Tuesday 21st July 9:35 am
Brontosaurus: what’s in a name?
Tuesday 21st July 2015 9:35 am
Last time I talked about how two dinosaurs got discovered and named back in the 1870s — during the period known as the Great Discovery Rush. They were Brontosaurus andApatosaurus.
The basic problem for Brontosaurus was that it was quite similar to Apatosaurus. So after a bit of discussion, the name Brontosaurus got banished, and all the formerBrontosaurs were now supposed to be called Apatosaurus.
The field of classifying living (or extinct) creatures or plants is called ‘taxonomy’. In taxonomy, there are the ‘lumpers’ — and their exact opposite, the ‘splitters’.
The lumpers like to lump life forms together to end up with just a few groups. But the splitters like to find differences between life forms, and create lots of groups.
In 1903, about a quarter of a century after the palaeontologist, Othniel Charles Marsh, had classifiedApatosaurus and Brontosaurus as two separate ‘groups’, the lumpers in the palaeontological community won. In that year, another palaeontologist, Elmer Riggs, claimed in a worthy journal that there were not major differences between these two dinosaurs after all. As a result, bothApatosaurus and Brontosaurus were placed into the same group (or genus), Apatosaurus.
You see, there are rules in the field of taxonomy. One of the rules is that if there is a conflict, the name that was given first, gets priority. So in 1903, Apatosaurus won and Brontosaurus, even though it was a really cute name, lost.
Because it was a really cute name, the general public kept on using it. However, the palaeontologists were steadfast. In fact, in 1978, further detailed research confirmed that the name Brontosaurus should be deleted and go the way of the dinosaurs.
But nobody told United States Postal Service.
About a decade later, in 1989, they released a stamp with the word ‘Brontosaurus’ proudly emblazoned upon it. The fact that the stamp was officially launched at Disney World (definitely not a ‘proper’ museum) didn’t help them with a scientific stamp of approval. There was a huge uproar.
Surprisingly, there was a much bigger ‘mistake’ in this stamp release that the media didn’t comment on. There were four stamps issued in this dinosaur series. One of the stamps was of the flying reptile known as a Pteranodon. ButPteranodon is a flying reptile — it is not even a dinosaur!
Maybe the furore was a good measure of the interest and secret affection that people had for the nameBrontosaurus.
Even so, the name Brontosaurus was buried again — until some Portuguese and English palaeontologists decided to try to better understand the evolutionary relationships linking these four-legged, long-necked, plant-eating dinosaurs.
Emanuel Tschopp had chosen this topic for his PhD thesis at the New University of Lisbon. He was trying to generate a high-resolution family tree of the sauropods (such as Apatosaurus).
He and his colleagues were extraordinarily thorough.
They measured some 477 individual features (or characteristics) of fossilised dinosaur bones — features such as length, various bumps, distances between bumps, shapes of the bumps, and so on. Now there are a lot of bones in a dinosaur. So they did this for every bone of each of 81 separate relevant sauropod skeletons stored in dozens of museums scattered around the world. The amount of work to be done was simply enormous. While some of the bones are huge and heavy, they are also fragile, so collecting data can be painfully slow. This monumental task took five years.
At the end of it, the bones revealed their secrets.
The palaeontologists now (more than ever before) had a deeper understanding of how to classify these long-necked herbivores. And getting back to Brontosaurus, this led to a slight ‘rearrangement’ of the family tree.
Dr Tschopp, the lead author of the paper later said: “I didn’t start out trying to resurrect Brontosaurus.” But accidentally, that’s what he did.
He had to. There were so many significant differences in the bones that Brontosaurus was again split off fromApatosaurus into its own separate genus. For example, Apatosaurus had a more robust body and a more bulky neck than Brontosaurus.
Brontosaurus, which was now split even further into three separate species, had longer bones in the ankle as compared to Apatosaurus, and had a rounded edge on the shoulder blade.
Brontosaurus rose, fell, and rose again. So now, thanks to five years of some very detailed research, and a garguantuan scientific paper nearly 300 pages long, the splitters have won — and the lumpers just have to lump it.
Brontosaurus is back out of the shadows. But unfortunately, they have resuscitated only the name, not the actual living dinosaur …
This blog first appeared on Dr Karl's Great Moments in Science
© 2016 Karl S. Kruszelnicki Pty Ltd