Nanotyrannus and the Ontogeny of Tyrannosaurus rex
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- Опубликовано: 1 окт 2024
- In this video, I examine the controversy over Nanotyrannus, a possible Tyrannosaurus rex youngster!
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What is your opinion on the "Bob" T rex specimen? It's a juvenile specimen that's supposedly younger than "Jane". It looks nothing like a Nanotyrannus
It’s a 4 year old rex
In 30 seconds I went from never heard of this guy, to damn what a legend
Same case for me lol.
Are there no juvenile TRex fossils? The show I saw early today shows fossils of Nano that had very much longer arms than adult TRex. Does this matter?
At the Black Hills Institute, they have the lower jaw of a Juvenile Tyrannosaurus, teeth matching the adults.
@@The_PokeSaurus don’t forget the baby rex in the University of Kansas, it has 12-13 teeth in the maxilla
@@lukeskywalkerjediknight2.013 Ah really? Another museum I should visit. And another example of a REAL Juvenile Tyrannosaurus.
@@The_PokeSaurus Yeah they have a few true juvenile rexes. Here is a list of the different ages of Rex (the nanotyrannus skulls is only there to show the tooth count):
Baby Bob" has 12 dentary teeth and is estimated to be 4 years old.
CMNH 7541 a.k.a "Cleveland Skull" has 16 dentary teeth and is estimated to be somewhere between "Baby Bob" and "Jane" in age given size, but closer to "Jane".
KUVP 156375 in the KU collection is of comparable age to "Jane" and has 12 maxillary teeth.
"Jane" a.k.a BMRP 2002.4.1 has 17 dentary teeth and is estimated to be 11 years old.
LACM 23845 doesn't have a complete jaw but appears to have has 12-14 dentary teeth if you reconstruct the missing parts and is estimated to be 14 years old.
“MOR 555 has 12 dentary teeth and is estimated to be 16 years old.
“B-Rex" a.k.a MOR 1125 has 14 dentary teeth and is estimated to be 16-20 years old.
MOR 008 has 13 dentary teeth and is estimated to be 22 years old.
“Sue" a.k.a FMNH PR2081 has 13 dentary teeth and is estimated to be 28 years old.
@@lukeskywalkerjediknight2.013 Hmm. Fascinating.
If you look at comparison pictures across the discovered T-Rexs, you'll also notice fairly wide differences in skull depth, length, the various ridges... T-rex individuals could be quite distinctive. T-rexs appear to start out fairly quick and gracile, and slowly develop the massive muscle attachments and bulk in bone to anchor those muscles. I suspect from the region map the author has displayed that, like some sharks, there were particular areas where T-Rexs preferred to brood their young. Those young would tend to stick around that brooding site until they were old enough to challenge or avoid their older generation. If so, future discovery might locate the nesting areas, close by to where the juvenile Rexs tended to be found.
It's a stretch to compare Tyrannosaurus speculative behavior to those of sharks.
Whether a juvenile T. rex or a different smaller species it's fossil skull is drop dead gorgeous, Bakker himself summed it up best in a March 1992 issue of Discovery magazine titles *Inside the Head of a Tiny T.Rex* where he writes "a high-tech predator that combined the eyes and brain of an eagle with the snout and hearing of a wolf." The fossil asks many questions, even Tom Holtz notes "The turbinals are very interesting"
Tyrannosaurus was actually much less intelligent than a modern eagle
PaleoAdventures Paleontologist "Walter W. Stein" finds a big tooth of a big Nanotyrannus found on the site called "Tooth Draw Quarry" in the Hell Creek Formation in Butte County, South Dakota.
👍 you are teaching us excellently
Charlie Gilmore looks like a fun guy.
You lightly address the very very differences that set Nano apart from T.rex but you completely ignore all the specimens that clearly show Juv T.rex was MUCH more robust and highly divergent from the known examples of Nano.
So if the dwarfism can't be a factor because the Nanotyrannus wasn't isolated then couldn't the opposite be true for the Tyrannosaurus Rex? Where part of the Nanotyrannus population split off to roam a bigger area and thus causing Gigantism?
Younger tyrannosaurs would probably have kept their distance from adults
the 'dueling dinosaurs' are now the property of the NC Museum of Natural History, and will be displayed in its new wing
I used to believe nanotyrannus is a different genus as rex
I have been redeemed
Brilliant lecture. Greatly appreciated.
Goldberg and gillberg
Great job! I enjoyed watching during my research!!
Actually, birds tend towards the opposite, i.e., their skulls as chicks are proportionally shorter than their adult skulls because beaks will elongate with maturity. Toucans and herons for example. It's not universally the case but in many families it is. That said, there definitely seems to be more evidence to support 'Nanotyrannus' as a juvenile T. rex than a separate genus, although I wish it weren't the case.
I think it's probably fair to say that looking at modern birds and using that to extrapolate details about non avian dinosaurs probably only goes so far. Obviously a beak develops differently than toothed jaws, and I'd assume the fact that birds are usually fed by their parents probably changes things, not to mention diet. Given the data we have now it's fair to say that, whether nano existed or not, juvenile Tyrannosaurs had a very different build and niche to the adults.
@@seanmckelvey6618 Yes, I agree that using modern birds as perfect analogs is limiting. An enormous amount of evolution has occurred since the Cretaceous.
As a an interested amateur it may well be I'm about to spout obvious nonsense to anyone who actually knows what they are talking about, but here goes.
I have a strong suspicion that 'we' erect far too many new species when it comes to fossils, especially so where 'Dinosaurs' are concerned. The subject at had being Nanotyrannus, but I bet a more egregious example is the very many 'species' of ceratopsians that have been named. I suspect for any geological stratum most ceratopsians that are labelled as separate species are actually developmental stages of a far lower diversity.
Why? I suspect it's our 'mammalian bias'.
As we look at the natural world today most large animals are mammals and the few that aren't are not 'dinosaurs'. Loosely speaking we see every ecological niche inhabited by a single species, and so see 'dinos' the same way. But when I look at the paleontological record with my inexpert eye I see something very different. Rather than a large number of species, each inhabiting their own niche, I see a small number of species 'vertically' inhabiting several niches. Unlike mammals where a juvenile is an 'adult in waiting', for dinosaurs each stage of development is very much it's own thing with it's own physical characters and niche. Throughout it's life an individual dinosaur will move through several distinct morphotypes and associated niches, I presume ending with one that includes sexual maturity. That sexual maturity may in itself my be influenced as much by the makeup of a species total population as it does the age or size of the beast - rather like some fish, although this latter thought is pure guesswork on my part.
We are fooled further by crocodilians and 'birds', being those examples most closely related to 'dinosaurs'. For the most part crocs only grow with age, which might be considered a 'primitive' feature. 'Birds', although dinosaurs, for the most part don't display normal dinosaur 'plasticity' in their morphotypes and niches as they develop because they are not normal dinosaurs - they are constrained by their specialism for flight and all that requires.
In essence if one was to look on a scene of Cretaceous dinosaurs your 'mammalian eye' might see a great diversity of different creatures and assume they really are different. But if one was to look over time it would turn out that at a species level the diversity is very low and what one actually is seeing is a lot of morphotypes based on age, maturity, and maybe even influenced interactions between species members and their environment.
A long way of saying I bet 'Nanotyrannus' is just one example of a 'baby' being mislabelled as a separate species because 'dinosaurs' don't just get bigger as they mature.
I suspect this idea, if it has any value, might help explain a few other things. eg:
-How come 'dinosaurs' seem to have so much potential for evolutionary change, and yet there are specific niches like marine life that they never entered? Maybe because every individual has coding for several different morphotypes wrapped in from the off. A small change would easily result in something very different, and yet viable, for such a creature. But also being the supreme 'morphotype generalists' they always carried too much 'baggage' to, a-hem, dive in to the role of a 'fish'. It's interesting that in my view 'birds' must have ditched this 'morphotype plasticity' so they could become super-specialists.
-Why did all the 'dinosaurs' die out but not other lineages, and not the 'birds'? Well, there are lots of good theories for this but this suggestion presents another option. If much of 'dinosaur diversity' was in multiple morphotypes for each species rather than many species you have two effects. First, you have low overall diversity of actual 'lineages', and low diversity ecosystems tend to be easier to push over. Second, every time a specific 'dinosaur' species bites the dust you don't just loose that single species you loose all it's associated individual morphotypes from the ecosystem, each one of which was occupying it's own niche. That would be a great way to see the sudden collapse of an entire ecosystem as not only are you loosing multiple 'contributors' in one shot you are likely to hit 'keystone' morphotypes pretty frequently too. Also a disaster can 'target' any specific 'morphotype' and there's a good chance that whole chain will be gone in short order.
'Birds' being more like other groups in which each species occupies only one niche would be less effected by environmental catastrophe as when a species is taken out you only loose the occupier of one niche, and also with each 'bird' species being a much smaller proportion of the totality of birds it's less of a disaster to the whole group when one is lost.
...and then there's the issue of finding a mate in an unhealthy ecosystem. A badger is a badger, young or old. Sooner or later all remaining badgers will be able to breed. But a 'Nanotyrannus' is not a 'T.Rex'... as far as the individuals of either morphotype are concerned, at least not for now. If I'm a hungry 'T. Rex' a 'Nanotyrannus' is going to look like food not a potential mate, and if I'm a 'Nanotyrannus' I probably don't know what sex is.
I'm rambling.
"Nanotyrannus"
Me: you mean tyrannosaurus rex?
That statement will not age well.
@@The_PokeSaurus Hopefully.
Wait i thought tarbosaurus bataar being in the tyranosaurid family was debunked because of thier difference in skelatal structures
What??
Where did you even read that?
Tarbosaurus is and will always be a Tyrannosaurid
I've talked to Robert Bakker himself on this topic, and as a person who once thought Nanotyrannus was just a Juvenile Tyrannosaurus, I can say with full confidence it is its own genus.
Nanotyrannus and Tyrannosaurus Rex has differently shaped teeth, now you may try explaining this with Ontogeny but that doesn't work because no other theropods in the Fossil Record changed their tooth shape that dramatically as they age, and at the Black Hills Institute where Stan once lived, they actually have the lower jaw of a real Juvenile Tyrannosaurus and its the same size as the Nanotyrannus specimens we've found but its teeth match an adult Tyrannosaurus exactly.
Edit: That lower jaw is actually a cast.
Rip Stan 😔
@@lukeskywalkerjediknight2.013 I wanna visit the Black Hills Institue to both see the Real Juvenile Tyrannosaurus bones, and support them after losing Stan.
@@The_PokeSaurus I have been able to see a true Juvi Rex when I was at Tucson (Baby Bob)
@@lukeskywalkerjediknight2.013 Ahhh, nice!
@@The_PokeSaurus Ye, annoying that it costs 2-5 million $