Today's fossils and badlands of Arizona's Petrified Forest give the best view on Earth of a wet tropical world from the Triassic Period (~220 million years ago); a time and place where some of the very first dinosaurs walked beside much larger creatures in the shade of the Park's world-famous giant trees, which had not yet fallen and fossilized.

 

 

Petrified Forest National Park: new visions of the Triassic

The Park commissioned me to create a new life-sized wall mural to update its original museum displays of this ancient life, some of which dated back to the 1930's when much less was known of the local fossils and formations.

 

Giant salamander-like forms longer than a man, chunky and vicious croc-relatives on two legs, beaked yet rhino-like proto-mammals, and small, agile dinosaurs were just some of the strange cast of characters that breathed in this lost Triassic wilderness, which is today found only as many square miles of dusts, stone, and bones within the soft vibrant hills called the "Painted Desert."  And of course, littered throughout, are giant stony logs shaded in brilliant colors of gem-like minerals., fallen forests turned to stone.

Above:  from left, in a detail from the new Leshyk Mega-Mural, a small ground-running crocodylomorph (immediate crocodile ancestor) an aetosaur (Desmatosuchus), an early dinosaur (Coelophysis sp.), and a yet different aetosaur (Typothorax sp.) try to look busy for the camera.

The challenge of updating the Park's previous imagery required a reinvention of the anatomy, posture, appearance, and behavior now posited for the many fossil creatures found in the Park.  In my new work, the early dinosaur Coelophysis wears a trim coat of primitive pin-feathers in line with the new thinking that feathery insulation on warm-blooded theropods may have arisen very early in dinosaur evolution.  Scientists now recognize an early "side-group" to dinosaurs called dinosauromorphs, which ran alongside the earliest dinosaurs but went extinct before the great Age of Dinosaurs entered full swing.  In the new mural, the Park's dinosauromorphs are represented by swift quadrupedal Silesaurids which leap and scatter before a top predator like reptilian deer.  The bizarre, heavily-armored swimming reptile Vancleavea and a tree-dwelling chameleon-shaped drepanosaur also make their debut among the smaller illustrated fauna.

Key among the needed updates to the old views of the Petrified Forest was perhaps the most iconic feature to portray correctly; the trees which were themselves this National Park's namesake.  For years, the famous multicolored logs which tumble out from the Park's eroding hills had been reconstructed as tall naked poles with a dense crown of branches only at the top.  This lollipop / umbrella-shape was based on today's monkey-puzzle trees, as early researchers thought the petrified logs to be the ancient ancestors of the primitive Araucaria trees which today survive only in South America as holdovers from the Mesozoic.

 

Close study of the Park's petrified wood now shows that there is more than one type of fossil tree in the mix, but whatever they were, their full identities are not yet known as much of the wood is present only as fossil logs which were denuded of all branches, bark, and foliage when washed and bashed together down streams and rivers before getting buried in muds and sands.  However, knots and short branch stubs on these logs show that a major type of petrified trees were probably tall conifers that had many long slim branches from crown to base which probably bowed gracefully as they extended further away from the trunk.