Reasons to Believe

Secrets of Tyrannosaurus Rex

Though horror movies and haunted houses give me nightmares (literally), this Halloween I’ve got a monster on the brain, namely that ancient bone-cruncher the Tyrannosaurus rex. First named and described in 1905, this toothy fellow is one of the best loved dinos as well as one of the most researched, thanks to a high number of fossil finds. Yet according to a recent Nature news feature by Brian Switek, T. rex “has kept some secrets.”

The article discusses four T. rex mysteries that paleontologists are currently striving to solve.

  1. Murky evolutionary origins: In the 1990s, paleontologists scrapped the decades-old view of T. rex’s evolutionary history, which pegged the giant predator “as a descendent of Allosaurus.” New research places T. rex in a family of tyrannosaurids, many of which were much smaller than their famous relative. Switek observes, “The question for palaeontologists is how tyrannosaurs rose to power from such humble beginnings.”
  2. Juvenile specimens—or different species: Debate abounds about whether a dinosaur known as Nanotyrannus lancensis may actually be a juvenile T. rex, rather than a distinct species, with researchers falling on both sides of the issue.
  3. Fuzz, feathers, or scales: Though Jurassic Park depicts T. rex (and other dinos) as scaly beasts, some researchers argue that T. rex may have been covered in fuzz or feathers. Fossils of other tyrannosaurs indicate that these creatures “had a coat of ‘dinofuzz’” while Yutyrannus huali was covered in plumage. Some researchers believe that the evolutionary link between these animals and T. rex could suggest that the latter also sported fuzz or feathers. However, other scientists point out that, as of yet, no actual T. rex fossil has shown signs of this coating.
  4. Stubby arms: Let’s be honest, many of us enjoy poking fun at T. rex’s ridiculously tiny arms—but we’d all stop laughing if we were staring a living specimen in the face. Scientists suggest T. rex’s odd appendages may have served such purposes as mating and courtship displays, gripping prey, and rising from a resting position.

So, where do these conundrums fit in the dialogue between evolutionary and creation models? From my layperson’s perspective, it seems that T. rex does not necessarily support evolution as solidly as some may believe. Indeed, a creation model may provide a more complete and robust explanation for the T. rex data.

I took this question to RTB biochemist Fazale Rana for his opinion. He pointed out that the issues in T. rex research are not unusual. Piecing together an accurate picture of life history is no easy feat. He explained,

Our understanding of life history as based on the fossil record is very fragmentary—more than people are led to believe. These models are easily overturned even though they’ve been around for decades and are, in some cases, orthodoxy. For example, we just did a Science News Flash on a fish fossil find that overturned the standard evolutionary story for the history of fish.

Fuz also pointed out that the term “transitional intermediate” (sometimes called “transitional forms”) is more ambiguous than many people may be aware. In one sense, transitional intermediates are a clear, traceable pathway from creature A to creature B. This is usually the definition that creation advocates refer to when they point out that there are no transitional forms to prove Darwinian evolution.

However, transitional intermediates can also refer to organisms that simply existed between creature A and creature B (such as the smaller, earlier tyrannosaurs), though without a clear pathway of evolution. Take hominids for example. Between the appearance of the first hominid (creature A) and modern humans (creature B) there existed a number of hominid species. There is no obvious pathway uniting all of these animals on a common family tree—yet they are often cited as evidence for human evolution. Fuz stated, “What’s not communicated is how speculative it is.”

T. rex’s case appears similar. There is speculation about how this monster arose via evolution, but the support for this view is not as strong as it is often portrayed to the general public. A creation model, on the other hand, easily explains the appearance of T. rex as the work of a Creator. And even if paleontologists do someday find the “missing links” in T. rex’s history, it’s still not unreasonable to interpret these creatures as the products of common design, rather than common descent.

As Fuz put it, “There are other legitimate interpretations of the data. The fossil record doesn’t negate evolution, but we can also account for fossils using a creation model perspective.”

That’s something to chew on along with the Milky Ways and Starbursts this Halloween.

— Maureen

Resources: Just for fun, here’s a collection of Halloween-themed posts from Take Two.

Subjects: Dinosaurs