Tan

Trapdoor spider

Hidden door, lightning strike.

Ostracod

Tiny shells, huge history

Dimetrodon

Permian sailback-before dinosaurs

Eryops

Permian powerhouse of the ponds

Deinocheirus

The terrible-handed wetland omnivore

Quetzalcoatlus northropi

Largest skies, long-necked hunter

Allosaurus

Jurassic hunter of the Morrison

Lystrosaurus

The beaked survivor of Earth's worst crisis

Pachycephalosaurus

Built like a bipedal battering ram

Barylambda

Heavyweight of the Paleocene

Yellow Crazy Ant

Small ant, supercolony impact

Nutria

Orange teeth, big impact on wetlands

Orinoco Crocodile

Orinoco's long-snouted river giant

Onager

Iran's lightning-footed onager

Olingo

Neotropical night-fruit acrobats

Oribi

The grassland ghost on tiptoe

Kiang

Tough hooves for the Roof of the World

Vole

Small rodents, big ecosystem impact

Urial

Horns of the high dry hills

Aussiepom

Small body, big herder-brain.

Bullboxer

Powerful heart, playful paws.

Treehopper

Helmets on, vibrations on.

Agkistrodon Contortrix

Hourglass bands. Hidden hunter.

Savannah Monitor

West Africa's clawed ground-forager