No fossil organisms have been identified as similar to the last common ancestor of arthropods; hence the eyes possessed by the first arthropod remains a matter of conjecture.

A variety of Cretaceous and Tertiary fossil organisms exist in abundance.

Biochrons are named after characteristic fossil organisms or taxa that characterise that interval in time.

It contains public exhibits representing almost every type of fossil organism.

The halkieriids are a group of fossil organisms from the Lower to Middle Cambrian.

Micropaleontology deals with all microscopic fossil organisms, regardless of the group to which they belong.

The Pan-Aves thus contain the living birds and all (fossil) organisms more closely related to birds than to crocodilians (their closest living relatives).

Aysheaia was a genus of Cambrian-aged soft-bodied, caterpillar-shaped fossil organisms with average body lengths of 1-6 cm.

As it turns out, counting up what different kinds of fossil organisms lived in any particular time period is not as simple as it may sound.

More than 3,300 different kinds of fossil organisms have been found in the state.