Strewn Dinosaur Species and Continental Drift

It is a fairly well-known concept today that continental drift is responsible for the seven separate continents we have today on Earth (schools of perception vary—some claiming the existence of six or even five continents today; however, this is beside today’s topic). 

It is also fairly well-known that much of the theory behind the existence of prehistoric animal species relies on theories of continental drift.  It is a bigger challenge however, to help some people cross the gap of belief when it comes to dinosaurs, and so each new discovery is important to witness and study in order that our own such advanced species be better prepared—if possible—for our own future on Earth.

A recent article in the Charlotte Observer highlights just one important discovery—recently made and concerning the separate remains of two dinosaurs of the same species and within the same time period and epoch, 1000 miles apart—in Utah’s Wahweap Formation and the Campanian Two Medicine Formation in Montana.

The article covers the type species Acristavus gagslarsoni, a genus of hadrosaurine dinosaur.  What is significant is that—unlike most other (but one) genus species– A. gagslarsoni lacked the trademark ornamentation on its skull usually associated with hadrosaurine dinosaur. ..but why?

Continental Drift and Dinosaur Evolution

Mountainous eruption, changes in sea level, land bridges…all of these phenomenon had immense impact on the adaptations and survival of prehistoric animals such as the dinosaur.  Approximately 79 million years ago, mountains of the Laramide range of the Rocky Mountains were raised in the Laramide orogeny.  (Oregeny is the term used to describe the forces and events leading to severe structural deformation of the Earth’s crust and upper mantle. These are forces that occur due to the movement and engagement of tectonic plates. Response to this engagement results in the formation of long tracts of highly deformed rock—eventually, they become the mountainous mounds of rocks known as The Rockies, the Sierra Nevada or the Sierra Madres…just a few examples. )

As the new orogenic belts erupted east to west across the narrow Laramide strip, they created fragmented dinosaur habitats which were once one.   Before this, Laramidia was a prehistoric island that stretched more than 1,200 miles, from today’s Canada all the way south, down to today’s Mexico.  At one time long ago, before the mountainous eruptions that would split regions, sauropod dinosauars roamed uninhibited from north to south and back again—utilizing the entire stretch of land in genus groups of species herds.

The Significance of Dinosaur Detours Caused By Continental Drift

It is exactly these kinds of “dinosaur detours” that propagate change among genus type species, and sometimes bring about such change too quickly and can affect species endangerment due to species isolation or other change.  However, as these changes occur quite naturally—over millions of years—endangerment doesn’t have to be a problem of genus, as individual species are able to biologically endeavor to adaptation.  Adaptation is ultimately responsible for (through the allowance of) evolution itself.

After studying the fossil records, it is believed that hadrosaurs (duck-bills) developed crests and horns that varied from habitat to habitat in order to help identify each other’s species origin and encourage recognition of the same species for mating.  Most scientists believe that the hadrosaur was a traveler anyway, and moved in large herds for long distances.  When new mountains eventually inhibited the usual travel of the genus, they were restricted in ways that they weren’t before.  Lack of food and increase of predation by the new Theropod dinosaurs ultimately meant trouble for the hadrosaur.

Add to this the drift of continents into new temperate regions, with permanent (lasting millions of years) adjustments to required ambient temperatures for various animal species.  Again, these kind of changes take place naturally over long periods of time.  Where some species and an entire genus may die out, there are others somewhat similar to take their place.  It’s still understood that in order for mass extinctions to occur, there had to have been major events – like continental drift – take place that would impact many species in a relatively short amount of time.