Shark Fossils found in Florida
Text and illustrations are provide by Shark Teeth R Us at www.sharkteethrus.com.
   
Reef-Dwelling (or Requiem) - (upper jaw) -  The crown is fully serrated and can be either straight or angled.  As with most sharks, the teeth positioned closer to the back of the jaw tend to be shorter and more angled.  Common Requiem species include the Black Tip, Bull, Dusky, Reef, Sand Bar, Silky, Spinner and more.  (average size = 3/4 inch) - (scientific name Carcharhinus sp.)
Reef-Dwelling (or Requiem) - (lower jaw) -  Many Requiem species have lower teeth that look similar to their upper teeth (illustrated above).  The Bull and others will have lower teeth that look like this one (illustrated left).  The crown is either finely serrated (Bull) or not at all and can be angled.  (average size = 3/4 inch) - (scientific name Carcharhinus sp.)

Lemon -  The crown is not serrated.  There is a wavy cutting surface along the root, where the crown and root meet.  As with most sharks, the teeth positioned closer to the back of the jaw tend to be shorter and more angled.  (average size = 3/4 inch) - (Lemon scientific name Negaprion brevirostis)
Tiger -  The crown is serrated, including dramatic serrations near the root (on the inside angle of the crown).  Teeth near the back of the jaw can be much shorter.  (average size = 1 inch) - (scientific name Galeocerdo cuvier)  An extinct Tiger species has a more dagger-like crown and less dramatic serrations.  (average size = 3/4 inch) - (scientific name Galeocerdo contortus)
Sand Tiger -  The long, slender crown is not serrated.  There is a single cusp on each side of the crown, which is often damaged.  Note the U-shaped root, which is also prone to damage.  (average size = 1 inch) - (scientific name Odontaspis taurus)  A similar looking tooth has a less "U" shaped root and is slightly wider where the root and crown meet.  It is an extinct Sand shark species.  (average size = 1 inch) - (scientific name Odontaspis cuspidata)
Snaggletooth (or Snaggle-Toothed) -  The crown has dramatic serrations.  Upper teeth are fully serrated and can be either wide or narrow.  Lower teeth are generally narrower and are not fully serrated.  They become less serrated as they approach the front of the jaw (remaining serrations near the root).  Both upper and lower teeth have a “median boss“ protruding forward in the center of the root, on the display side.  (average size = 1 1/4 inch) - (scientific name Hemipristis serra)
Extinct Mako? -  This tooth looks very much like the Great White, but the crown is not serrated.  The crown can be angled, but not dramatically.  (average size = 1 1/2 inches) - (scientific name Isurus hastalis)  This was once assumed to be an extinct Mako species (and is often called Mako or extinct Mako), but is more likely an ancestor of the Great White.  Modern Mako teeth are much narrower.
Megalodon (or Meg) -  The crown is serrated and can be slightly angled.  There is a “chevron” or "bourlette" below the root, on the display side of the tooth (the area above the dashed line), which is a different surface texture from either the root or the enamel crown.  (average size = 2 1/2 inches)  (largest ever found - over 7 inches) - (scientific name Carcharocles megalodon or Carcharodon megalodon.

Great White (or White Pointer) (or White Death) -  This tooth looks a lot like an Isurus hastalis tooth, but has heavy serrations.  It is rarely found in Florida.  (average size = 1 1/4 inches) - (scientific name Carcharodon carcharias)
The fossil shark teeth identified on this page are listed in the approximate order of their rarity (as found in Florida rivers).  The top listings are the most common and the lower listings are more rare.  This may help you decide what type of tooth you have found.  Chances are, if you are debating between two possible identifications, it's the one listed higher in the above chart.