Belgian Fossil Sharks

Carcharodon carcharias, Pliocene, Doel (Left) and Hoevenen (right). Tallest, height 56 millimeters.

Belgian fossil Great White

Whatever some people may think, present-day Great White shark has not Megalodon shark for ancestor.

The latter should be actually extinct without descendants, but we can still not be fully sure of this.

Great White is the latest of a quite big gallery of ancestors during since Eocene period. (About 50 million years old)

As generally admitted, it’s Eocene ancestor has been Isurus praecursor, after appeared Macrorhizodus americanus we can find in upper Eocene sediments in the States and in Kazachstan.

At Oligocene period (about 30 million years old) we see this lineage splitted in two : one side is a fish-eating form having tall and thin teeth, called Isurus desori, the other side a meat-cutting form with wider and flatter teeth, called Isurus flandricus.

Miocene and lower Pliocene epoch see no real difference in shape for Isurus desori, we can only notice an increase in size of the teeth.

It is giving present day Mako sharks : Isurus oxyrhynchus and Isurus paucus.

Isurus flandricus leaved space to Cosmopolitodus hastalis, whose size progressively increases until end of Pliocene period where it disappears. Teeth may reach 8 centimeters or more in Belgian fossil sites like Kallo, Doel, Rumst and Sint-Niklaas. This species has teeth with sharp (non-serrated) cutting edge.

At upper Miocene and Pliocene periods, we encounter more and more an intermediate form with slightly serrated cutting edge, not very visible to the naked eye. We can feel serrations by walking a nail on the cutting edge. This species is called Carcharodon escheri.

Pliocene period sees emergence of real Great White, Carcharodon carcharias, whose cutting edge shows typical rough serrations. Present-day species still owns them. We encounter it not so frequently in lower Pliocene Belgian sediments, and quite more often in upper Pliocene sands.

Some teeth of Cosmopolitodus hastalis, Isurus desori and Carcharodon carcharias found in Antwerp Harbour area are displayed in the photo album « requins-fossiles » (“fossil sharks”) of my blog.

See you later !

Phil “Fossil”