From the Jurassic period (202 million years ago) to the tertiary period. These prehistoric sharks made an astounding eight evolutionary changes, pointing to the modern mako shark. The Isurus Desorii changed to suit its environment and the food available. These are classified as extremely rare fossils since there are so few of them being excavated. Isurus Desorii is the earliest known extinct mako giving rise to subsequent prehistoric sharks later in time. These fossilized teeth are excavated, Undug and cleaned with painstaking precision, a certificate of authenticity is then prepared giving it's age in approximate millions of years, continent of origin, period of existence, rarity and the precious metal (14kt gold or sterling silver) which you order your fossilized shark tooth pendant crafted in. Limited supplies available. These fossils come in three different sizes.