Is Nanotyrannus A Separate Species Or Is It A Juvenile T Rex?

[hxmendoza]

And to play devils advocate, what's to say the DD tyrannosaur is possibly a male. Bakker himself thinks the arms of T. rex were used in mating. To stimulate the female. Maybe males had proportionately longer and bigger manus elements than the females. No study has been done on this because of the very few arm and manus elements found throughout the Tyrannosaurids. Thomas Holtz and I have had this very discussion.

In terms of science, what is needed is a defacto male adult T. rex to be found and identified as such that has longer arms than defacto females. What if that is eventually found? What would that then mean for the DD Tyrannosaur?

Lots to be done and found and described still before the Dueling Dinosaurs Trumps everything.

I lean towards the validity of Nano for now based on those arms. But Hotlz is correct in my discussion with him about negative evidence and allometry.

Oh and one more thing. The Digit I claw found with Sue is missing it's tip. So there can be no definitive assessment as to its proper length given as Pete Larson has. He's a friend of mine. I respect him. But outright definitive comments like that are not supported.

Below is Sue's Digit I manus claw:

Edited February 17, 2016 by hxmendoza

[hxmendoza]

Agree they are bigger. I held an adult nanotyrannus hand claw today in the ballroom of the show and it was huge when I compared it to Stan's (big adult rex). Very different morphology. I did take a picture of the claw and will post it when I get back on my computer

Troodon I made my Stan comment on the assumption you meant that the cast claw you posted a picture of was from Stan based on the prior comment. It wasn't very clearly differentiated between those successive posts. So I misunderstood that, sorry.

But, as I said, no hand claws were found with Stan. The claws seen on all of the mounts are sculpted representations, per Neal Larson and personal observation.

Also, I strongly disagree. Comparisons can very well, and indeed be made, with the Campanian claws because, as can be quite easily seen, they all tend to follow the same morphological pattern. I've discussed this with Paleontologists at my Museum as well as other Tyrannosaur experts and they agree with my assessment and comparisons.

Edited February 17, 2016 by hxmendoza

[TheClawGuy]

Hxmendoza, that is very valuable information. It's great to have someone with your knowledge on the forum.

Troodon, because this is such at hotly debated topic, I agree that your claw can only be labeled as a Tyrannosaurid sp. indeterminate claw until more supporting evidence is found. Your hand claw could go either way at this point with the facts hxmendoza presented.

I think hxmendoza deserves one of those forum awards! Haha

[hxmendoza]

I've been trying to find out if Stan and Sue have both arm claws preserved. Before I use Bloody Mary's claws as a comparison, I must first make sure there's a T-Rex that has both hand claws preserved.

It seems that Stan wasn't found with his hand, and Sue was missing a hand claw.

stan__n_sue_comparison_by_scotthartman-d5yvql0.jpg

Andy, The claws on that Stan arm are sculpted claws. The claws on that photo of Sue's arm are also both sculpted. Both those arms are on display at BHI. The Sue arm was molded for display prior to Sue going to the Field Museum. The illustrated hand claw associated with Sue in Brochu's monograph was not available at that time when BHI molded and cast their displayed Sue arm.

Commercial collector Charlie McGovern went looking through the the Sue site with permission from the landowner after Sue's excavation. He found the proximal portion of the claw that I posted in prior post above. He molded it and later donated it to the Field Museum to go in her rightful place next in the Sue mount.

This is why the claws don't look much different in the photos of the hand posted by Troodon, since they're both conjectural (at the time) sculpts.

Digit I and II claws are quite different as I've shown above. And the Dueling Dinosaurs Tyrannosaur follows the same morphological pattern.

The Hell Creek specimen Petey (photos posted earlier by me above) show the difference even for the Hell Creek Tyrannosaurs.

As an aside. The Denver Museum of Nature and Science has a cast copy of Sue's claw (as do I) they restored the tip properly to what would be the correct length when proportionately compared to other know Tyrannosaurid D-I claws. It is easily 5+ inches along the curve. Charlie's restored tip version was also 5 inches along the curve. His tip was just not as curved or sharp as it should have been.

Edited February 18, 2016 by hxmendoza

[-Andy-]

Andy, The claws on that Stan arm are sculpted claws. The claws on that photo of Sue's arm are also both sculpted. Both those arms are on display at BHI. The Sue arm was molded for display prior to Sue going to the Field Museum. The illustrated hand claw associated with Sue in Brochu's monograph was not available at that time when BHI molded and cast their displayed Sue arm.

Commercial collector Charlie McGovern went looking through the the Sue site with permission from the landowner after Sue's excavation. He found the proximal portion of the claw that I posted in prior post above. He molded it and later donated it to the Field Museum to go in her rightful place next in the Sue mount.

This is why the claws don't look much different in the photos of the hand posted by Troodon, since they're both conjectural (at the time) sculpts.

Digit I and II claws are quite different as I've shown above. And the Dueling Dinosaurs Tyrannosaur follows the same morphological pattern.

The Hell Creek specimen Petey (photos posted earlier by me above) show the difference even for the Hell Creek Tyrannosaurs.

As an aside. The Denver Museum of Nature and Science has a cast copy of Sue's claw (as do I) they restored the tip properly to what would be the correct length when proportionately compared to other know Tyrannosaurid D-I claws. It is easily 5+ inches along the curve. Charlie's restored tip version was also 5 inches along the curve. His tip was just not as curved or sharp as it should have been.

Oh man, I gotta visit BHI one day!

Thank you for your contributions to this thread, hxmendoza.

Anyway, here's a measurement scale for Bloody Mary's arm.

[Killclaw]

Interesting to see the

Oh man, I gotta visit BHI one day!

Thank you for your contributions to this thread, hxmendoza.

Anyway, here's a measurement scale for Bloody Mary's arm.

Interesting to see the juxtaposition of those 2 images. It looks in fact like, in this example at least, the arm bones are actually a little longer and a lot more robust in the adult T-Rex but the phalanges in the fingers and especially the claws are completely out of proportion.

The rex hand claws and casts I've seen seem to vary from about 3 and a quarter inches to 5 inches or so so it would be interesting to know what Bloody Mary's does measure. Has there even been a guesstimate on this?

[hxmendoza]

I accidentally mislabeled the last picture above as Tarbosaurus manus digit II. It should be Digit manus I.

[doushantuo]

http://onlinelibrary.wiley.com/doi/10.1002/ar.20983/pdf

https://peerj.com/preprints/852.pdf

http://www.ohio.edu/people/witmerl/Downloads/2010_Witmer_&_Ridgely_Cleveland_tyrannosaur.pdf

Edited July 10, 2016 by doushantuo

[doushantuo]

http://rspb.royalsocietypublishing.org/content/royprsb/278/1718/2682.full.pdf

https://www.researchgate.net/publication/299602802_Dentary_groove_morphology_does_not_distinguish_'Nanotyrannus'_as_a_valid_taxon_of_tyrannosauroid_dinosaur_Comment_on_Distribution_of_the_dentary_groove_of_theropod_dinosaurs_Implications_for_theropod_

Edited July 10, 2016 by doushantuo