The sprawling-upright transition across mammal evolution, showing changes in posture and limb bone shape. The transition from sprawling (reptile-like) to more upright (parasagittal) posture and ...

Scanning the desert landscape of Mexico’s Baja Peninsula, few people would imagine what crawls beneath the surface. Bright pink, with rudimentary eyes and just two limbs, Mexican mole lizards (Bipes ...

An early relative of crocodiles spent its juvenile years walking on all fours, then stood up on two legs as an adult. Its arm and leg bones grew at different rates to enable this transition. “The ...