(News) Paul (2025) Said That Nanotyrannus Was an Eutyrannosaur!

Ah, Gregory S. Paul. Possibly the most famous paleo-artist to ever live. His 1988 book Predatory Dinosaurs of the World was the inspiration for Michael Crichton to write Jurassic Park (1990). Yet, he is known as being a notorious lumper, and is mocked ceaselessly for it. However, when someone is right you have to admit that they are. He recently had a paper published detailing the validity of the tyrannosauroids in the late Maastrichtian of North America. He concluded that there are three Tyrannosaurus species in the late Maastrichtian (T. rex, T. imperator, and T. regalis from Paul et al., 2022), and that Nanotyrannus is a valid taxon and an eutyrannosaurian.

This is a long paper (59 pages), so I'm just going to focus on the Nanotyrannus information. If I missed something, I'll add it to the post later on. It should be noted that Paul (2025) is the published version of Paul (2022) (preprint). Both versions are linked below. I will also link "Stygiovenator" into Nanotyrannus for now until I believe that it is a separate taxon. I'm down for having multiple tyrannosauroids in the late Maastrichtian of North America, but I want to be careful.

First, Paul (2025) said that Nanotyrannus (and "Stygiovenator") was an eutyrannosaurian and not a tyrannosaurid (p. 94 Figure 1; p. 117; p. 118 Figure 9; pp. 120, 126, and 128-129). I wrote my abstract for Academia saying the same thing towards the end of 2024, so it's good to see someone else say that as well. Second, Paul stated that Dryptosaurus shares “a close relationship to the long armed TT-zone baso-eutyrannosaurians,” (p. 120). He mentioned that Nanotyrannus (and "Stygiovenator") had “dryptosaur style” arms. This has been “widely discussed online” as well (p. 128). I don't want to toot my own horn, but I wonder if that was a reference to me, my friend "Luke," and others who've made that connection between Nanotyrannus and Dryptosaurus? Anyways, Paul continues to state that Nanotyrannus (and "Stygiovenator") and Dryptosaurus could potentially form a clade, but the fragmentary nature of the Dryptosaurus specimens should be put into perspective before makiing a clear decision on this (p. 128). Despite that, I think that Nanotyrannus and Dryptosaurus do form a clade. The best part about this is that Paul stated that some of the Nanotyrannus (and "Stygiovenator") specimens could potentially be Dryptosaurus aquilunguis, or be a species of Dryptosaurus (p. 128). I stated this in my abstract back in 2022! I recommend Nanotyrannus/Dryptosaurus lancensis myself nowadays, and I stated this in my 2024 abstract calling Nanotyrannus an eutyrannosaurian. Finally, Paul cited Griffin et al., (2024), which stated that the Nanotyrannus holotype CMNH 7541 was a fully-grown adult (p. 124). 

Nanotyrannus (and "Stygiovenator") and Dryptosaurus could form a clade, and some Nanotyrannus (and "Stygiovenator") specimens could potentially belong to Dryptosaurus (p. 128):

Third, Paul stated that the arms of the Nanotyrannus (and "Stygiovenator") specimens exclude them from being lumped into Tyrannosaurus. Actual juvenile, and adult, Tyrannosaurus specimens possess arm and manus bones that are shorter than the arm bones of Nanotyrannus (and "Stygiovenator"). Paul said that this physical trait links Nanotyrannus (and "Stygiovenator") to the eutyrannosaurian clade, which originated and immigrated from the East (Appalachia). Therefore, Tyrannosaurus' arms didn't shrink during ontogeny. This is also the case in the growth series of Tarbosaurus/Tyrannosaurus bataar and Gorgosaurus, which means that the more derived tyrannosaurids didn't have their arms shrink during ontogeny (pp. 118-120; p. 118 Figure 9; p. 121 Figure 11). The humerus in Nanotyrannus (and "Stygiovenator") is short, but the lower arm and manus are long (p. 120). This is also characteristic in the arm of Dryptosaurus aquilunguis (Brusatte et al., 2011, pp. 1, 5, and 46-47). Paul concludes that the arms of young T. rex specimens were smaller than the adults' (p. 126). 

Arms of Tyrannosaurus and Nanotyrannus (and "Stygiovenator") (p. 118 Figure 9):

The adult Tyrannosaurus specimens MOR 980 and FMNH PR 2081 ("Sue") have longer hands than the younger specimen UCRC PV-1. Meanwhile, the two hands of Nanotyrannus (and "Stygiovenator") on the right are longer than all three Tyrannosaurus specimens on the left and middle.

Fourth, Paul used the young Tyrannosaurus specimen BHI 6439 in his paper (p. 96; p. 116 Figure 8; p. 117, 120-121, and 126). It's been a long time since anybody even referenced the specimen, but Paul actually used it in his paper! Not only that, he used "Baby Bob" (pp. 96, 121, and 126)! I know that's s gonna be a huge criticism, but I admire Paul's guts to use those specimens. He even criticized the exclusion of such specimens on p. 128. I understand the points-of-views for both sides of the argument here, so I'll just leave it at that. Paul uses BHII 6439 and "Baby Bob" to demonstrate that the tooth counts, and tooth morphologies, of Tyrannosaurus do not change over time. They're consistent throughout the animal's lifetime (pp. 125-126). I also mentioned this on the blog before, so this is also pleasing to see stated again. Then again, Napoli (2024) (preprint) also disputed the tooth-loss theory as well. In summation, Tyrannosaurus didn't lose teeth, or change tooth morphology, nor shrink its hands as it grew older. Its ontogenetic growth was similar to that of Tarbosaurus', and other tyrannosaurids.

I do have one complaint, aside from "Stygiovenator," T. regina, and T. imperator possibly being valid. Paul lists KUI 56375 as being a juvenile T. rex (p. 116 Figure 8; p. 117). However, I remember this specimen being changed to being listed as Nanotyrannus. The maxilla of this specimen matches the morphology of Nanotyrannus as well, so I'll place it in Nanotyrannus for now.

In conclusion, this is the second paper (after Longrich and Saitta, 2024) to state that Nanotyrannus is an eutyrannosaurian, alongside Dryptosaurus aquilunguis. Heck, Paul (2025) even said that some specimens of Nanotyrannus (and "Stygiovenator") could potentially be Dryptosaurus! All of this information, along with Griffin et al., (2024) and Napoli (2024) (preprint), demonstrates that Nanotyrannus/Dryptosaurus lancensis is a distinct taxon from Tyrannosaurus. Also, this means that the ontogeny of Tyrannosaurus wasn't as extreme as previously believed. The animal had a normal tyrannosaurid ontogenetic growth curve.

Links:
Paul (2025):

https://mapress.com/mz/article/view/mesozoic.2.2.1

Paul (2022) (Preprint):

https://www.biorxiv.org/content/10.1101/2022.08.02.502517v1.full

-V2 (PDF):

https://www.biorxiv.org/content/10.1101/2022.08.02.502517v1.full.pdf

Longrich and Saitta (2024):

https://www.mdpi.com/2813-6284/2/1/1

My post on Griffin et al., (2024) (Abstract):

https://psdinosaurs.blogspot.com/2024/10/news-nanotyrannusdryptosaurus-lancensis.html

Napoli (2024) (Preprint):
https://www.biorxiv.org/content/10.1101/2024.10.25.620216v1
My 2022 abstract:

https://psdinosaurs.blogspot.com/2023/02/nanotyrannus-is-dryptosaurus-abstract_10.html
My 2024 abstract:

https://psdinosaurs.blogspot.com/2024/12/nanotyrannus-as-eutyrannosaurian.html

(Rant) Do Not Watch Jurassic World Rebirth.

It's 2:39 A.M. on June 26, 2025. It's about 80-plus degrees in my house, and I can't fall asleep. What I wrote below is something that I wrote for my "Hollywood Needs to STOP" post, but I decided to post it here so that more people can see it. I want people to expect better from Hollywood and other entertainment companies, and to get that we have to stop watching their slop until they give us a better product. 

Segment from My "Hollywood Needs to STOP" Post:
Do not watch Jurassic World Rebirth. You've already seen it. They're just regurgitating the same film that they've already made. 

I'm getting bombarded with trailers for the film now. I know that the film is coming out in July, so they're trying to gain hype for it. However, I'm asking you to NOT watch this film. It's just a rehash of Jurassic Park, The Lost World Jurassic Park, Jurassic Park 3, Jurassic World, Jurassic World Fallen Kingdom, and even Camp Cretaceous. The movie will center around Isla Sorna, they have a new dino-hybrid, probably two based on what I've seen in the trailers, they have not one but a pack of Spinosaurus now, and they're recreating classic scenes from the first film and novels. You can watch ANY of the other films in the franchise, and you would've already seen JW Rebirth. Just don't watch Jurassic World Dominion. It doesn't deserve to be watched. Ever. I would gladly watch Jurassic Park 3 over that garbage any day.

I don't know how Jurassic World Rebirth will rejuvenate the franchise when the trailers are already showing us that the franchise has nothing left to give. There's no gas left in the tank, Universal Pictures and Amblin Entertainment. It's over. The franchise should've ended after The Lost World, in my opinion. At the very least, it should've ended after Dominion. But alas, this franchise will get milked to death until it becomes like the Transformers franchise: A shell of its former self that doesn't make any money anymore at the box office (Granted, I enjoyed Transformers One but it flopped hard at the box office. I heard last week that no sequel is in development. I blame the filmmakers for not giving fans what they wanted originally, making the same film over and over again with a director who didn't want to make them anymore, and not having a plan or just ending the franchise after Dark of the Moon). I remember on Discord, about a month ago, that some of my friends posted an article saying that JW Dominion actually cost about $400-$500 million dollars to make (Wikipedia said that it costed about $200-$300 million), and that the film was a flop despite making $1 billion dollars at the box office. Hollywood needs to realize that franchises have to end, and they need to end with dignity. 

The Jurassic franchise use to mean a lot to me personally. Now, I feel nothing but apathy. The fans of this franchise will go and see it. They will waste their hard-earned money and time on this slop, and Hollywood will not learn their lesson. The cycle of mediocrity will continue. People will celebrate JW Rebirth as "the best film in the franchise since the first film," etc. As time passes on, people will look back on the film and say that it wasn't that good, overhyped, or just straight up bad. I've seen this happen before with other films in the franchise, and it will happen with JW Rebirth. All of this can be avoided by just NOT WATCHING THE FILM. But hey, what you do with your money and time is up to you, dear viewer. I've already learned my lesson. Head my warning, and vote with your wallet. Hollywood needs to learn its lesson. Do not watch Jurassic World Rebirth.

Link:
Hollywood Needs to STOP:
https://psdinosaurs.blogspot.com/2025/02/rant-hollywood-needs-to-stop.html