Shark EvolutionMathieu Noe

Shark EvolutionThough sharks often only leave teeth behind this has been

enough to have a fairly detailed fossil record

There are between 2,000 and 3,000 species of fossil sharks

Shark Teeth Shark teeth are mineralogicaly stable

Shark teeth provide a number of characteristics with which to identify a species

Erosion and malformities

Earliest sharks The oldest fossils are scales 455 million years ago

The oldest true shark scales come from 420 million years ago

Devonian era was when shark became truly abundant

Ancient sharks There are important diferences between ancient sharks and

modern sharks (Cladoselache)

Short rounded snout with mouth in front

Tail with both lobes the same size

Naked

Early Modern Sharks Hybodonts

Mcmurdodus

Paleospinax

Neoselachians100 million years ago

Expansion of ray fined fishes

Expansion of higher teleost

Predominantly near shore predators

Expanded to a variety of different habitats

Modern Sharks Cow and frilled sharks

Batoids

Filter feeders

Hammerheads

Laminoid sharks Heavy built teeth

Lots of similar teeth

Future for sharks Future challenges for the survival of sharks

Adaptations to climate change