The early appearance of sharks can be attributed to the aquatic environment of the Devonian seas. Water, despite its penchant for chaos and turbulence, provided a stable medium for life due to ...

The Devonian ancestors of fishes living today belonged to two main nonarmored groups. The cartilaginous fish, so-called because cartilage formed their skeletons, later gave rise to sharks and rays.

It was also around this time that the first plants invaded the land. The earliest shark-like teeth we have come from an Early Devonian (410-million-year-old) fossil belonging to an ancient fish called ...

researchers believe it retained many larval traits and was likely a distant relative of modern sharks. “Discovery of the mysterious animal Palaeospondylus in the Early Devonian of Australia ...