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Fossil Shark Gallery
Tiger Shark Collecting Location:PCS Mine, Aurora, NC
Tiger Shark Collecting Location:Calvert CLiffs, MD
Parts of Sharks that Fossilize
Shark Evolution
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Tiger Shark Facts and Information - All about the Galeocerdo Tiger Sharks
History, Evolution, Fossil Teeth Identification, Fossil Examples, Fossil Hunting Locations, and more!
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GALEOCERDO (Muller and Henle, 1838)
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PHYSOGALEUS (Cappetta, 1980)
The Tiger Sharks
| Shark Info | Tooth Morphology | Contortus Composite Dentition | Bite Pathologies | Fossil Examples |
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Fossil Tiger Shark Information
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The Tiger shark, Galeocerdo genus, made its first appearance in the Eocene as G. latidens. G. latidens was a smaller Tiger shark with a proportionately wider root than other Tiger species. By the Oligocene, G. aduncus became the main tiger shark. This species became extinct in the late Miocene. It is replaced by G. cuvier in the Pliocene. G. cuvier is now the only extant Tiger species.
Physogaleus
P. contortus aka G. contortus, although similar looking to the tiger sharks, it is probably not related to the Galeocerdo genus. Although the teeth have a similar shape, the design is different. Galeocerdo teeth have serrations enabling a cutting design. P. contortus teeth have slender, twisted crowns with very fine serrations. This shape is better suited for grasping, not cutting. As a result, P. contortus would have probably had a diet of a diet of small bony fish and rays. The Physogaleus genus first appeared in the Eocene as a small shark called P. secundus. This genus continued to evolve into the Oligocene, and finally into the Miocene, where it became extinct. The last species of this genus is P. contortus. It is a short lived species that appeared in the late Oligocene and became extinct in the late Miocene.
Galeocerdo cuvier
G. cuvier, Modern Tiger sharks, are among the largest sharks; lengths of 3.35 m - 4.25 m (11 - 14 ft) are common, while the largest specimens are believed to exceed 5.5 m (18 ft) (Castro, p.125). Because Tiger sharks have a unique Tiger stripe pattern, they are easy to identify and often referred to as the spotted shark or leopard shark. As pups, they have dark spots along their dorsal surface, which fuse into vertical bars or stripes at maturity. These unique stripes begin to fade as the shark ages (Castro, p.125). Tiger sharks also have very short, blunt snouts. These characteristics make it very difficult to misidentify a Tiger shark.
Tiger sharks are found in all subtropical and warm temperate seas (Compagno, p.283). They prefer coastal areas, and are commonly found in river estuaries and harbors. In North America, they are found from Massachusetts down to the Gulf of Mexico and the Caribbean. On the Pacific side, they are found in Hawaii, and southward from Southern California. They are also known to seasonally migrate, moving from temperate to tropical waters in the winter; they also make long migrations between islands in the Pacific.
Tiger sharks are solitary nocturnal hunters and feeders. They will eat just about anything! Their diets include bony fishes, sharks, rays, porpoises, turtles, crabs, squid, birds, and even garbage (Castro, p.126). Tiger sharks are also known to prey on humans. They are second only to the Great White Shark in number of reported attacks on humans. However, please remember, a shark attack is a very rare event; normally these creatures will stay away from humans.
This shark has very little commercial value other than its jaws in souvenir shops. Some countries, however, use the shark for its fins. It is also classified as a game fish and loved by sports fisherman. The International Union for Conservation of Nature and Natural Resources (IUCN) has the Tiger shark listed as lower risk / near threatened.
Fossil Tiger Shark Tooth Morphology/ Identification
Galeocerdo cuvier is the extant Tiger shark. These teeth are unmistakable. G. cuvier teeth are the largest of all species of Tiger shark, and are very robust looking. They have an average length of approximately 2.9 cm (1.1") and an average height of approximately 2.2 cm (.86") (Purdy et al, p.149). Tiger teeth have complex serrations on their mesial cutting edges, and serrated distal cutting edges that are strongly notched. These teeth are ideal for a cutting dentition. The roots of Tiger teeth are flattened with square-like root lobes (Cocke, p.60).
While sharks of the carcharhinid family generally have upper teeth that are designed to cut and lower teeth that are designed to grasp, Tiger sharks have rows of almost identical teeth in both their upper and lower jaws. This creates a nightmare for the average fossil collector trying to identify upper teeth from lower teeth. Purdy et al identifies very slight differences in Tiger shark upper and lower teeth. In lower teeth, the tips of the crowns usually have a slight lingual bend, lower teeth have a slightly developed Taurus on the root, and the arch formed by the lower root is often asymmetrical (Purdy et al p.149). For upper teeth, they can have a noticeable labial curvature, and the arch formed by the lower root is usually more symmetrical (Purdy et al p.149). You may have noticed the use of words such as “usually," “can," and “often," this means not all teeth exhibit these characteristics. If you try and separate your uppers from lowers, good luck! I have been unsuccessful at separating most of my Tiger shark teeth.
Below is a diagram of a G. cuvier tooth.
Galeocerdo cuvier tooth from Aurora, NC
Galeocerdo aduncus is and extinct species that appeared in the Oligocene and became extinct in the late Miocene. This species of Tiger shark probably looked like a miniature, but less robust version of G. cuvier. Below is a diagram of a G. aduncus tooth.
Galeocerdo aduncus tooth from Aurora, NC
Physogaleus contortus aka Galeocero contortus is an extinct Tiger-like shark that, as with G. aduncus, appeared in the Oligocene and became extinct in the late Miocene. This shark had a very different tooth form. They are similar in size to G. aduncus, but have thicker roots. Their crowns are, however, slender and twisted; ideal for a grasping dentition. Below is a diagram of a P. contortus tooth.
Physogaleus contortus tooth from the Calvert Cliffs of MD
The Dentition
The following image is my composite dentition of P. contortus from countless teeth collected along the Calvert Cliffs of Maryland. It was reconstructed based on a picture of a composite dentition from the Lee Creek III book (Purdy et al, p.147).
Fossil Tooth Bite/Feeding Pathologies
A few collected contortus teeth have the mesial cutting edges completely sheared off. This type of feeding damage is very easy to recognize. The following image shows three teeth with this specific damage.When studying the morphology of tiger teeth, a probable reason emerges. Since the interior angle between the root base and the mesial cutting edge is acute, any excessive stress, such as biting into bone, would channel enough force to easily sheer off the mesial cutting edge. This type of feeding damage can also be seen in Hemepristis teeth, which have a similar acute interior angle.
P. contortus teeth that have their mesial cutting edges sheered off. The left two are from the Calvert Cliffs of MD, and the right one is from Aurora, NC.
Examples of Tiger Shark Fossils
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G. Cuvier, G. aduncus, P. contortus
(Tiger Shark) |
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Galeocerdo cuvier (Peron and LeSueur, 1822)
Tiger Shark This is the extant Tiger Shark. They obtained larger sizes than the other Tiger species. This fossil first appears in the Pliocene, such as the Yorktown Formation in Aurora. |
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The first left two are either symphysial or parasymphysial teeth. The right two teeth are posteriors. Formation:Yorktown Age:Roughly 2.5-5 m.y. Location:PCS Mine, Aurora, NC Size: largest one has a ~1 1/4" slant (32mm) |
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Formation:Yorktown Age:Roughly 2.5-5 m.y. Location:PCS Mine, Aurora, NC Size: largest one has a ~1 1/4" slant (32mm) |
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Formation:?Reworked from Yorktown? Age:Pliocene ~2.5-5 m.y. Location:Green Mill Run, NC Size: 3/4" (~19mm) Date:Oct 2006 Trip |
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Galeocerdo aduncus(Agassiz, 1843)
Extinct Tiger Shark This species lived from the Oligocene into the Miocene. This extinct species is much smaller and less robust looking than the extant (living) Tiger shark (G. cuvier). These teeth are abundant in the Pungo River Formation at Aurora, NC and the Miocene Calvert formation in MD and VA. |
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Formation: Age: Location: Size: |
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Notice the coarse serrations on the enameloid shoulders. Uppers and lowers are very difficult to tell apart, these are arranged in no particular order. Age: Location: Size: |
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Age: Location: Size: Date:: |
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Physogaleus contortus aka Galeocero contortus
Extinct Tiger-like Shark Purdy et al (2001). This species of Tiger Shark is very common along the U.S. East Coast deposits, but rarely found along the U.S. West Coast deposits. This species Lived from the upper Oligocene and became extinct in the Miocene. There are a few big differences between these and G. aduncus. First, the crowns are twisted, looking pathological, as shown in the profile view. Also, the enameloid shoulder has very fine serrations, unlike the coarse serrations of G. aduncus. This slender tooth form probably means the contortus fed on bony fish, while the aduncus and extant cuvier species fed on a wider variety of prey. This extinct species is also smaller than the extant (living) Tiger shark (G. cuvier). |
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Formation:Pungo River Age:Roughly 18-22 m.y. Location:PCS Mine, Aurora, NC Size: largest one has a ~ 7/8" slant (22mm) |
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The roots on lower contortus teeth are more robust than the roots on uppers. However, laterals and anterio-laterals are very difficult to tell apart. Age: Location: Size: |
