Questions about the Giant Tyrannosaurid species Tyrannosaurus mcraeensis and Cretaceous Tyrannosaurid diversity

[Joseph Fossil]

Perhaps one of the most exciting scientific papers in a while about the genetic diversity of the Tyrannosaurid genus Tyrannosarus itself (the genus that includes the famous and well documented T-rex) was just announced and published (or at least the abstract of it)!!!

 

 

Image Credit: Dalman et al. 2023 (abstract) and the Society for Vertebrate  Paleontology (SVP).

https://vertpaleo.org/wp-content/uploads/2023/10/2023_SVP_Program-Final-10032023.pdf

 

 

At the Society for Vertebrate Paleontology's annual meeting for 2023, Paleontologists Dr. Sebastian Dalman, Dr. Philip J. Currie, and seven other experienced Paleontologists and experts on the Tyrannosaurid theropod dinosaurs published an abstract on October 21, 2023 about a new species of Tyrannosaurus (Tyrannosaurus mcraensis) from the Hall Lake Formation dating 72 Million Years ago to the Campanian-Maastrichtian Cretaceous of what is now New Mexico!!!

 

This not only gives insights on the origins of the genus Tyrannosaurus, but validates previous hypothesis over the years (at least since 2013) that a unique giant Tyrannosaur from southern Larmidia (now Western North America) that lived during the Campanian-Maastrichtian Cretaceous!!! Names given to this animal over the years include Alamotyrannus brinkmani and Tyrannosaurus brinkmani.

 

 

A Digital Reconstruction of the Tyrannosaurus species Tyrannosaurus mcraensis and it's size compared to an average Human, April 2022.

Image Credit: Artist LancianIdolatry

https://twitter.com/LancianIdolatry/status/1511016414252978182

 

This is especially true given for how long the debate has been raging  on the Validity ofThe species Tyrannosaurus mcraensis was when fully grown the same size of the averaged size adults of the later Tyrannosaurus rex from the later Maastrichtian Cretaceous. 

 

By the look of things with the Paper and the experienced paleontologists and Tyrannosaur experts who authored it, it seems just by looking at its abstract it will be be far more through and accurate than the recent Gregory S. Paul Paper from 2022 and maybe even prove the validity of the debate Tyrannosaur species Tyrannosaurus vannus from the 70-66 Million Years ago dated Javelina Formation of what is now Texas. 

 

 

But I'm wondering if anyone has more information on this study and the potential of it's results?

[Joseph Fossil]

I've heard too that tyrannosaurid fossil specimens from the McRae Formation in what is now New Mexico and the Ojo Alamo Formation in what is now Texas might belong to this new Tyrannosaurus species.

 

Some Images of the Tyrannosaurid fossil specimens found at the McRae Formation.

Image Credit: Gillette et al. 1986 and the New Mexico Geological Society

https://nmgs.nmt.edu/publications/guidebooks/downloads/37/37_p0235_p0238.pdf

 

 

 

I'm also wondering if anyone was there at the SVP meeting when the paper abstract was announced, what you think of the paper, how could this impact the study of the Campanian Tyrannosaur fossil specimen CM 9401 from what is now Montana, and how could it overall imopact the study of Late Cretaceous Tyrannosaur diversity?

 

[Joseph Fossil]

@FossilDAWG @Nick G. Any thoughts you guys? What do you think of the paper abstract? 

[CrankyPongine]

When is the paper gonna be released in its entirety 

[Joseph Fossil]

On 11/7/2023 at 4:15 PM, CrankyPongine said:

When is the paper gonna be released in its entirety 

 

@CrankyPongine I don't know. I hope it's released soon.

[Psittacosaur9]

It will be interesting to see if this becomes accepted by most in the community apart from a couple of fringe theorists, or if we will have another 'Nanotyrannus' situation on our hands.

[DD1991]

The tyrannosaurine fossil from the Hall Lake Formation of New Mexico is now officially described as a new species:

 

Dalman, S. G, Loewen, M. A., Pyron, R. A., Jasinski, S. E., Malinzak, D. E., Lucas, S. G., Fiorillo, A. R., Currie, P. J., and Longrich, N. R., 2024. A giant tyrannosaur from the Campanian–Maastrichtian of southern North America and the evolution of tyrannosaurid gigantism. Scientific Reports 13. Article number 22124. doi:10.1038/s41598-023-47011-0. 

 

The description of the Elephant Butte Tyrannosaurus as the new species T. mcraeensis lends some support to a number of suggestions in the past that the maxilla TMM 41436-1 found in the Javelina Formation of Big Bend National Park in western Texas and originally dubbed "Tyrannosaurus vannus" in a 1972 thesis by Douglas Lawson (discoverer of Quetzalcoatlus) might not be Tyrannosaurus rex, but it also bolsters skepticism by Sullivan and Lucas (2015) about NMMNH P-3698 being truly referrable to Tyrannosaurus rex. The estimated age by Dalman et al. (2024) for T. mcraeensis in the "Systematic paleontology" section of their paper is a bit too broad because only one radiometric date has been obtained from the Hall Lake Formation, but the age of 69 million years old for NMMNH P-3698 given by tip-dated phylogenetic analysis makes sense given past identification of T. mcraeensis as T. rex and hews very closely to Sullivan and Lucas (2015) estimating T. mcraeensis to be 67 million years old.

 

As a side note, NMMNH P-3698 was originally catalogued as NMMNH P-1013-1, but the NMMNH curators changed the catalog number for the T. mcraeensis holotype because the catalog number NMMNH P-1013 had been allocated to a premolar tooth from the Paleocene-age Nacimiento Formation in New Mexico very similar to the multituberculate mammal genus Xanclomys.

 

Lawson, D., 1972. Paleoecology of the Tornillo Formation, Big Bend National Park, Brewster County, Texas. Masters thesis. University of Texas. 182 pp.
 

Sullivan, R.M., and Lucas, S.G., 2015. Cretaceous vertebrates of New Mexico, in Lucas, S.G., and Sullivan, R.M., eds., Fossil vertebrates in New Mexico. New Mexico Museum of Natural History and Science Bulletin 68: 105–129.

[Joseph Fossil]

22 hours ago, DD1991 said:

The tyrannosaurine fossil from the Hall Lake Formation of New Mexico is now officially described as a new species:

 

Dalman, S. G, Loewen, M. A., Pyron, R. A., Jasinski, S. E., Malinzak, D. E., Lucas, S. G., Fiorillo, A. R., Currie, P. J., and Longrich, N. R., 2024. A giant tyrannosaur from the Campanian–Maastrichtian of southern North America and the evolution of tyrannosaurid gigantism. Scientific Reports 13. Article number 22124. doi:10.1038/s41598-023-47011-0. 

 

The description of the Elephant Butte Tyrannosaurus as the new species T. mcraeensis lends some support to a number of suggestions in the past that the maxilla TMM 41436-1 found in the Javelina Formation of Big Bend National Park in western Texas and originally dubbed "Tyrannosaurus vannus" in a 1972 thesis by Douglas Lawson (discoverer of Quetzalcoatlus) might not be Tyrannosaurus rex, but it also bolsters skepticism by Sullivan and Lucas (2015) about NMMNH P-3698 being truly referrable to Tyrannosaurus rex. The estimated age by Dalman et al. (2024) for T. mcraeensis in the "Systematic paleontology" section of their paper is a bit too broad because only one radiometric date has been obtained from the Hall Lake Formation, but the age of 69 million years old for NMMNH P-3698 given by tip-dated phylogenetic analysis makes sense given past identification of T. mcraeensis as T. rex and hews very closely to Sullivan and Lucas (2015) estimating T. mcraeensis to be 67 million years old.

 

As a side note, NMMNH P-3698 was originally catalogued as NMMNH P-1013-1, but the NMMNH curators changed the catalog number for the T. mcraeensis holotype because the catalog number NMMNH P-1013 had been allocated to a premolar tooth from the Paleocene-age Nacimiento Formation in New Mexico very similar to the multituberculate mammal genus Xanclomys.

 

Lawson, D., 1972. Paleoecology of the Tornillo Formation, Big Bend National Park, Brewster County, Texas. Masters thesis. University of Texas. 182 pp.
 

Sullivan, R.M., and Lucas, S.G., 2015. Cretaceous vertebrates of New Mexico, in Lucas, S.G., and Sullivan, R.M., eds., Fossil vertebrates in New Mexico. New Mexico Museum of Natural History and Science Bulletin 68: 105–129.

 

@DD1991 Thanks for letting me know bro about the change in NMMNH specimen catalogue number and the publication of the Tyrannosaurus mcraensis description paper! I really do appreciate it!!

[rocket]

On 11/16/2023 at 9:40 AM, Psittacosaur9 said:

It will be interesting to see if this becomes accepted by most in the community apart from a couple of fringe theorists, or if we will have another 'Nanotyrannus' situation on our hands.

 

Certain risk..., I think we will get another "Nanotyrannus"-situation as well, it is a scientific field that is currently developing rapidly...

[NickG]

On 1/12/2024 at 2:23 PM, Joseph Fossil said:

 

@DD1991 Thanks for letting me know bro about the change in NMMNH specimen catalogue number and the publication of the Tyrannosaurus mcraensis description paper! I really do appreciate it!!

“mcraeensis”, there’s two e’s