Category Archives: Shark Teeth Fossils

Lemon Shark and Sand Tiger Shark Teeth; Identification and Interesting Facts

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Lemon Shark

Lemon Shark (Negaprion brevirostris) Fossil Teeth (3/4 inch (1.9 cm) long)

Lemon Shark, Negaprion brevirostris, first appeared in the fossil record approximately 50 millions-years-ago beginning in the Eocene Epoch and are still here today, but are nearing the threatened list!

Named for their yellowish-brown color, which helps to disguise the fish over a yellowish-gray seabed, Lemon Sharks prefers coastal waters, lagoons or mangroves, typically staying close to the water surface. Even though humans reside in these areas, they are of little threat.

They are a large, heavy shark with an average length around 10 feet (3 meters). The shark has a flattened head with a short, broad snout. Three of their triangular dorsal fins are approximately the same size and shape, which is unusual compared to other sharks.

Lemon sharks are commonly found along the Southeastern Coasts of the United States and the Gulf of Mexico, but can also be found throughout the Caribbean and Southern Brazil. They have also been known to migrate to places as far east as West Africa.

Lemon Shark teeth have fairly large roots which are near straight across the top. The blades are smooth and narrow coming to a sharp point and typically grow out from the root at a 90 degree angle.

They can live to near 30 years.

Sand Tiger Shark

Sand Tiger Shark, Carcharia taurus, first appeared in the fossil record during the late Cretaceous Period, around 72 million-years-ago, replacing their predecessor, the extinct Sand Tiger shark, Carcharias cuspidatus, which appeared more than 45 million years earlier. Like the Lemon Shark, they are also threatened.

Sand Tiger sharks inhabit coastal sandy shorelines (hence the name sand tiger shark). They also inhabit shallow bars, estuaries and tropical reefs to a depth of around 627 feet (191 meters). Even though they roam the surf in close proximity to humans, they are of little threat. They are normally quite docile, plus their mouths are not large enough to cause a human fatality.

Sand Tiger sharks dwell in waters off the east coasts of North and South America, Japan, Australia, Africa, and parts of the Mediterranean. Because they have a worldwide distribution, they have inherited several common names, including; grey nurse shark, spotted ragged-tooth shark or blue-nurse sand tiger. The term “sand tiger shark” actually refers to four different Sand Tiger shark species in the family, Odontaspididae.

Sand Tiger Shark (Carcharias taurus) Fossil Teeth – 2 Upper and 1 Side (Longest sample is 1 inch (2.5 cm) long)

Sand Tiger shark, Carcharia taurus, are large and bulky reaching up to approximately 10 feet (3 meters) in length. The head is pointy, while the snout is flattened and the mouth extends beyond the eyes. The Sand Tiger has a light grey-brownish back and pale underside. Adults tend to have reddish-brown scattered spots, mostly on the hind part of the body.

The Sand Tiger usually swims with an opened mouth displaying three rows of protruding, smooth-edged, sharp-pointed teeth that have side cuplets, which once removed from the mouth, may or may not later become worn off. The upper front teeth are separated from the side teeth by small intermediate teeth. The roots are deeply curvaceous.

Sand Tiger sharks can live up to 40 years.

Other Shark Facts

  • Sharks are covered in scales called dermal denticles, which are covered with a layer of enamel, like our teeth. The denticles protect the shark’s skin from injury. They also help water glide over the shark as it swims so it can move quickly and quietly through the ocean.
  • Sharks need to keep moving in order to pass water through their gills to receive oxygen.
  • The dark color over their topside helps to camouflage them from above while the light color on their bottom side blends with the sunlight to fool their prey below.
  • Sharks have electro sensors to help them navigate and find prey, compensating for their poor eyesight.
  • Sharks lack bones, their bodies are mostly made up of flexible cartilage which is lighter than bone requiring less energy for them to stay afloat.
  • Sharks loose and replace their teeth on a regular basis.


Factors Contributing to Population Declines of Sand Tiger and Lemon Sharks

  • Over fishing, particularly, by eastern countries such as China and Japan
  • Pollution in estuaries where pups are bred
  • Competition with humans for food
  • Exploitive Fishing Nets

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Two Extinct Sharks: Snaggle Tooth and Otodus, Obliquus

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Snaggle Tooth Shark (Hemipristis, serra) Fossil Tooth (1.25 inch (3 cm) long and wide)

Snaggle Tooth Shark

It may seem obvious, but the Snaggle Tooth Shark inherited its name from the large serrated edges running along the crowns of its teeth. Hemipristis, serra is an extinct species whose fossil teeth are found worldwide. In 2014, a family in Chesapeake Bay, Maryland found an extremely rare fossilized skeleton of a 15-million-year-old, H. serra shark. The cartilage skeleton is the first one of this species ever found.

This breed could reach an estimated length of 20 feet (6 meters), equivalent to the largest Great White Sharks of today. A tropical breed, they lived beginning from the Oligocene Epoch (around 30 million-years-ago) through the Miocene Epoch and into the early Pleistocene Epoch (about 1mya) before dying out, likely due to earth’s cooling temperatures. Their fossilized teeth are highly prized by collectors.

Extinct Snaggle Tooth Shark (Hemipristis, serra) Rendition Drawing

Classification Snaggle Tooth Shark

Class: Chondrichthyes (Cartilage Fishes)

Superorder: Selachimorpha (Cartilage Skeleton with five to seven gill slits on the sides of the head and pectoral fins that are not fused to the head.)

Order: Carcharhiniformes (Ground Sharks with nictitating membrane over the eye, two dorsal fins, an anal fin and five gill slits.)

Family: Hemigaleidae (Weasel sharks, ground sharks found in eastern Atlantic Ocean to the continental Indo-Pacific in shallow coastal waters to a depth of 100 meters (330 feet).

Genus: Hemipristis (Snaggle Tooth)

Species: serra (Extinct specie)

Otodus, obliquus Shark

Extinct Otodus, obliquus Shark Tooth Fossil (1.25 inch (3cm) long, 1 inch (2.5 cm) wide)

Extinct mackerel shark, Otodus, obliquus, fossil teeth are found in the phosphate pits of the Atlas Mountains of Morocco and the Nanjemoy Formation in Maryland, USA. Thought to be one of the first giant sharks and top predator of its time, the shark ruled the ocean’s from the Paleocene Epoch about 66 (million-years-ago) to the Pliocene Epoch around 1.8 million-years-ago.

O. obliquus averaged approximately 30 feet (9 meters) long with the largest possible exceptions reaching up to 40 feet (12 meters) long. To put that in perspective, the Great White Sharks largest exceptions are 20 feet (6 meters) long. Their teeth are noted for their wide triangular crown and large side-cusps.

Otodus, obliquus Extinct Shark (Scale Rendition Drawing)

Classification Otodus, obliquus

Class: Chondrichthyes (Cartilage Fishes)

Order: Lamniformes (Possessing two dorsal fins, an anal fin, five gill slits, eyes without nictitating membranes, and a mouth extending behind the eyes. Commonly known as mackerel sharks; includes some of the most familiar species such as the Great White. Also, distinguished for maintaining a higher body temperature than the surrounding water.)

Family: Otodontidae (Extinct sharks described as mega-toothed sharks. It is believed to be an ancestor to Megalodon.)

Genus: Otodus (The teeth of this shark are large with triangular crowns, smooth cutting edges, and visible cusps on the roots. Some Otodus teeth also show signs of evolving serrations.)

Species: Obliquus (Extinct specie)

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Megalodon Vs. Great White Shark

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Megalodon Vs. Great White Shark Comparison Pencil Drawing

You can find plenty of information on the internet and in books about both of these fascinating creatures, but let’s face it, the magnitude of Megalodon’s girth is mind blowing, as you can see by the comparison drawing above. Keep in mind, these are not their average sizes, but their most exceptional sizes found in the fossil records.

Due to the multitude of unearthed shark teeth, scientists are able to determine size, species and age of these amazing creatures and the fact that the largest Megalodons were female, as with the Great Whites.

Sharks are important to all life on earth keeping the oceans clean of dead debris. Without them, our oceans would be overrun with bad bacteria killing all other ocean life which feed the world.

Great White Shark Tooth Front and Back (Lingual Side and Labial Side) 2 Inches (5 cm)Long

On average, Great White sharks have approximately 300 teeth, but lose dozens of them per month, which are readily replaced by several rows of backup teeth. In a single lifetime, these sharks can acquire over 20,000 teeth. This would explain why the average beachcomber can readily find volumes to add to their collections! Megalodon had almost as many teeth as the Great Whites, but when you figure in Megalodon’s approximately 20 million-year-timespan on Earth, compared to Great Whites approximate 6 million-year-timespan, it’s not surprising Meg teeth are equally as common to find, if not more.

Megalodon Carcharocles megalodon Shark Tooth Fossil
Comparing Shark Teeth Characteristics

In comparison, Megalodon shark teeth have larger, wider roots than the Great White sharks and typically display a medium to wide bourlette (chevron shaped space between the root and the crown of the tooth). Also, the Megalodon had small, regular spaced serrations along the edges, while the Great White shows thicker, irregular serrations.

Sometimes, the size of the tooth fossil is another way you may tell them apart, depending if the tooth is from a juvenile or an adult. The largest Megalodon tooth ever found is a little over 7 inches (18cm) long, filling a mans palm. The largest recorded Great White shark tooth is just over 3 inches (7.5cm) long.

Scale Pencil Drawing of Megalodon Jaw and Teeth

Where can you find Megalodon teeth?

Megalodon shark teeth have been found on every continent except Antarctica. And in the U.S., their teeth have been found in every state along the East Coast, especially Florida and the Carolinas. Their teeth have also been found in Texas, Louisiana, California, Washington, Hawaii, Michigan and some other Midwestern states. The best environments to find shark teeth are beaches, creek beds, dried riverbeds and abandoned dig sites.

Why did Megalodon become extinct?

Megalodon teeth fossils date from the early Miocene Epoch about 23 million-years-ago until the end of the Pliocene Epoch about 2.58 million-years-ago. Modern Great Whites evolved from the middle of the Miocene Epoch around 10 million-years-ago to the present. Consequently, the Great Whites lived toward the end of Megalodon’s tenure on Earth and scientists predict they competed with juvenile Megalodons for food. Also, changing ocean currents resulting in colder temperatures drove one of Megalodon’s essential prey of whales to colder climates, which Megalodon was not adapted to. A megaton creature needs megatons of food to survive and scientists predict the species was likely starved out of existence.

White Shark Fossil Tooth – 2 inches (5cm) Long

I originally thought the above shark teeth were from Megalodon, but have since determined they fit better from another breed of large white sharks, possibly, Carcharodon hastalis, an extinct known species found world-wide from marine deposits of the Miocene and Pliocene epochs, around 20 million to 3 million-years-ago. Their teeth are often found right along with the teeth of Megs and on average measure from 1-3 inches (2.5 – 7.5 cm) long, topping out at 4 inches (10 cm) long, second only to Megalodon. Roots of upper teeth are large, but not as broad in comparison, and the crowns lack the edge serrations and chevron shaped bourlette between the crown and roots distinguishable in Megalodon’s.

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