Imagine a world where the boundaries between “fish” and “not-fish” blur, where the ancestors of birds and mammals once swam ...

The absence of a notochord, he says, is one factor that has allowed for the many interpretations of yunnanozoan phylogeny, and therefore he says it was “a little bit of a surprise” to see the fish ...

Can a single protein-encoding gene determine whether a vertebrate embryo develops normally ... who found that suppression of ...

Fossils found in the Burgess Shale of British Columbia show traces of a notochord (a rodlike primitive backbone), a significant step in the evolution of vertebrates. Cambrian sediments found in ...

No known living vertebrate has so miniscule a brain in ... In most creatures with backbones, vertebrae replace the notochord in the embryonic stage of development. But the coelacanth has no ...

When Schwann heard about the nucleus, he realized that he had seen a similar structure in the vertebrate notochord—a rodlike structure in the embryo that develops into the spinal column. Sure enough, ...

At anterior end, below the notochord, is the intercentrum ... Amphibians are the first vertebrates to have a neck, even if it is short & stout. Linked with this advance is a more flexible ...

Many four-legged animals go through embryonic stages that have similar features -- gill arches, a notochord, segmentation, and paddle-like limb buds -- as they develop into different adults.