Mongolepis (Mongolian scale).
Classification: Chordata, Chondrichthyes, Elasmobranchii.
Diet: Uncertain, presumed carnivore.
Size: Uncertain due to lack of fossil material.
Known locations: Mongolia.
Time period: Late Silurian.
Fossil representation: Placoid scales.
Mongolepis is one of the earliest known sharks and its scales date back to four hundred and twenty million years ago. Two other sharks named Elegestolepis and Polymerolepis are also known this time period, and are also only known from their scales. This means that while science accepts these as being representative of sharks, no one knows what they exactly looked like.