The 300-million-year-old meat-eating Eocasea martini (full animal in this illustration) may have made it possible for larger plant-eaters such as Cotylorhynchus (illustrated footprint shown) to exist.
This three-dimensional reconstruction shows the skull of the sharklike Ozarcus mapesae. The braincase appears in light gray, the jaw in red, the gill arches in yellow and the horseshoe-shaped hyoid bone in blue.
A. Pradel, AMNH
NOW AND THEN A pupa of a modern leafcutter Megachile bee female (left) has the same basic look as a Megachile male (right, CT scan) that is at least 23,000 years old, having been preserved in the La Brea Tar Pits.