Third of Dinosaurs Might Not Have Existed

[GrnMarvl14]

Source.

(PhysOrg.com) -- A new ten-year study by US paleontologists suggests that up to a third of dinosaur fossils may have been incorrectly identified as new species, when they are actually juveniles of species in which there was a dramatic change as they developed.

Jack Horner, of Montana State University, said in a new documentary to be aired on the National Geographic channel, that one example was the Nanotyrannus, which was identified as a separate species but which may in fact be a juvenile Tyrannosaurus Rex, whose skull changed dramatically as it matured, becoming much less elongated. This was suggested after a dinosaur mid-way between the size of a Nanotyrannus and Tyrannosaurus Rex was discovered.

According to Horner, Nanotyrannus, which had 17 teeth in the lower jaw, was in fact a juvenile T. Rex, which had 12 lower-jaw teeth. The newly discovered dinosaur had 14 teeth in the lower jaw. Horner suggests that as the Tyrannosaurus Rex grew, it lost its small, blade-like teeth for larger bone-crushers.

The researchers also studied late Cretaceous fossils of Triceratops found in the Hell Creek formation in eastern Montana. These dinosaurs had died at various ages, and their fossils revealed a number of changes as the animals grew. The skulls revealed the juveniles' horns curved backwards, while the adults' horns pointed forwards, while the bones around the frill flattened and lengthened as the dinosaur matured.

Another researcher, Mark Goodwin, of the University of California in Berkeley, explained that they had been able to obtain a better growth series than had been available before, and this enabled them to document the changes occurring during the growth of the animals.

Big changes in the body from infancy to adulthood may have been occurred for similar reasons to changes that occur in species today that ensure members of a species recognize each other and can distinguish between adults and juveniles needing protection.

Not all paleontologists are convinced by the study. Paleontologist Hans-Dieter Sues, of the National Museum of Natural History in Washington DC agreed that some dinosaurs identified as separate species may turn out to be juveniles, since many vertebrates change in appearance as they mature. But the conclusions of the study are controversial and the claim that about a third have been misidentified is exaggerated, according to Sues. Testing the hypotheses is also difficult because there are not enough available fossils.

The research is featured in a National Geographic documentary entitled "Dinosaurs Decoded".

Always thought it was kind of odd that there were so many different dinosaur species that were so similar. Makes sense that some might just be younger versions of already-discovered species.

 

[Mitchman]

The bones were a lie?

 

[GrnMarvl14]

The bones were real, they were just misidentified.

 

[Zeta]

You have to remember sexual dimorphism, too.

Jack Horner is regarded as a nutbag amongst paleontologists, though. So I wouldn't take anything he said very seriously.

 

[Every Breaking Wave]

It doesn't surprise me. Some discoveries were made and named years ago, stored in museums, and promptly forgotten about until they were rediscovered by accident (happens more often than one might think).

Tyrannosaurus was first discovered and named as Manospondylus in the 1800s, but the fossils were lost until the early 2000s. When they were rediscovered, it was realized that the two are one and the same. Because Manospondylus has priority (ex, it was named first) Tyrannosaurus should technically be classified as a forgotten name.

 

[Zeta]

Because Manospondylus has priority (ex, it was named first) Tyrannosaurus should technically be classified as a forgotten name.

Luckily, this is one case in which priority will be quietly ignored.

 

[GrnMarvl14]

You have to remember sexual dimorphism, too.

Jack Horner is regarded as a nutbag amongst paleontologists, though. So I wouldn't take anything he said very seriously.

Am I the only one who finds it humorous that the opposite ends of this argument are Jack Horner and (let's call him Dr.) Seus? ...Nobody?

Anyway, yeah, any dino discovery needs to be taken with a grain of salt (c'mon...what's the biggest period of time we've gone without someone proving some huge aspect of dinosaurs to be false?), but this is one of those ones statements that's pretty believable. As Seus said, a third might be kind of high, but the idea that there has been some misidentification due to, as you said, gender dimorphism, and as the article said, age differences is very easy to believe and very sensible. Like if a person said that a third of all traffic cones hadn't been hit by cars.

Because Manospondylus has priority (ex, it was named first) Tyrannosaurus should technically be classified as a forgotten name.

But then you'll just end up with a Brontosaurus situation. Took me forever to work that one out (du to being told both Brontosaurus and Apatosaurus...and not what was what for years).

 

[Somari]

I saw a special on Nat. Geo today about this.

Makes sense, the evidence seems pretty good.