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Spanish Spinosaurids it's Implication to Kem Kem's Spinosaurids


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I came across this paper in Fruitbat's library and it raised some questions so decided to see what others think.

 

The paper studied Spinosaurid teeth that were found on the Iberian peninsula La Cantalera site and concluded

that two morphotypes of spinosaurid teeth were recognized in the early Barremian of that site: both a Baryonychinae indet. and Spinosaurinae? indet.  They ruled out attribution to other theropods or crocodylomorphs, although they remained cautious due to the scarce fossil record known.  It also concluded that Spinosaurinae? indet. did not fit exactly with any of the described spinosaurine teeth, and regarded them as belonging to an unknown spinosaurine spinosaurid, probably closer to Spinosaurus than any other member of Spinosaurinae.  

 

So let's move forward in time to the Kem Kem.  Ute Richter 2012 research described 3 morph types in the Kem Kem distinguished from each other by ornamentation and concluded that more than one species may be present..    Teeth from this region are typically straight but thin curved ones do show up like the one posted by indominus rex (see pic below) and some are attributed to croc's.  So what if we had another morph type in this region a thin more curved tooth more like Suchomimus which is a Baryonychinae.  The Spanish teeth suggest that these two families might coexist in the same fauna.   I believe there are multiple species in the Kem Kem,  Sigilmassasaurus for sure and Spinosaurus sp. but are there additional ones more aligned with Baryonchinae?  Food for thought....

 

The Spanish teeth are described quite well: 

The mesial margin of the teeth is convex, while the distal margin is concave or straight. The cross-section varies between elliptical and subcircular.  All teeth have mesial and distal carinae, but some teeth do not have serration on the mesial carina. Carinae are located on the mesiodistal axis of the crown and start close to the cervix. Denticles are chisel-shaped and their height and width vary between 0.1 and 0.12mm. Denticle density per mm ranges from 6 to 12. The denticle size density index values are close to one, so there is no difference between the mesial and the distal size of the denticles. The denticles are perpendicular to the margin of the teeth. Both faces of the teeth bear enamel ornamentation which consists of 6–7 ridges (on average) orientated apicobasally; the ridges do not reach the apex.

 

 

 

https://www.researchgate.net/profile/Antonio_Alonso7/publication/276158392_On_the_spinosaurid_theropod_teeth_from_the_early_Barremian_Early_Cretaceous_Blesa_Formation_Spain/links/556c19a708aefcb861d619c9.pdf?origin=publication_detail

 

 

Screenshot_2017-12-07-03-51-57.thumb.jpg.d6b094e58ef789e6f9c0bdf9c2314c2e.jpgScreenshot_2017-12-07-03-52-21.thumb.jpg.ace0730129a257bce6253e3ecbd14dfe.jpgimage.thumb.jpeg.0415aceb691c1a61a95787994d671cdf.jpeg.be80cafdba01b47aae0356d0935c6c08.thumb.jpeg.f1639d6a41e9fc9570aa51db9484be26.jpeg

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Those are quite curved indeed. Though some from Kem Kem are also somewhat curved. Okay so two tooth morphotypes of Baryonchinae and Spinosaurinae in Spain. I'm wondering if we can apply the differences to the known teeth from the Kem Kem region as well. It is known from bone remains that Sigilmassasaurus seems to be more closely related to Baryonyx and Suchomimus than to Spinosaurus. So the same families seem to be present in Kem Kem.

Olof Moleman AKA Lord Trilobite

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Since so little is known anything is possible and two spinosaurid subfamilies in the Kem Kem is of course possible.  No smoking gun yet, we need a jaw with teeth identifiable to Sig or X.   I think I'm fairly comfortable saying that in addition to the tooth morphologies identified by Ute we have an a couple of variations in the overall shape of the tooth.  Even Ute's paper showed a one of those curved teeth but she did not comment on it.  I plan to pay extra attention at the Tucson show for these teeth and see if I can find any serrated versions.  

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The problem is that nice jaws, even partials ones are typically sold with composited teeth at stupid prices.  But you are correct I will keep an eye out for them 

 

Here are a couple from 2016 with all very straight teeth

20160126_101420.thumb.jpg.c2f1d87d5cf0318773007188bb9badc1.jpg

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Are those teeth all original? Or are they composited in? And I'm curious if those teeth have striations or that they are smooth. That dentary on the lower right looks very similar to the holotype of Spinosaurus aegyptiacus.

 

Very nice specimens btw.

Olof Moleman AKA Lord Trilobite

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Everything on the Spino jaws are composited meant to give the appearance of unerupted teeth.   This dealer is one of the best on Moroccan fossils.  I dont recall the price and my photo is not sharp enough to read the yellow tag but I think it's In the 4 figures.

He has a number of boxes like this where I could look for that thin curved morphology.  Nothing jumps out in that box.

20171207_135405.thumb.jpg.223f81d9a470fb1dd23c4dd5dddb0b86.jpg

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Serrations on Suchomimus.  Now if we can find anything like these from the Kem Kem it would be our smoking gun

 

graphic-3.large.thumb.jpg.9af134d0a7a15d144c3f12536575f467.jpg

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