A third of dinosaur species never even existed?

A few paleontologists are spinning a theory that is as interesting as it is controversial. They’re claiming that up to a third of currently known dinosaurs species may actually have been misclassified, and that they may actually simply be juveniles, who undergo extensive physiological changes during their maturing into adulthood.

Instead, like birds and some other living animals, the juveniles went through dramatic physical changes during adulthood.

This means many fossils of young dinosaurs, including T. rex relatives, have been misidentified as unique species, the researchers argue.

How T. Rex Became a Terror

The lean and graceful Nanotyrannus is one strong example. Thought to be a smaller relative of T. rex, the supposed species is now considered by many experts to be based on a misidentified fossil of a juvenile T. rex.

The purported Nanotyrannus fossils have the look of a teenage T. rex, Horner said in the new documentary. That's because T. rex's skull changed dramatically as it grew, he said.

The skull morphed from an elongated shape to the more familiar, short snout and jaw, which could take in large quantities of food.

But the smoking gun, Horner said, was the discovery of a dinosaur between the size of an adult T. rex and Nanotyrannus.

Nanotyrannus—actually a young T. rex in Horner's view—had 17 lower-jaw teeth, and an adult T. rex had 12.

The midsize dinosaur had 14 lower-jaw teeth—suggesting that it was also a young T. rex, and that tyrannosaurs gradually traded their smaller, blade-like teeth for fewer bone-crushing grinders in adulthood.

Being a moderate dino-lover (hey, be frank, who didn’t love dinosaurs as a kid?), this is certainly a stunning and exciting prospect to me. What’s all the more intriguing about this new hypothesis is its sources, which are Mark Goodwin of the University of California, Berkeley, and most of all, paleontological “superstar” Jack Horner of Montana State University. You know, the guy who served as adviser for the Jurassic Park films and who spread the notion that the T-Rex was less of a ferocious hunter and more like an opportunistic scavenger, and so forth. He’s also the one who theorizes that it may be possible to genetically reverse the effects of millions of years of evolution on birds, dinosaurs’ closest living descendants, and to therefore artificially reconstruct a living dinosaur in a laboratory …

Oops, forgive me. My geekiness is getting carried away, there.

Anyway. This idea is obviously encountering some fierce opposition – it is rather radical, after all – but quite frankly, I view Jack Horner & co. as the top authority on such matters, and they’ve proven themselves to be reliable and right time and time again, so I’m definitely inclined to entertain the notion that we may have made a large-scale mistake until shown better.

Perhaps as an amusing sidenote: this is certain to get certain anti-evolutionists to rear their ignorant heads up at the idea of scientists screwing up their identification and classification of specimens of the same species at various developmental stages, but this criticism – like all others, naturally – is bogus.

• First and foremost, this is still a highly theoretical idea and is far from being accepted as correct, for now anyway. It’s quite simply an educated guess, until cemented as fact through more research and study.
• And second, we’re talking about paleontologists failing to recognize maturing members of the same species. I would like it if someone explained to me, perhaps as they would to a four-year-old, how that is of much relevance to the dodgy old “transitional fossils” argument, which is a falsehood in itself (seeing as there’re no such things as transitional fossils. Every fossil is a standalone individual; if anything, 99.9% of fossils in existence are “transitional”, as they have both predecessors and successors).

Whatever your view on this development may be, there is one thing everyone is in universal agreement with: this is neat.

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