New Carcharodontosaurian from Uzbekistan

[Troodon]

A number of us have seen teeth that have a morphology somewhat similar to a Carcharodontosaurid from the Bissekty Formation of Uzbekistan but were not Tyrannosauroid.  This paper describes Ulughbegsaurus uzbekistanensis a new Carcharodontosaurian from that locality.   The holotype does not include teeth but my guess is that those with Carch morphology can be assigned (opinion changed below) to this new taxon until we see more published.  This taxon is not a Carcharodontosaurid and its classification appears to be uncertain depending on which phylogenetic analysis is used. 

 

https://royalsocietypublishing.org/doi/10.1098/rsos.210923

 

 

 

@-Andy- @hxmendoza @Runner64

[Troodon]

On Wikipedia the two classification analyses.   Additional specimens will be needed.

 

 

 

[Troodon]

Getting through the paper it makes comments on isolated teeth so CBR's to 0.41- 0.70 and CBL's up to 26.6 could belong to Carcharodontosurians

 

Although difficult to demonstrate unequivocally at present, it is possible that some isolated teeth from the Bissekty Formation are attributable to carcharodontosaurians, based on alveoli measurements as a proxy for tooth dimensions. The maxillary alveoli of the Ulughbegsaurus individual are relatively large with mesiodistal lengths ranging from 21 to 33 mm (mean 28.6 mm). Alveoli measured from a maxilla referable to Timurlengia are smaller (mesiodistal length: 19.3–21.7 mm, n = 3) than Ulughbegsaurus, as are those previously reported in a maxilla (largest is 19.5 mm) and dentary (largest is 22 mm in ZIN PH 15/16) referred to Timurlengia [19]. Also, Ulughbegsaurus tends to have relatively narrow alveoli (ratio of labiolingual width and mesiodistal length: 0.48–0.54, mean 0.51 mm) compared with those of Timurlengia (0.51–0.74, mean 0.64), consistent with carcharodontosaurians in general, which have significantly narrower teeth than tyrannosauroids (p < 0.01, see electronic supplementary material, figure S6). However, overlap in both alveolus length and ratio values are seen between Ulughbegsaurus and Timurlengia. Many of several large, isolated theropod teeth (crown base length: CBL > 15 mm) from the Bissekty Formation (at UzSGM), are narrow with crown base length to crown base width ratios (CBR) values (0.45–0.56, mean 0.50, n = 7) similar to the alveolus ratios of Ulughbegsaurus . With the largest alveoli of Timurlengia at a mesiodistal length of 22 mm, it is possible that some of the large tyrannosauroid teeth reported from Dzharakuduk of the Bissekty Formation (with CBLs up to 26.6 mm and CBR to 0.41–0.70 [13]) could belong to carcharodontosaurians.

[Runner64]

@Troodon enamel wrinkling on the mesial carinae is fairly prominent in Carchardontosauridae. Some more derived tyrannosauroids like T. rex have it as well but not as exaggerated. However, Timurlengia is much more basal. Do you think mesial enamel wrinkling could be useful for ID?

[Troodon]

After I read the paper I will pump the breaks and change my  comments from above and say Im not sure we can use Carcharodontosauridae characteristics at least not right now.  The paper suggested that isolated teeth may be a Carcharodontosaurian based on base size and ratio's but did not mention any Carcharodontosauridae characteristic to aid in the ID.  We really do not know what these teeth look like nor do we know if this taxon is a Neovenatoridae or something else but it does not appear to be a Carcharodontosauridae.   Features will be different depending on what family its in.  You can draw any conclusions you like but it would not be scientifically supported until we see these teeth described   

[Kikokuryu]

@Troodon The exact placement of Ulughbegsaurus aside, what exactly did people consider Carcharodontosauridae indet. from Bissekty to begin with? Enamel wrinkling? Denticle shape? Do you have an example of what to possibly look as a decent bet? Or has it always just been any big theropod that falls outside of Timurlengia.

 

I've never seen people talk about them except, I think one time I saw it somewhere while searching for information on Bissekty teeth.

 

I don't think I fully understood what the enamel wrinkling in Carcs was supposed to look like. But if I understand correctly, it's these sort of wavy patterns in the enamel right? I know alot of my KK Carcs have this, as well as this Bissekty tooth. If Timurlengia also has enamel wrinkling, then it's probably not a good indicator.

 

 

 

[Troodon]

Short marginal undulations (wrinkles) close to the carinae are a well known feature of carcharodontosaurid teeth.  So when it was seen on large Bissekty theropod teeth the question was raised do we have Carcharodontosaurids in that fauna.    Publications on Timurlengia teeth are few and there is no mention of undulations on the one that exist but they are a widespread feature on non-avian dinosaurs so we dont know for certain.   It may be reasonable to make the connection that undulations equate to a Carcharodontosaurid but we have a possible Neovenatorid or other family so without looking at other characteristics I think its premature to assign wrinkles as diagnostic to this new Taxon. 

Your tooth given the fine serrations, long narrow crown looks like a Timurlengia with marginal undulations.  My point...

 

Now couple undulations, denticle density/shape with CBL and CBR (as mentioned in the paper) you may have a way to get you to an assignment to Ulughbegsaurus.

[Kikokuryu]

This is probably something important to keep in mind going forward if you see supposed "Ulughbegsaurus" teeth for sale. I can only assume that any teeth with wrinkles will commonly end up being labeled as Ulughbegsaurus.

 

If marginal undulations alone are not a definitive indicator and probable Timurlengia teeth like the one I have do have wrinkles, then it will be easy mistake for someone to make, especially with small teeth.

[Flx]

"Comparison of the maxilla with that of other allosauroids indicates Ulughbegsaurus was 7.5–8 m in body length"

I am always amazed by statements like that.