The Dinosaur Age began in Tanzania and Zambia, following a tumultuous species shuffle in the aftermath of a mass-extinction event 252.3m years ago, new fossil discoveries have suggested. 90-percent of all life on Earth was wiped out, a new study published in the Proceedings of the National Academy of Sciences reports, with it taking around 10m years before the precursors of dinosaurs as we know of them began to emerge.
One such example was silesaurs, small herbivores more akin in size to a dog than the "terrible lizards" of Jurassic Park, but actually closely related to dinosaurs. Most common among silesaur fossil remains is the Asilisaurus kongwe, study co-author Kennet Angielczyk told Discovery, but in fact it's another of the same species that provides the most likely link with what came after them.
That animal is in face Nyasasaurus parringtoni, again similar in size to a large dog, but with an extended tail that fossils suggest was around 5-feet in length. "Nyasasaurus is either the oldest known dinosaur or the closest known relative of dinosaurs," Angielczyk says, "but we can't completely rule out either option because the material is rather fragmentary."
Angielcyzk and his team gathered fossil evidence in seven trips, with the bone fragments spread across Tanzania, Zambia, and Antarctica. However, while the fossils have allowed a greater insight into how dinosaur species developed, the actual nature of the mass-extinction event itself remains unclear.
One possibility is that an extreme form of global warming caused a mass species reduction - believed to involve an 80-percent decrease in four-legged species found in the majority of the areas studied - though other possibilities include volcanic activity or a meteorite strike.
Significantly shifting geographies means that the spread of early dinosaurs is made even more complex, but researchers on the team argue that the most important aspect of the discovery might instead be a cautionary tale for humans today. Should a similarly colossal mass-extinction event take place now, evidence of species development suggests it could take anywhere from 8m years for animal life to begin to recover.