Place in evolutionary scale
(365 million years ago)
This early tetrapod had a weight-bearing pelvic girdle, allowing it to shift propulsion from the front to hind limbs.
(375 million years ago)
Pelvic bone Evidence of "all-wheel drive" in a fish. The pelvis is comparable in scale to those of early tetrapods.
(385 million years ago)
Femur The lobe-finned fish, an early relative of tetrapods, had a pelvic girdle much smaller than the pectoral one, suggesting it had "front-wheel drive" propulsion.