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Topic: Carcharhinids

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	Carcharhinidae: Whaler Sharks
		A typical carcharhinid, the Blacktip Shark (Carcharhinus [Aprionodon] limbatus) conforms to the popular conception of a 'typical' shark.
		The 57 or so species of carcharhinids are generally largish (most between 3 and 10 feet, or 1 and 3 metres, long), solidly-built sharks with few obvious distinguishing features, making it difficult to tell one species from another (among the cognoscente, they are often referred to as the "confusing carcharhinids").
		It grows to over seven times as massive as any carcharhinid, has unique slit-like spiracles, unique cockscomb-shaped teeth, and is the only member of the family that is not placentally viviparous.
	www.elasmo-research.org /education/shark_profiles/carcharhinidae.htm (2012 words)

	Why the hammerhead shark's head is in the shape it's in
		The enhanced electrosensory hypothesis states that the wider head would sample a greater area, but there would need to be a corresponding increase in the number of electrosensory pores over the wider head area to maintain comparable spatial resolution of small, prey-generated electric fields.
		Head morphology, pore number and pore density are quantifiable factors to test the assumption and predictions of the enhanced electrosensory hypothesis in hammerhead sharks.
		This study describes and quantifies the behavioral responses of a sphyrnid and a carcharhinid shark to test the predictions of the enhanced electroreception hypothesis.
	www.eurekalert.org /pub_releases/2002-08/aps-wth082202.php (1779 words)

	Journal of Aquariculture & Aquatic Sciences Article
		The swimming habits of three carcharhinid sharks, a tiger shark (Galeocerdo cuvieri (Peron and Lesueur)), a bull shark (Carcharhinus leucas (Valenciennes)), and brown shark (Carcharhinus plumbeus (Nardo)) cohabitating at The Living Seas Pavilion, EPCOT Center, were observed over a nine month period.
		The study of carcharhinids in an extremely large, yet controlled environment, may yield a better understanding of spatial regulation, as well as the effects of various stimuli on established swimming habits.
		The established carcharhinid population since 1986 consisted of a female tiger shark, _Galeocerdo cuvier_, (LeSueur) (3.4 m total length (TL) and weight 214 kg), one male bull shark, Carcharhinus leucas, (Valenciennes) (2.4 m TL and 158 kg), and one female brown shark, Carcharhinus plumbeus, (Nardo) (2.0 m TL and 57 kg).
	www.petsforum.com /cis-fishnet/JAAS/D082.htm (2594 words)

	research
		We have compared the olfactory system morphology of sphyrnid sharks to their closely related carcharhinid relatives to see if this hypothesis is supported.
		Most sphyrnid sharks possess a distinct prenarial groove on the anterior edge of the cephalofoil that serves to channel water from along the length of the groove into the nostrils.
		The surface area of the lamellae that comprise the olfactory rosette was compared among sphyrnid and carcharhinid sharks.
	www.science.fau.edu /sharklab/pages/olfaction_res.html (253 words)

	Makos on TV
		The central nucleus of the dorsal pallium (in the telecephalon) is known to play a part in visual discrimination in nurse sharks, and the central nucleus as a whole is believed to control complex behaviours and "multimodal sensory integration".
		In carcharhinids and sphyrnids, the telecephalon is esp. large, which seems to fit with their apparent complex social and territorial behaviour.
		In carcharhinids and sphyrnids, the % is 51 and 52, respectively.
	dml.cmnh.org /1997Aug/msg00202.html (769 words)

	Why the hammerhead shark's head is in the shape it's in
		Methodology: Head morphology and the distribution of electrosensory pores were compared between a carcharhinid, Carcharhinus plumbeus, and two sphyrnid sharks, Sphyrna lewini and S. tiburo.
		Study 2: Maneuvering in carcharhinid and sphyrnid sharks: the role and non-roll of the hammerhead shark cephalofoil
		Results: Although the hammerheads were more maneuverable, further investigation revealed that they do not roll their body during turns, negating the possibility that the cephalofoil acts as a steering wing.
	www.light-science.com /hammerhead.html (1895 words)

	Great White Sharks (Site not responding. Last check: 2007-10-13)
		Tropical carcharhinids, with some exceptions, are difficult to identify in the water, and the ratio of positive identifications of species of these sharks involved in attacks to numbers of tropical shark attacks is very low.
		Therefore there might very well be tropical carcharhinids, particularly the tiger and bull sharks, that may be equally as dangerous or more dangerous than the white shark, but this remains to be seen.
		Although much has been made of white shark attacks in the popular newsmedia, the attack rate is very low, far less than drownings, diving accidents, automobile accidents, lightning strokes, or other calamities that afflict humans in the countries where white shark attacks occur.
	schoolweb.missouri.edu /ashland.k12.mo.us/nick/aawebpag.htm (1248 words)

	Tourism and Jaws
		Like Carcharhinids drawn to the carcass of a dying whale, sharks have attracted tourists to various destinations on our planet, for centuries.
		The various interactions between recreating humans and the charismatic carcharhinids in their natural environment can be simply categorized as The Good, the Bad and the Ugly (with thanks to Clint Eastwood).
		Good interactions between tourism and sharks are those that tend to enhance public education regarding the species, such as aquarium and museum displays; those that increase our knowledge of the species, such as sport fishing tag and release programs; and those that include observing sharks in their natural settings.
	www.pacfish.org /sharkcon/documents/gaffneyr.html (2355 words)

	SciTecLibrary - Scientific News (Site not responding. Last check: 2007-10-13)
		tiburo; and a representative carcharhinid, the sandbar shark, Carcharhinus plumbeus.
		Head morphology and the distribution of electrosensory pores were compared between a carcharhinid, Carcharhinus plumbeus, and two sphyrnid sharks, Sphyrna lewini and S. tiburo.
		Although the hammerheads were more maneuverable, further investigation revealed that they do not roll their body during turns, negating the possibility that the cephalofoil acts as a steering wing.
	www.sciteclibrary.ru /eng/catalog/pages/3550.html (1778 words)

	Request for Shark Tissue Samples (Site not responding. Last check: 2007-10-13)
		We have good genetic representation of the more common carcharhinids and sphyrnids of the western North Atlantic and from Western Australia (the latter thanks to Rory McCauly).
		To continue and extend this work, we request shark tissue samples from as many shark species and geographic regions as possible.
		Although we are grateful to receive samples from any shark species, presently, we are particularly interested in obtaining samples from the following carcharhinids and sphyrnids:
	www.elasmo-research.org /research/tissue_samples.htm (461 words)

	Shark Diving International: Dusky Shark Diving (Site not responding. Last check: 2007-10-13)
		Coloration: Typical of many of the carcharhinids, the dusky shark is bluish gray above and white below.
		As with other carcharhinids, developing embryos are nourished via a pseudo-placental sac, a reproductive strategy known as viviparity.
		In the western Atlantic, the number of young per liter ranges from 6-10 with an average of 8, whereas in the southeastern Atlantic, numbers are slightly higher (range 6-14, average 10).
	www.seesharks.com /data-duskyshark.html (1312 words)

	Hammerhead sharks description
		They feed on a variety of fishes including skates, rays, and other hammerheads, and large hammerheads have been known to attack and eat humans without provocation.Geneticist Andrew Martin used mtDNA sequence data to explore the origins and pattern of hammer development in seven species (including two sub-species) of hammerhead shark.
		Martin's results supported the common-sense idea that the hammerheads constitute a monophyletic group (sharing a common ancestor) derived from the carcharhinids, but also revealed some surprises.
		The molecular data strongly suggest that the Winghead Shark - not the Bonnethead - was the first hammerhead to diverge from the group's common ancestor and that the bonnethead was, in fact, the most recent hammerhead to appear.
	www.sharktoothgifts.com /hammerheadshark.htm (449 words)

	Florida Museum of Natural History Ichthyology Department: Sandbar Shark (Site not responding. Last check: 2007-10-13)
		Due to the high percentage of sharks found with partially full stomachs and their relatively large liver, which contains high percentage of oil and vitamins, it is believed that these sharks have a very successful feeding strategy and receive a more regular supply of food than other carcharhinids.
		During this time, a mature male persistently follows a female, occasionally biting the area between her dorsal fins until she turns over allowing him to insert one clasper into the cloaca.
		This form of courtship behavior, which is present in most carcharhinids, often leaves the female with permanent scaring.
	www.flmnh.ufl.edu /fish/Gallery/Descript/Sandbarshark/sandbarshark.htm (1801 words)

	Bull sharks, Carcharhinus leucas
		Their broad, short snout is a very easy way to identify this species.
		They tend to swim more sluggishly than other carcharhinids, occasionally forming packs to feed.
		Nevertheless, bulls tend to be loners (as demonstrated by collection evidence and personal observation).
	www.sharkwrangler.com /pages/bull.htm (362 words)

	BlackTipShark
		Do leave the upper area and a good part of the bottom open free and clear however as carcharhinids need room to move...
		What is called for are slow, deliberate motions, multiple nets/friends, damp towels to hold onto, and if necessary, lift the specimen/s from the water.
		This common small carcharhinid is often seen in the wild, despite its popular use as a food fish.
	www.wetwebmedia.com /blacktipshark.htm (1150 words)

	Hammerhead shark (Site not responding. Last check: 2007-10-13)
		Since Sharks do not have mineralized bones and fossilize it is their teeth alone that commonly found as fossils.
		The hammerheads seem related to the Carcharhinid sharks that evolved the mid- Tertiary but the teeth of hammerheads resemble of some Carcharhinids making it difficult to certain when the hammerheads first appeared.
		It probable that the hammerheads evolved during the Eocene Oligocene or early Miocene.
	www.freeglossary.com /Hammerhead_shark (319 words)

	CSIRO PUBLISHING - Marine & Freshwater Research
		Valuable information on maturity and reproductive status can be obtained by the measurement of the concentrations of steroid hormones in the serum of captive carcharhinid sharks.
		These periodicities suggest, for placental sharks, that consistently rising oestradiol concentrations may set in motion preovulatory events, that testosterone may be important for the initiation of subsequent ovulatory events, and that transitory elevations of progesterone concentrations may have specific short-term roles.
		These cyclical changes in the concentrations of steroid hormones observed in captive elasmobranchs support observations of hormone concentrations during reproduction in wild carcharhinids.
	www.publish.csiro.au /nid/126/paper/MF9920273.htm (356 words)

	First Record of the Ragged-tooth Shark, Odontaspis ferox, off the U.S. Atlantic Coast Marine Fisheries Review - Find ...
		The specimen was tentatively identified as a ragged-tooth shark based on the presence of teeth mostly with two or three cusplets on each side of cusp, unique to this species (Compagno, 1984).
		Odontaspids are also characterized by lanceolate teeth and the lack of nictitating lower eyelids, which differentiates them from similar families such as the scyliorhinids (cat sharks) and carcharhinids (requiem sharks) (Bass et al., 1975).
		Three rows of small intermediate teeth between the upper anterior and lateral tooth rows also indicated that the shark was O. ferox (Bigelow and Schroeder, 1948).
	www.findarticles.com /p/articles/mi_m3089/is_1_60/ai_54097810 (724 words)

	shark.html (Site not responding. Last check: 2007-10-13)
		It had been thought that all the hammerheads evolved from a single carcharhinid ancestor with a "normal-shaped" head.
		Geneticist Andrew Martin used mtDNA sequence data to explore the origins and pattern of hammer development in seven species (including two sub-species) of hammerhead shark.
		The data strongly shows that the Winghead Shark, not the Bonnethead, was the first hammerhead to diverge from the group's common ancestor and that the bonnethead was the most recent hammerhead to appear.
	www.gwtc.net /~eeemery/shark.html (491 words)

	The Oceanic Whitetip
		The whitetip has a short blunt snout, and its powerful jaws are filled with sharp serrated teeth.
		As in many other carcharhinids (members of the family Carcharhinidae), the shape of the teeth in the oceanic whitetip differ in the upper and lower jaws.
		In the upper jaw, the teeth are broad, triangular and completely serrated, but the teeth in the lower jaw are much more pointed (and not so broad and triangular), and only have serrations on a small portion nearer to the tip (Compagno, 1984).
	web.ncf.ca /bz050/whitetip.html (1729 words)

	IUCN Red List of Threatened Species: Carcharhinus macloti
		Although of small size, its life history may not be as productive as that of other small carcharhinids (e.g., Rhizoprionodon spp.), making it more susceptible to fishing pressure.
		It is assessed as Near Threatened because continuing fishing pressure may reduce the population to a level where it may meet the criteria for Vulnerable.
		A small species of carcharhinid sharks that is born at a relatively large size (45 cm), matures at 70 – 75 cm, and reaches a maximum of 110 cm (Last and Stevens 1994).
	www.iucnredlist.org /search/details.php/41737/all (602 words)

	Shark Gallery - Great White Shark taxonomy
		This species was originally described by Linnaeus (1758) as Squalus carcharias, with a type locality given as 'European Seas', essentially the Mediterranean.
		Considerable confusion between Linnaeus' S. carcharias and various Mediterranean carcharhinids (requiem sharks), and especially the sandbar shark Carcharhinus plumbeus, gave rise to some misrepresentative species accounts by European writers until the 1900's.
		Andrew Smith's nomination (in Müller and Henle, 1838) of Carcharodon for the white shark genus largely eradicated future confusion in nomenclature.
	gerber.iwarp.com /gwtax.htm (130 words)

	Feature Shark - Tiger (Galeocerdo cuvier)
		Tiger sharks have been aged using two methods: bands on vertebral centra and tag/recapture data.
		Overall, the tiger shark is similar to other large carcharhinids in that it grows slowly and is relatively long-lived.
		Tag data indicate that tigers grow fast in their first few years, increasing by 74% from their size at birth during their first year of life (see figure).
	na.nefsc.noaa.gov /sharks/newsletter/98/tiger.html (1334 words)

	Electroreception in juvenile scalloped hammerhead and sandbar sharks -- Kajiura and Holland 205 (23): 3609 -- Journal ...
		fields than carcharhinid sharks, this prediction was not supported
		a carcharhinid shark, with an electroreceptor distribution that
		Head morphology and electrosensory pore distribution of carcharhinid and sphyrnid sharks.
	jeb.biologists.org /cgi/content/full/205/23/3609 (6916 words)

	Shark Gallery - Sharks in general, Classification
		Unlike other animals, sharks have changed very little since.
		The most recently-evolved families of sharks are the sphyrnids (hammerhead sharks) and the carcharhinids (requiem sharks).
		One extinct shark known today from its enormous fossil teeth, Carcharodon megalodon lived in the Tertiary period, 1 0 to 70 million years ago.
	gerber.iwarp.com /descript/classification.html (347 words)

	Research Groups at NEAq
		Location : Home : Science : Research :
		In collaboration with the MA Division of Marine Fisheries (Dr. Greg Skomal) and using NOAA’s Apex Predator surveys as a platform, this work assesses the species-specific physiological status of coastal carcharhinids captured by bottom longline gear.
		Identifying differences in the physiological status (and resultant post-capture mortality) between these species is very important for management purposes.
	www.neaq.org /scilearn/research/subpage.php?id=42 (132 words)

	Table of Contents and Excerpt, McEachran and Fechhelm, Fishes of the Gulf of Mexico, Vol. 1
		The phylogenetic ranking and sequencing largely follow Nelson (1994), with several exceptions.
		Sphyrnidae are considered a family separate from Carcharhinidae despite the fact that carcharhinids are not monophyletic without inclusion of sphyrnids (Nelson 1994).
		The reason for maintaining this more traditional albeit nonmonophyletic classification is that the interrelationships within carcharhinids are poorly known and the sister group of the sphyrnids is not entirely clear.
	www.utexas.edu /utpress/excerpts/exmcefis.html (8979 words)

	IUCN Red List of Threatened Species: Carcharhinus falciformis
		Reproductive capacity limited (annual rate of population increase estimated as 4%).
		Despite a lack of population sizes estimates, observations of trends, or indices of abundance for any stock (studies of fisheries impacts are a high priority), the silky shark is considered to be susceptible to over-exploitation by analogy with better known carcharhinids.
		An oceanic and coastal species found in tropical waters around the globe.
	www.iucnredlist.org /search/details.php/39370/all (407 words)

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