Impacts
• injures humans
  • bites or stings

Conservation Status

Frilled shark are classified as a near threatened species on the IUCN Red List. There are no current conservation plans for this species (Fowler & Paul).

Other Comments

Today, frilled sharks are the only living species in the family Chlamydoselachidae (Sheikh-Miller, 2001). Scientists also believe that, although frilled sharks rarely come to the surface, they could be the cause for sightings of "sea serpents" because of their unusual, snakelike shape (Twist, 2002).

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Aubrey Lashaway (author), University of Michigan-Ann Arbor, Kevin Wehrly (editor, instructor), University of Michigan-Ann Arbor.

References

Bass, d'Aubrey, & Kistnasamy, , Cadenat & Blache, Compagno, Gudger, Gudger & Smith. 2005. "Figis and FAO" (On-line). Species Fact Sheet: Chlamydoselachus anguineus. Accessed September 24, 2005 at http://www.fao.org/figis/servlet/FiRefServlet?ds=species&fid=11367 .

Compagno, L. 1984. Sharks of the World. FAO Species Catalogue , 4 (1): 14-15.

Dulvy, N., J. Reynolds. 1997.

Evolutionary transitions among egg-laying, live-bearing and maternal inputs in sharks and rays.

Fowler, S., L. Paul. 2004. "Chlamydoselachus anguineus; IUCN Red List of Threatened Species" (On-line). Accessed October 13, 2005 at http://www.redlist.org/search/details.php?species=41794 .

Merriam-Webster, Incorporated, 2005. Merriam-Webster Online Dictionary . Accessed October 19, 2005 at http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=ovoviviparous .

Miller, D., R. Lea. 1972. Guide to the Coastal Marine Fishes of California .

Nakaya, K., A. Bass. 1978. The frill shark Chlamydoselachus anguineus in New Zealand seas. N.Z. Journal of Marine and Freshwater Research , 12 (4): 397-8.

Nelson, J. 1994. Fishes of the World; 3rd Edition . New York, Chichester, Brisbane, Toronto, & Singapore: John Wiley &Sons, Inc.

Parker, J., S. Parker. 1999. The Encyclopedia of Sharks . Canada & United States: Firefly Books Ltd..

Sheikh-Miller, J. 2001. Sharks . 555 Broadway, New York, NY 10012: Scholastic Inc..

Tricas, T., K. Deacon, P. Last, J. McCosker, T. Walker, L. Taylor. 2002. The Nature Companions Sharks and Whales . 814 Montgomery Street, San Francisco CA, 94133 USA: Fog City Press.

Twist, C. 2002. Shark and other sea creatures Dictionary . 557 Broadway, New York, NY 10012: Scholastic and Tangerine Press Inc..