English to German Other Biology (-tech,-chem,micro-) Krokodile

Did you know that...?

...They evolved first.
They appeared as land animals -- with slightly longer legs and shorter snouts than those we know today -- approximately 200 million years ago, in the time of dinosaurs. Their fossils show that they evolved in different ways and began their semi-aquatic life with characteristics similar to mammals and birds, in contrast to that of other reptiles.

Es geht um Krokodile. Mir fehlt hier aber der rote Faden, warum es heißt "They evolved first", vielleicht im Sinne von: die ersten Reptilien, die sich entwickelt haben?