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Number of Tyrannosauridae genera in Western and Eastern North America during the Maastrichtian Cretaceous


Joseph Fossil

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Along with an interest in Pennsylvanian fish diversity, I've also had an interest (like many others studying Paleontology) in the diversity of Dinosaur genera during the Cretaceous era (particularly the Theropod diversity in North America during the Maastrichtian period 72.1-66 Million years ago). Compared to the preceding Campanian period (83.6-72.1 Million years ago), I've noticed there is a slightly less number of known Tyannosauridae genera in Western North America (at the time a separate continent known as Laramidia). I've come up with a list of confirmed known and possible Tyrannosauridae genera during the Maastrichtian period in Western North America and Eastern North America.

 

Eastern North America (at the time a separate continent known as Appalachia)

 

Dryptosaurus 

 

Donoho Creek Formation Tyrannosauridae genera (possibly Appalachiosaurus)

 

https://palaeo-electronica.org/content/2018/2123-appalachia-biogeography

 

Chronister well (Ripley Formation) Tyrannosauridae genera

 

http://www.fossilworks.org/cgi-bin/bridge.pl?a=collectionSearch&taxon_no=38606&max_interval=Cretaceous&country=United States&state=Missouri&is_real_user=1&basic=yes&type=view&match_subgenera=1

 

 

Western North America (Laramidia)

 

Tyrannosaurus Rex

 

Nanuqsaurus (Prince Creek Formation)

 

Albertosaurus (more early Maastrichtian to around 68 Million Years ago)

 

?"Alamotyrannus" (could also be a species of Tyrannosaurus - ?Tyrannosaurus brinkmani) 

 

?"Daspletosaurus sp. (Horseshoe Canyon Formation) (specimen CMN 11315) (more early Maastrichtian to around 68 Million Years ago)

 

https://cdnsciencepub.com/doi/10.1139/cjes-2014-0072

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7079176/

 

 

I'm wondering if this is an accurate list, why is there a dip in Tyrannosauridae diversity in Eastern and Western North America after the Campanian (was it a result of the Deccan Volcanic eruptions in India around the same time, at least for Western North America (if this theory is current) the Native Western North American Tyrannosaur genera being outcompeted by the Eurasian ancestors of Tyrannosaurus Rex arriving in North America via a land bridge during the late Campanian Early Maastrichtian, or both), the status on the taxonomic validity of Alamotyrannus, was Nanuqusaurus present during the later part of the Maastrichtian, and did Albertosaurus and Tyrannosaurus Rex ever come into direct contact with one another?

 

 

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The current described list of North American Tyrannosauridae is shown in the attached topic and the deposit they are found in.   Its significantly different than yours.  All are part of the continent of Laramidia.   Dryptosaurus and Appalachiosaurus are not a Tyrannosauridae but a Tyrannosauroidea and part of the Appalachia fauna.

 

 

 

 

this illustration is from 2016 and a bit out of date but can give you a sense of when these dinosaurs existed.   Albertosaurus existed late Campanian early Maastrichtian while T rex was late Maastrichtian.

 

Tyr.thumb.JPG.46a658ce848a3c3757ea60793771be79.JPG

 

Brusatte et al. 2016 New Tyrannosaur from the mid cretaceous of Uzbekistan

 

 

Paper on Maastrichtian diversity

DiversityPaper.pdf

 

 

Screenshot_20221106-190834_Drive.jpg.d56890f46524266eb3d0e1c519bfe416.jpg

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10 hours ago, Joseph Fossil said:

Tyrannosauridae genera during the Maastrichtian period in Western North America and Eastern North America.

 

10 hours ago, Joseph Fossil said:

Donoho Creek Formation Tyrannosauridae genera (possibly Appalachiosaurus)


The Donoho Creek Formation is Campanian.

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14 hours ago, Troodon said:

 

The current described list of North American Tyrannosauridae is shown in the attached topic and the deposit they are found in.   Its significantly different than yours.  All are part of the continent of Laramidia.   Dryptosaurus and Appalachiosaurus are not a Tyrannosauridae but a Tyrannosauroidea and part of the Appalachia fauna.

 

 

 

 

this illustration is from 2016 and a bit out of date but can give you a sense of when these dinosaurs existed.   Albertosaurus existed late Campanian early Maastrichtian while T rex was late Maastrichtian.

 

Tyr.thumb.JPG.46a658ce848a3c3757ea60793771be79.JPG

 

Brusatte et al. 2016 New Tyrannosaur from the mid cretaceous of Uzbekistan

 

 

Paper on Maastrichtian diversity

 

s12549-018-0327-2.pdf 4.97 MB · 2 downloads

 

Screenshot_20221106-190834_Drive.jpg.d56890f46524266eb3d0e1c519bfe416.jpg

 

@Troodon Thank you for the input. I knew that some like Albertosaurus were more from the early Maastrichtian (I've also seen the chart you sent before, it's a pretty good chart). I am still wondering (as I do notice there is the tiniest time match with Tyrannosaurus and Albertosaurus) if Tyrannosaurus and Albertosaurus  ever came into contact with one another? 

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14 hours ago, Troodon said:

 

The current described list of North American Tyrannosauridae is shown in the attached topic and the deposit they are found in.   Its significantly different than yours.  All are part of the continent of Laramidia.   Dryptosaurus and Appalachiosaurus are not a Tyrannosauridae but a Tyrannosauroidea and part of the Appalachia fauna.

 

 

 

 

this illustration is from 2016 and a bit out of date but can give you a sense of when these dinosaurs existed.   Albertosaurus existed late Campanian early Maastrichtian while T rex was late Maastrichtian.

 

Tyr.thumb.JPG.46a658ce848a3c3757ea60793771be79.JPG

 

Brusatte et al. 2016 New Tyrannosaur from the mid cretaceous of Uzbekistan

 

 

Paper on Maastrichtian diversity

 

s12549-018-0327-2.pdf 4.97 MB · 2 downloads

 

Screenshot_20221106-190834_Drive.jpg.d56890f46524266eb3d0e1c519bfe416.jpg

 

@Troodon Also, Nanuqusaurus is not featured in the chart and I don't also believe the supposed Horseshoe Canyon Daspletosaurus sp. (which I personally believe could be a relict descendent of Daspletosaurus, could actually is a juvenile Albertosaurus, or a completely new Tyrannosaur genus) was figured in this chart either. Thanks for pointing out the difference between Tyrannosauridae and Tyrannosauroidea (sometimes I get the two terms mixed up)!

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22 minutes ago, Joseph Fossil said:

Albertosaurus  ever came into contact with one another? 

Nothing has been published

 

14 minutes ago, Joseph Fossil said:

Also, Nanuqusaurus is not featured in the chart

That chart was not meant to be all inclusive and focused on Uzbekistans new Tyrannosauroid.

14 minutes ago, Joseph Fossil said:

Horseshoe Canyon Daspletosaurus sp.

The following publication describes that specimen as a juvenile Albertosaurus

 

A Problematic Tyrannosaurid
(Dinosauria: Theropoda) Skeleton
and Its Implications for Tyrannosaurid Diversity in the Horseshoe Canyon Formation 2019 (Upper Cretaceous) of Alberta
JORDAN C. MALLON , JONATHAN R. BURA, DIRK SCHUMANN, AND
PHILIP J. CURRIE

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7 minutes ago, rocket said:

 

Link goes to a very nice, but not maastrichtian paper, Temnospondyls from Keuper of germany :eyeroll:

this one

 

 

screwed that one, thanks, hopefully added the correct one, this time

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18 minutes ago, Troodon said:

Nothing has been published

 

That chart was not meant to be all inclusive and focused on Uzbekistans new Tyrannosauroid.

The following publication describes that specimen as a juvenile Albertosaurus

 

A Problematic Tyrannosaurid
(Dinosauria: Theropoda) Skeleton
and Its Implications for Tyrannosaurid Diversity in the Horseshoe Canyon Formation 2019 (Upper Cretaceous) of Alberta
JORDAN C. MALLON , JONATHAN R. BURA, DIRK SCHUMANN, AND
PHILIP J. CURRIE

 

@Troodon Thanks for the info! What do you think about the case of the taxonomic validity of "Alamotyrannus"? 

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All I'll say is that a Tyrannosaurid is present in the Ojo Alamo Fm,  like I showed in my Tyrannosaurid listing.  Only fragmentary material has been found and I believe unpublished, might be wrong.  I'll leave it up to the paleontologists to duke it out make that call when they are ready.    

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  • 3 months later...

Also here are some more additions to Maastrichtian Tyrannosauridae genera from Western and Eastern North America:

 

Mexico Maastrichtian Tyrannosauridae

Cf. Albertosaurus sp. (Tyrannosauridae, Locality 25 and 27 of Lomas Coloradas Formation of Naco-Cananea Sonara, Mexico, Maastrichtian Cretaceous (72.0-66.0 Million years ago))
(Based on Specimens Uncategorized vertebrate (ERNO) and tooth ERNO (IRGNM) 210)

 

Unnamed Tyrannosauridae genera (Tyrannosauridae, SON-11 of Cabullona Group of Naco-Cananea Sonara, Mexico, Late Campanian-Maastrichtian Cretaceous (72.0-66.0 Million years ago))
(Based on Specimens Uncategorized 12 teeth (ERNO))

 

 

Serrano-Brañas, Claudia & Gutiérrez-Blando, Cirene & Bigurra, Rubén & González-León, Carlos. (2017). First occurrence of tyrannosaurid theropods from the Corral de Enmedio Formation (Upper Cretaceous) Sonora, México. Cretaceous Research. 75. 10.1016/j.cretres.2017.03.015.

https://www.researchgate.net/publication/315470287_First_occurrence_of_tyrannosaurid_theropods_from_the_Corral_de_Enmedio_Formation_Upper_Cretaceous_Sonora_Mexico


Ramírez Velasco, Angel & Hernandez Rivera, Rene. (2015). Diversity of late cretaceous dinosaurs from Mexico. Boletín Geológico y Minero. 126. 63-108.

https://www.researchgate.net/publication/278018238_Diversity_of_late_cretaceous_dinosaurs_from_Mexico


Ramírez-Velasco, A.A., Benammi, M., Prieto-Márquez, A., Alvarado-Ortega, J. and Hernández-Rivera, R. (2012). Huehuecanauhtlus tiquichensis, a new hadrosauroid dinosaur (Ornithischia: Ornithopoda) from the Santonian (Late  Cretaceous) of Michoacán, Mexico.
Canadian Journal of Earth Sciences, 49, 1–18.
 

 

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