Overview
An oceanic deep-water species which sometimes comes close to shore [1]. Found surface to depths of at least 150 m [2]. This is an active , almost fearless shark also charged in human attacks [1]. Probably responsible for many open-ocean attacks after air or sea disasters[3].
|
Vulnerable |
|
Interesting Facts
- The Oceanic Whitetip Shark (Carcharhinus longimanus) is one of the most widespread of shark species, ranging across entire oceans in tropical and subtropical waters. The Vulnerable species is subject to fishing pressure virtually throughout its range . It is caught in large numbers as a bycatch in pelagic fisheries, with pelagic longlines, probably pelagic gillnets, handlines and occasionally pelagic and even bottom trawls. Its large fins are highly prized in international trade although the carcass is often discarded. Fishery pressure is likely to persist if not increase in future. Efforts are underway to improve the collection of data from some regions and effective conservation and management of this species will require international agreements. (Ref 100465)
Common Names
Click on the language to view common names.
Common Names in Afrikaans:
Opesee-Wittiphaai
Common Names in Austronesian (Other):
Yeshalifes
Common Names in Carolinian:
Yeshalifes
Common Names in Danish:
Hvidtippet Haj
Common Names in Dutch:
Oceanische Witpunthaai, Witpunthaai
Common Names in English:
Brown Milbert's Sand Bar Shark, Oceanic Whitetip Shark, Brown Shark, Nigano Shark, Oceanic White Tip Shark, Oceanic White-Tip Shark, Oceanic White-Tipped Whaler, Shark, White-Tip Shark, White-tipped Shark, Whitetip, Whitetip Oceanic Shark, Whitetip Shark, Whitetip Whaler
Common Names in Finnish:
Valkopilkkahai
Common Names in French:
Requin Oc?anique, Aileron Blanc Du Large, Rameur, Requin , Requin à Aileron Blanc, Requin à Longues Nageoires, Requin à Nageoires Rondes, Requin à Pointes, Requin Blanc, Requin Canal, Requin Oc, Requin Océan, Requin Océanique
Common Names in German:
Hochsee-Wei, Hochsee-Weißspitzenhai, Langflossen-Hai, Wei, Weißspitzen-Menschenhai, Weißspitzen-Riffhai, Weißspitzenhai
Common Names in Hawaiian:
Manō
Common Names in Italian:
Squalo Alalunga
Common Names in Japanese:
Yogore
Common Names in Jawa:
Cucut Koboy, Hiu Koboy
Common Names in Malay:
Ikan Yu
Common Names in Mandarin Chinese:
大沙, 污斑白眼鮫, 污斑白眼鲛, 長鰭真鯊, 長鰭翼真鯊, 长鳍真鲨, 长鳍翼真鲨
Common Names in Numee:
Kâârrê, KâârrÍ
Common Names in Other:
Pating
Common Names in Polish:
Zarlacz Bialopletwy
Common Names in Portuguese:
Galha-Branca, Marracho, Marracho Oce, Marracho Oceánico, Marracho-De-Pontas-Brancas, Tubar, Tubarão, Tubarão De Pontas Brancas, Tubarão-De-Pontas-Brancas
Common Names in Samoan:
Apoapo
Common Names in Spanish:
Tibur?n Oceanico, Caz, Cazón, Galano, Tibur, Tiburón, Tiburon Negroespinoso, Tiburon Oceanico, Tiburón Pardo
Common Names in Swedish:
Årfenhaj
Common Names in Tagalog:
Pating
Common Names in Tahitian:
Parata
Description
Physical Description
Species Carcharhinus longimanus
Distinctive Features: The oceanic
whitetip shark
is easy to distinguish
among species belonging to the family
Carcharhinidae. This stocky
shark has a large rounded
first dorsal fin and very long and wide
paddle-like pectoral fins. The head
of this shark includes a short
and bluntly rounded nose and small circular eyes that have nictitating
membranes
. The first dorsal fin is very large with a rounded tip,
originating just in front of the free rear tips
of the pectoral fins.
The second dorsal fin originates over or slightly in front of the
anal fin origin
. Possessing broadly rounded tips, the pectoral fins
are very large and elongated.
Dentition: The upper jaw contains broad, triangular, serrated
teeth,
while the teeth in the lower jaw are more pointed
and are only serrated
near the tip
. These teeth, located in powerful jaws
, are effective
at holding and tearing prey
. The arrangement
of the teeth is 14 or
15 on each side of the symphysis
of the upper jaw and 13-15 teeth
on either side of the lower jaw symphysis.
Denticles
: The dermal denticles
of the oceanic whitetip shark lie
almost flat resulting in a smooth
to the touch skin
. The denticles
overlap only slightly with some skin exposed. Usually having 5, but
sometimes 6 or 7, ridges
, the denticles are broader than long.
Color:
This species is commonly named the oceanic whitetip shark for the whitish-tipped first dorsal, pectoral , pelvic , and caudal fins. These white markings are sometimes accompanied by white mottling on the fins or black markings in young individuals. There may also be a dark saddle-shaped marking present between the first and second dorsal fins. The body of the oceanic whitetip shark is grayish bronze to brown in color, varying depending upon geographical location. The underside is whitish with a yellow tinge on some individuals.
Size/Age/Growth
Oceanic whitetip sharks grow to large sizes, with some individuals reaching 11-13 feet (3.5-4 m ). However, most specimens are less than 10 feet (3 m) in length . The maximum recorded weight for this species is 370 pounds (167.4 kg ). Males mature at 5.7-6.5 feet (1.7-1.9 m) in length while females mature at slightly longer sizes of 5.9-6.6 feet (1.8-2.0 m), both corresponding to an age of 6 or 7 years. Females reach greater maximum lengths than males. The longest-lived known specimen lived to an age of 22 years. Males are commonly 270 cm (Total Length) in length when caught/marketed, but may be as large as 396 cm (Total Length).
Habitat
This shark
is usually observed well offshore in deep water
areas
(0-500 feet (0-152 m
)) although on occasion it has been reported
in shallower waters near land
, usually near oceanic islands
. Longline
capture
data
in the Pacific Ocean shows that abundance
of this shark
increases along with distance
from land. It is one of the top three
most abundant oceanic
sharks
, which also include the blue shark (Prionace
glauca) and the silky
shark (Carcharhinus falciformis). The oceanic
whitetip shark is very abundant throughout its range
which includes
water with temperatures
are above 70°F (21°C). Although this
shark is primarily solitary, it has been observed in "feeding
frenzies" when a food source is present. It is a slow swimmer
with equal amounts of activity during the day and nighttime hours.
Reports have described swimming behavior in open waters
at or near
the surface of the water as moving slowly with the huge pectoral
fins
spread
widely.May be found at depths of 0 to 152 meters.
Oceanic whitetip sharks are often accompanied by remoras
, dolphin
fishes
, and pilot fishes. An unusual behavior of the oceanic whitetip
shark is its association with the shortfin pilot whale
(Globicephala
macrorhynchus) in Hawaiian waters as reported by Jeremy Stafford-Deitsch
(1988). They are often observed swimming along with pods of pilot
whales. Although the reason for such behavior is unknown, it is suspected
to be food-related. Pilot whales are efficient at locating squid
upon which the oceanic whitetip sharks also feed
.
Typically found in water with a depth of 0 to -5,685 meters (0 to -18,652 feet).[4]
Ecology:
This is one of the most widespread sharks
, ranging across entire
oceans in tropical
and subtropical
waters. The oceanic
whitetip is
an oceanic-epipelagic shark
, usually found far offshore in the open
sea
in waters >200 m
deep, between about 30°N and 35°S in all
oceans; it is normally found in surface waters, although it has been
recorded to 152 m.
It has occasionally been recorded inshore
, but
is more typically found offshore or around oceanic islands
and areas
with narrow continental shelves (Fourmanoir 1961, Compagno in prep,
Last and Stevens 1994). Temperatures
of waters in which it regularly
occurs are 18 to 28°C, with water above 20°C preferred. Although
one whitetip was caught in water of 15°C it tends to withdraw from
waters that are cooling below this, as in the Gulf
of Mexico in winter
(Compagno in prep.).
This is a slow-moving but quite
active
shark, apparently equally active at daytime or night (Compagno
in prep., Ebert 2003).
Development is viviparous and
embryos have a yolk sac
placenta that attaches to the uterine wall
of the mother (Bigelow and Schroeder 1948). Born at about 60 to 65
cm TL
after a gestation period
of about 10 to 12 months (Compagno
in prep.), males mature
at about 170 to 96 cm and females at 170
to 190 cm TL (Seki et al.
1998). Oceanic whitetip sharks
grow to a large size, with some individual reaching almost 4 m. However,
most known specimens are et al. 1973, Stevens 1984, Seki et al.
1998), although 15 foetuses were recorded from a female of 245 cm
TL from the Red Sea (Gohar and Mazure 1964) and larger females appear
to carry more young, although there may be regional variation
(Bass
et al. 1973). Birth is thought to occur in early summer
in the northwest Atlantic and south west Indian
Oceans (Bass et
al. 1973), and January to March off New South Wales (Stevens
1984), whereas Seki et al. (1998) found that parturition
was February to July in the North Pacific. Pregnant females of this
species are less frequently found in the Indian Ocean than other
sharks of this genus (Gubanov 1978). In the Central Pacific, females
with small embryos have been found throughout the year, suggesting
a less tight seasonality of birth (and presumably mating) than the
Western Atlantic (Compagno in prep). Also, non-breeding adult
females
have been found to outnumber gravid females in the equatorial Central
Pacific (Compagno in prep). The location of nurseries has not been
reported, but very young oceanic whitetip sharks have been found
well offshore along the southeastern US, suggesting offshore nurseries
over the continental shelves (Compagno in prep).
Seki
et al. (1998) studied the age, growth and reproduction
of
the oceanic whitetip in the north Pacific. They found similar growth
rates in both males and females with a Von Bertalanffy equation of:
Lt
= 299.58 * {1 - e-0.103 x
(t + 2.698)} where
Lt is expressed as precaudal length
in cm at age t. They
used Bass et al.?s (1973) transformation
of TL = 1.397 x
PL for conversions to total length. Using vertebral analysis they
showed that annular
formation occurred in spring
. Both male and female
oceanic whitetips matured at 4 to 5 years of age. Smith et al.
(1998) investigated the intrinsic rebound potential of Pacific sharks
and found that oceanic whitetips to be among a moderate rebound potential,
because of their relatively fast growth and early maturation
.
This pelagic species feeds mainly on bony fishes (including
tunas
, barracuda, white marlin, dolphinfish, lancetfish, oarfish,
threadfish, swordfish) and cephalopods
and to a lesser extent, seabirds,
marine
mammals, stingrays, and flotsam
, including garbage. (Ref.
260854).
List of Habitats
:
- 9 Marine Neritic
- 9.8 Marine Neritic - Coral Reef
- 10 Marine Oceanic
- 10.1 Marine Oceanic - Epipelagic (0-200m) [more info]
Biology
Diet
Feeds
on oceanic
bony fishes, also threadfins
, stingrays, sea
turtles,
sea birds, gastropods
, squid, crustaceans, mammalian carrion
and
garbage[5], including tuna
and mahimahi[6][7].
The oceanic whitetip shark
feeds on bony fishes including lancetfish,
barracuda, jacks
, dolphinfish, marlin, tuna, and mackerels
. Other
prey
consists of stingrays, sea turtles, sea birds, gastropods, squid,
crustaceans, and mammalian carrion (dead whales
and dolphins
). Feeding
behavior has been reported for this shark and includes biting into
schools of bony fishes. It also swims
through schools of feeding
tuna with wide-open jaws
into which the tuna unknowingly swim. The
oceanic whitetip shark has also been observed eating garbage that
is disposed of at sea. If other species of sharks
are encountered
by the oceanic whitetip during feeding activities, the oceanic whitetip
becomes aggressive and dominates over them.
Reproduction
Viviparous[8]. There is pronounced partial segregation
by size and sex in some areas.
Records
indicate the oceanic
whitetip shark
mates during the early
summer months in the northwestern Atlantic Ocean and the southwestern
Indian Ocean. This shark is viviparous in reproduction
, meaning the
eggs
hatch
inside the mother with the young being born alive. During
the year-long gestation period
, the embryos are nourished by a placental
yolk-sac
that is attached to the uterine wall by umbilical cords
.
In early summer, a litter
ranging from 1-15 pups
is born. Litter
number is proportional to the size of the mother. Each pup is approximately
24-25.6 inches (60-65 cm) in length
upon birth.
Migration
Oceanodromous .
Behavior
Predators : Large sharks are potential predators of the oceanic whitetip shark , especially immature individuals.
Taxonomy
- Domain:
Eukaryota
(
)
- Whittaker & Margulis,1978
- eukaryotes
- Kingdom:
Animalia
(
)
- C. Linnaeus, 1758
- animals
- Subkingdom:
Bilateria
(
)
- (Hatschek, 1888) Cavalier-Smith, 1983
- Branch:
Deuterostomia
(
)
- Grobben, 1908
- Infrakingdom:
Chordonia
(
)
- (Haeckel, 1874) Cavalier-Smith, 1998
- Phylum:
Chordata
(
)
- Bateson, 1885
- Chordates
- Subphylum:
Vertebrata
(
)
- Cuvier, 1812
- Vertebrates
- Infraphylum:
Gnathostomata
(
)
- auct.
- Jawed Vertebrates
- Class:
Chondrichthyes
(
)
- Subclass:
Elasmobranchii
(
)
- Infraclass:
Euselachii
(
)
- Cohort:
Neoselachii
(
)
- Order:
Carcharhiniformes
(
)
- Family:
Carcharhinidae
(
)
- Jordan & Evermann, 1896
- Genus:
Carcharhinus
(
)
- de Blainville, 1816
- Specific name:
longimanus
- (Poey, 1861)
- Scientific name: - Carcharhinus longimanus (Poey, 1861)
- Specific name:
longimanus
- (Poey, 1861)
- Genus:
Carcharhinus
(
- Family:
Carcharhinidae
(
- Order:
Carcharhiniformes
(
- Cohort:
Neoselachii
(
- Infraclass:
Euselachii
(
- Subclass:
Elasmobranchii
(
- Class:
Chondrichthyes
(
- Infraphylum:
Gnathostomata
(
- Subphylum:
Vertebrata
(
- Phylum:
Chordata
(
- Infrakingdom:
Chordonia
(
- Branch:
Deuterostomia
(
- Subkingdom:
Bilateria
(
- Kingdom:
Animalia
(
Synonyms
Carcharhinus maou (Lesson • Carcharias insularum Snyder • Carcharias longimanus (Poey • Carcharias obtusus Garman • Carcharinus longimanus (Poey • Pterolamiops budkeri Fourmanoir • Pterolamiops longimanus (Poey • Pterolamiops magnipinnis Smith • Squalus longimanus Poey • Squalus maou Lesson
Notes
Name
Status: Accepted Name
.
First described: Poey, F. Memorias sobre la historia natural de
la Isla de Cuba, acompañadas de sumarios Latinos y extractos en
Francés.
Tomo 2. Habana, Imprenta de la Viuda de Barcina 1856-1858. 442
p., 1861.
Last scrutiny: Data
last modified by FishBase 28-Oct-2000
Similar Species
Members of the genus Carcharhinus
ZipcodeZoo has pages for 36 species and subspecies in this genus:
C. acronotus (Blacknose Shark) · C. ahenea (Shortnose Blacktail Shark) · C. albimarginatus (Silvertip Shark) · C. altimus (Knopp´s Shark) · C. amblyrhynchoides (Graceful Shark) · C. amblyrhynchos (Shortnose Blacktail Shark) · C. amboinensis (Ambon Sharpnose Puffer) · C. azureus (Large Blacktip Shark) · C. borneensis (Borneo Mullet) · C. brachyurus (Black-Tipped Whaler) · C. brevipinna (Blacktipped Shark) · C. cautus (Sharks Bay Whaler Shark) · C. dussumieri (Whitecheek Shark) · C. falciformis (Sickle-Shaped Shark) · C. fitzroyensis (Creek Whaler Shark) · C. galapagensis (Galapagos Shark) · C. hemiodon (Pondicherry Shark) · C. isodon (Fintooth Shark) · C. leiodon (Smoothtooth Blacktip Shark) · C. leucas (Bull Shark) · C. limbatus (Blacktip Shark) · C. longimanus (Brown Milbert's Sand Bar Shark) · C. macloti (Hardnose Shark) · C. melanopterus (Black Fin Reef Shark) · C. obscurus (Dusky Shark) · C. perezi (Caribbean Reef Shark) · C. perezii (Caribbean Reef Shark) · C. plumbeus (Northern Whaler Shark) · C. porosus (Tiburon Peninsula Limia) · C. sealei (Black-Spot Shark) · C. signatus (Night Shark) · C. sorrah (West Australian Whaler Shark) · C. springeri (Reef Shark) · C. tilstoni (Australian Blacktip Shark) · C. velox (Whitenose Shark) · C. wheeleri (Blacktail Reef Shark)
More Info
- Search for Pictures: images.google.com
- Search for Scholarly Articles: Google Scholar
- Search using Scientific Name and Vernacular Names: All the Web | AltaVista Canada | AltaVista | Excite | Google | HotBot | Lycos
- Search using Specialized Databases: GenBank | Medline | Scirus | CISTI/CAL | Agricola Periodicals | Agricola Books
Further Reading
- A checklist of Canadian Atlantic fishes with keys for identification / Toronto, Royal Ontario Museum, 1965 url p. 24, p. 4, p. 95.
- A list of common and scientific names of fishes from the United States and Canada. Report presented at the eighty-ninth annual meeting, Clearwater, Fla., Sept. 16-18, 1959. Ann Arbor, Mich., 1960. url p. 7.
- Bulletin of the British Museum (Natural History). London: BM(NH) url p. 164, p. 62.
- California fish and game. [San Francisco, etc.]: State of California, Resources Agency, Dept. of Fish and Game. url p. 131, p. 148, p. 150, p. 253.
- Commercial fisheries review. [Washington]: National Marine Fisheries Service; [for sale by the Supt. of Docs., U.S. Govt. Print. Off.] url p. 31, p. 36, p. 40, p. 48, p. 51.
- Current bibliography for aquatic sciences and fisheries. London, Taylor & Francis ltd. url p. 31.
- Dean bibliography of fishes. New York: American Museum of Natural History, 1971-1973. url p. 184, p. 531, p. 599, p. 648, p. 9.
- Fishery bulletin / U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service. Washington, D.C.: The Service: url p. 163, p. 167, p. 278, p. 288, p. 290, p. 291, p. 346, p. 412, p. 520, p. 794.
- Fishes of the western North Atlantic. Editorial board: editor-in-chief John Tee-Van [and others] New Haven, Sears Foundation for Marine Research, Yale Univ., 1948- url , p. 337, p. 354, p. 355.
- NOAA technical report NMFS SSRF. Seattle, Wash.: National Marine Fisheries Service; url p. 3.
- Oceanus. Woods Hole, Mass., Woods Hole Oceanographic Institution url p. 103, p. 15, p. 23, p. 46.
- Our living oceans: the first annual report on the status of U.S. living marine resources. [Washington, D.C.]: U.S. Dept. of Commerce, 1991. url p. 117.
- Proceedings of the Biological Society of Washington. Washington, Biological Society of Washington url p. 93.
- Proceedings of the California Academy of Sciences, 4th series. San Francisco, California Academy of Sciences. url p. 67.
- Proceedings of the United States National Museum. Washington: Smithsonian Institution Press, [etc.] url p. 2, p. 683.
- Sensory biology of sharks, skates, and rays / editors Edward S. Hodgson, Robert F. Mathewson. Arlington, Va.: Office of Naval Research, Dept. of the Navy: for sale by the Supt. of Docs., U.S. Govt. Print. Off., 1978. url p. 25, p. 566, p. 571, p. 582.
- Shark research: present status and future direction / Bernard J. Zahuranec, editor and workshop convenor. Arlington, Va.: Office of Naval Research. Dept. of the Navy, 1975. url p. 34, p. 6.
- Special scientific report. Seattle, National Marine Fisheries Service; for sale by the Supt. of Docs., U.S. Govt. Print. Off., 1949-1971. url p. 2, p. 4.
- Syllogeus. Ottawa, National Museum of Natural Sciences, 1972-1995. url p. 14.
- The Bulletin of zoological nomenclature. London, International Trust for Zoological Nomenclature. url p. 273.
- The Natural history of Enewetak Atoll / edited by Dennis M. Devaney. .. [et al.]; prepared by Office of Scientific and Technical Information, U.S. Department of Energy. Oak Ridge, Tenn.: U.S. Dept. of Energy, Office of Energy Research, Office of Health and Environmental Research, Ecological Research Division, c1987. url p. 290.
Notes
Contributors
- Baum, J., Medina, E., Musick, J.A. & Smale, M. 2006. Carcharhinus longimanus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloadedon 31January2012.
- Brands, S.J. (comp.) 1989-present. The Taxonomicon. Universal Taxonomic Services, Zwaag, The Netherlands. Accessed January 9, 2012.
- Cathleen Bester. Florida Museum of Natural History
- Compagno, Leonard J.V. (from FishBase).
- FishBase. Release date: January 5, 2010
- Froese, R., and D. Pauly. FishBase 2004. International Center for Living Aquatic Resources Management.
- Global Biodiversity Information Facility. Accessed March 02, 2008. http://www.gbif.org Mediated distribution data from 8 providers.
- IUCN 2012. IUCN Red List of Threatened Species. Version 2011.2. . Downloaded on January 28, 2012.
- Ruggiero M., Gordon D., Bailly N., Kirk P., Nicolson D. (2011). The Catalogue of Life Taxonomic Classification, Edition 2, Part A. In: Species 2000 & ITIS Catalogue of Life: 2011 Annual Checklist (Bisby F.A., Roskov Y.R., Orrell T.M., Nicolson D., Paglinawan L.E., Bailly N., Kirk P.M., Bourgoin T., Baillargeon G., Ouvrard D., eds). DVD; Species 2000: Reading, UK.
Data Sources
Accessed through GBIF Data Portal March 02, 2008:
- FishBase: FishBase DiGIR Provider - Philippine Server
- GBIF-Sweden: Fishes of the Gothenburg Natural History Museum
- Institute of Marine and Coastal Sciences, Rutgers University: Bureau of Rural Sciences National commercial fisheries half-degree data set 2000-2002 (OBIS Australia)
- Institute of Marine and Coastal Sciences, Rutgers University: iziko South African Museum - Shark Collection
- Los Angeles County Museum of Natural History: Vertebrate specimens
- Museum national d'histoire naturelle: Ichtyologie
- Museum of Comparative Zoology, Harvard University: MCZ Fish Collection
- OZCAM (Online Zoological Collections of Australian Museums) Provider: Online Zoological Collections of Australian Museums
- Royal Ontario Museum: Fish specimens
Identifiers
- Biodiversity Heritage Library NamebankID: 3863120
- Catalogue of Life Accepted Name Code: Fis-23061
- Fishbase Species ID: 875
- Global Biodiversity Information Facility Taxonkey: 13529401
- Integrated Taxonomic Information System (ITIS) Taxonomic Serial Number (TSN): 160330
- IUCN ID: 197934
- Zipcode Zoo Species Identifier: 105887
Footnotes
- Compagno, L.J.V. (1984). FAO species catalogue. Vol. 4. Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 2. Carcharhiniformes. FAO Fish. Synop. (125, Vol. 4, Part 2), 655 p. [back]
- Smith, C.L. (1997). National Audubon Society field guide to tropical marine fishes of the Caribbean, the Gulf of Mexico, Florida, the Bahamas, and Bermuda. Alfred A. Knopf, Inc., New York. 720 p. [back]
- Last, P.R. and J.D. Stevens (1994). Sharks and rays of Australia. CSIRO, Australia. 513 p. [back]
- Mean = -2,730.960 meters (-8,959.843 feet), Standard Deviation = 1,601.540 based on 1,332 observations. Ocean depth information for each observation from British Oceanographic Data Centre. [back]
- Compagno, L.J.V., D.A. Ebert and M.J. Smale (1989). Guide to the sharks and rays of southern Africa. New Holland (Publ.) Ltd., London. 158 p. [back]
- Myers, R.F. (1991). Micronesian reef fishes. Second Ed. Coral Graphics, Barrigada, Guam. 298 p. [back]
- Myers, R.F. (1999). Micronesian reef fishes: a comprehensive guide to the coral reef fishes of Micronesia, 3rd revised and expanded edition. Coral Graphics, Barrigada, Guam. 330 p. [back]
- Dulvy, N.K. and J.D. Reynolds (1997). Evolutionary transitions among egg-laying, live-bearing and maternal inputs in sharks and rays. Proc. R. Soc. Lond. B 264:1309-1315. [back]
