Can’t Get Dino Species Right? What Else Is Wrong?
Posted by: Loren Coleman on October 14th, 2009
Within cryptozoology, several lines of thought revolve around using fossil forms as possible candidates for what cryptids might be. Within the study of fossils, however, there is a cautionary tale evolving about what at first glance seems so obvious one wonders why it has not been considered earlier. The new theory emerging is that some of the smaller dinosaur species may merely be the young of larger adult forms.
Brian Handwerk pens a good overview of the new theory for National Geographic News, of which below is a selection.
Many dinosaurs may be facing a new kind of extinction—a controversial theory suggests as many as a third of all known dinosaur species never existed in the first place.
That’s because young dinosaurs didn’t look like Mini-Me versions of their parents, according to new analyses by paleontologists Mark Goodwin, University of California, Berkeley, and Jack Horner, of Montana State University.
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.
Nanotyrannus shown in scale to the typical 6 ft tall Homo sapiens (often seen in height charts).
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.
Tyrannosaurus rex shown in scale to the typical 6 ft tall Homo sapiens.
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.
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Birds of a Feather
Clues to why dinosaurs underwent such dramatic physical changes may be found in their closest living relatives—birds experts say.
Hornbills, for example, don’t sport their distinctive helmet-like head casque (see hornbill picture – at top) until they are about three-quarters grown.
Like deer antlers, the casque helps other animals discern between mature adults and juveniles.
In the same way, dinosaurs’ changing appearances might have also promoted visual communication.
For example head knobs or horns, likely paired with color variations, may have created unmistakable visual displays that made sure members of a species recognized one another.
They may also have identified dinosaurs as male or female and marked them as mate-seeking breeders or juveniles in need of protection.
* * *
This specific height chart design is by Snorg Tees.
About Loren Coleman
Loren Coleman is one of the world’s leading cryptozoologists, some say “the” leading living cryptozoologist. Certainly, he is acknowledged as the current living American researcher and writer who has most popularized cryptozoology in the late 20th and early 21st centuries.
Starting his fieldwork and investigations in 1960, after traveling and trekking extensively in pursuit of cryptozoological mysteries, Coleman began writing to share his experiences in 1969. An honorary member of Ivan T. Sanderson’s Society for the Investigation of the Unexplained in the 1970s, Coleman has been bestowed with similar honorary memberships of the North Idaho College Cryptozoology Club in 1983, and in subsequent years, that of the British Columbia Scientific Cryptozoology Club, CryptoSafari International, and other international organizations. He was also a Life Member and Benefactor of the International Society of Cryptozoology (now-defunct).
Loren Coleman’s daily blog, as a member of the Cryptomundo Team, served as an ongoing avenue of communication for the ever-growing body of cryptozoo news from 2005 through 2013. He returned as an infrequent contributor beginning Halloween week of 2015.
Coleman is the founder in 2003, and current director of the International Cryptozoology Museum in Portland, Maine.
So, in summary, the growing process of extinct dinosaurs is not fully understood. For example, what if archeologists in the future classify baby Komodo dragons (arboreal lizads) and adult Komodo (4-legged Godzillas) as different species?
That Nanotyranus size comparison is not accurate; the original specimen was about 17′ long.
Yes. “The original Nanotyrannus specimen is estimated to have been around 17 feet (5.2 meters) long when it died,” according to Wikipedia.
Maybe this is a newborn, and not a larger, grown specimen? Most living things begin very much smaller than when they die, correct?
Or perhaps this is a drawing of Nanotyrannus in comparison to a True Giant?
🙂
Considerations of sexual dimorphism has also rendered many species names obsolete.
I want the t-shirt. (I’d be running for sure.)
I was also surprised to see a way teeny Nanotyrannus.
But once again, all we have is speculation. It makes sense to revise speculation based on further evidence; but it remains speculation, as we’ll never see one alive. Almost nothing we “know” about dinosaurs is really knowledge. Intelligent reasoning, based on considerable evidence, but you can touch a coelacanth. (If you catch one.)
Seems very interesting and there are bound to be some new matches. Might show new light on rearing of young etc etc. Including if a second look showed the young were unlikely to be able to feed themselves. May be suggesting parental care or if there was some indication the young fed on some part of the parents body or on regurgetated food. Even something analagous to ‘pigeons milk’
There could of course be ramifications for cryptozoology giving more interest in the possibilty of same, instead of different species.
DWA
I quote you
”But once again, all we have is speculation. It makes sense to revise speculation based on further evidence; but it remains speculation, as we’ll never see one alive. Almost nothing we “know” about dinosaurs is really knowledge. Intelligent reasoning, based on considerable evidence, but you can touch a coelacanth. (If you catch one.)”
Are you not being rather absolutist about proof? With dinosaurs its not all speculation and if not the speculation can be limited. For example an adult tyrannosaurus was large, is this not proven. It is not absolutely known if it was a scavenger or a hunter and here we have speculation, not the guesswork interpretation but the theorising interpretation within limits
Now off to make some more of the usual daily arbitrary decisions about this and that.
“what if archeologists in the future classify baby Komodo dragons (arboreal lizads) and adult Komodo (4-legged Godzillas) as different species?”
Well, they would be some really weird archeologists for one thing, they don’t typically classify reptiles :). I don’t really understand the hype around this. Concerns about picking fossil adults from fossil juveniles has been with us for a long time, Nanotyrannus was a controversial species to begin with for this very reason. One problem is that there are literally about 20 definitions for what a species constitutes depending on what field of study you are engaged in. The traditional definition that jumps to mind is that a species is a group of organisms that can produce fertile offspring, given favorable circumstances. There is nothing wrong with this per se, but it does become very complicated when working with fossil specimens.
Loren, your title’s caveat of “What else is wrong?” seems a little over the top. There is still very much we don’t or can’t know. The important thing to remember is that science is a self-correcting, human endevor that attempts to explain our world, there is no final word on virtually any subject.
Loren:
I had read about this somewhere else on the Internet and was wondering when you were going to bring it up. Thanks for doing so!!!
Big surprise…Dinosaur Science is NOT set in stone!!! Not Black and White!!!
In the words of John Henson of the late, great, still missed show “Talk Soup”—
“WOW!!!” (Sarcasm added). 🙂
Seriously, though—
I actually happen to agree with Drtachyon:
“The important thing to remember is that science is a self-correcting, human endevor that attempts to explain our world, there is no final word on virtually any subject.”
Amen to that.
I also agree in some things with Both Dwa AND Norman-Uk.
I just wish scientists would not be so quick to declare certain things as being “definitive” when there ARE “no final word on any subject.”
Some may disagree and say that scientists are NOT definitive about anything. I would disagree with that. But that’s me.
Karl Popper (no “mean” philosopher of science, wouldn’t you say?) said it best: “All knowledge is tentative.” 🙂
What do you mean, “not set in stone”?
That’s where most fossils are found, set in stone; they are stone, for Pete’s sake! Had to get that out of my system.
In all seriousness, we never really will completely understand dinosaurs, how can we? They died out (well most of them) millions of years ago.
“Well, they would be some really weird archeologists for one thing, they don’t typically classify reptiles :). I don’t really understand the hype around this”
Dear Drtachyion.
I think I didn’t explained my example in detail. Let us assume that a meteor comes right now, the actual animals go extinct and some different species evolve afer that (just like at the end of the Cretaceous). From these one species, one becomes intellignt after many millions of years and develops a civilization. They produce their own archeologists, who do digging in Komodo Island, find the rests of a baby Komodo dragon and an adult. Will they classify them as different species, or they will be able to reconstruct the growing process of Komodus varanensis?
Greetings.
Kronprinz_adam,
Perhaps I wasn’t being clear…I was being a smart-ass pointing out that archaeologists don’t study Komodo dragons, sorry about that. As a paleontologist, I hear this confusion quite a lot and didn’t mean any offense. Your clarified point is well taken. Ontogeny of any species, living or fossils, can only really be understood by having examples of the animals at different life stages, something rarely seen in the fossils record. While I’m not a vertebrate specialist, I think there are ways to tell juvenile specimens from adults, looking at things like calcification of long bones and digits, position of teeth in the jaw, and comparison with similar living organisms. Paleontological material is often very fragmented and it can be difficult to identify which taxa a specimen belongs to, let alone it’s maturity. This obviously requires the skills of an expert in modern animal groups, which most paleontologist who specialize in a particular group of organisms becomes. Given the necessary degree of expertise in modern critters most paleo-folks need and the suite of characteristic juvenile features shared by many vertebrates, I would be surprised if more than a small fraction of juvenile fossil forms have been mischaracterized as new species. In addition, the bias against immature vertebrates being fossilized to begin with is very high, given that they were, on the whole, bite-sized and had poorly calcified skeletons.
If there is an expectation that nearly all fossils are going to be of adults, then this is what will be found, leading to errors as has been suggested. On the face of it, seemingly the fossils of more adults will be found because of more and tougher bone to fossilise. But the younger an animal, is the more there are and the more casualities there are, the numbers falling off with age. This might well compensate for larger, tougher bones and this will vary with species and the environments in which they lived and died. Of course smaller is harder to find and smaller is harder to classify too!
It seems the time has come for some sort of review of the situation, with an open mind, as it seems possible there is a tendency for the default position to be, ”another species” with the kudos that brings.
The nice thing about finding young and old, male and female of a species, is how this gives a hugh new dimension to what is known of that species ! Equivalent to colour TV instead of black and white and 3D instead of 2D! Much greater potential for interest and knowlege.