Pliosaur tooth, giant marine reptile Troodon This large enrolled trilobite is

This large enrolled trilobite is from the Devonian of the Alnif region of Morocco

The density of specimens in the Aspidella beds suggests levels of benthic biomass in the Neoproterozoic that could rival those of modern marine communities

Stylemys was a dry land tortoise found in the Oreodont beds (Middle Oligocene) of the White River badlands of South Dakota and northwestern Nebraska

The body was covered with thick

The type species is M

Pliosaur tooth, giant marine reptile Troodon This large enrolled trilobite isPLIOSAURUS(pronounced PLY oh SAWR us) Pliosaurus (meaning "greater lizard") was a huge, short necked plesiosaur that lived during the middle to late Jurassic period. This carnivore was a flippered marine reptile (a pliosaur and a plesiosaur, but not a dinosaur) with many sharp teeth in large, powerful jaws resembling those of a crocodile; the teeth were three sided in cross section. It was 33 40 ft (10 12 m) long and the skull was 5 6. 6 ft (1. 5 2 m)