Reptile predates dinosaurs by eons

Fossils of 240 million-year-old creature found in East Africa

By Amy Husser, Vancouver Sun, March 4, 2010, p. B4

A new “dinosaurlike” creature discovered recently in East Africa roamed the earth 10 million years earlier than its already ancient cousins, suggesting dinosaurs and their close relatives may have originated much earlier than previously believed.

The new specimen, known as Asilisaurus Kongwe—meaning ancient ancestor lizard—was a four-legged animal measuring one to three metres long and one-half to one metre high from the hips, with a beaklike lower jaw and triangular teeth. It weighed between nine and 30 kilograms.

It was likely an herbivore or omnivore, which may have offered an “evolutionary advantage” since ecosystems can support greater numbers of plant-eaters.

The fossils of at least 12 of these creatures were discovered in 2007 in Ruhuhu Valley of southern Tanzania, but the findings of the six-person team of researchers—including one Canadian—will be first published in this week’s edition of the journal Nature.

“If dinosaurs were equal to humans, then asilisaurus would be a chimp,” explained lead author Sterling Nesbitt. “So, it doesn’t share all of the features humans share, but it shares many, many of them.”

The researchers suggest the asilisaurus lived 240 million years ago—about 10 million years before the oldest known dinosaurs existed—placing its origin in the middle Triassic period instead of the upper Triassic, but still long before the subsequent Jurassic and Cretaceous periods, when dinosaurs ruled the earth before extinction.

“It definitely shows that there were lots of non-dinosaurian creatures that lived around the same time as the first dinosaurs,” said Linda Tsuji, a Mississauga, Ont., native who is completing a doctoral degree at Humboldt University in Berlin.

“It shows how diverse the world was at this time in terms of these kinds of reptiles,” she added. “It could have been that dinosaurs existed along with a whole bunch of other similar creatures or reptiles, but dinosaurs, in the end, became the dominant creatures in the upper Triassic [period] and into the Jurassic.”

Asilisaurus is part of a dinosaurlike sister group known as silesaurs, only first discovered in 2003, and the closest known relative to dinosaurs. Silesaurs and dinosaurs lived side by side during much of the Triassic period.

Nesbitt said tracing the lineage of the newly found creatures could potentially help to fill in some blanks in the family tree since the findings show some branches “outside of dinosauria” may have split off.