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Are most spinosaurus teeth sigilmassasaurus teeth?

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Pterygotus

I was told by a friend that most spinosaurus teeth are sigilmassasaurus. Is this true? If so, does this make spinosaurus rare and sigilmassasaurus the common one? Sorry about my limited knowledge on these things.

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gigantoraptor

No skull material with teeth is found from either species so It's really just guesswork. I have a Spinosaurid indet. tooth that clearly is different from all other teeth I've seen. I hope maybe one day it will be clear what kind of teeth belong to what species but there is a chance it will never be possible.

 

There isn't a single kind of theropod tooth from the Kem Kem beds hat can be assigned to a specific genus. 

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Abstraktum

As others already stated you can't talk about species with single teeth. It is in general very difficult to distinguish the species, as there is so little material to work with. There is a January 2019 paper that covers this topic as well (as @TyBoy stated not everybody agrees on everything when it comes to Spino Material, so this here is just one scientific opinion)

 

CLICK

 

Quote

This conclusion is consistent with other studies of the Kem Kem assemblage; two spinosaurids appear to be present in the Kem Kem. Evers et al. (2015) recognized two distinct vertebral morphologies, which were identified as Sigilmassasaurus brevicollis(including Spinosaurus maroccanus) and Spinosauridae indet. The second spinosaurid vertebral morph, Spinosauridae indet., tends to be smaller than Sigilmassasaurus (Evers pers. comm. to NRL, 2018) and may represent the same taxon as the Spinosaurus neotype (Evers et al., 2015). Phylogenetic analysis has not been able to resolve the position of Sigilmassasaurus using the vertebrae alone, which are variably recovered either in a polytomy with other spinosaurids, or as part of Baryonychinae. However, phylogenetic analysis of quadrates from the Kem Kem indicates the existence of two species of spinosaurid, both referable to Spinosaurinae (Hendrickx et al., 2016). Two different morphotypes of rostrum are present as well. The larger rostrum morph has been referred to Spinosaurus cf. aegyptiacus (dal Sasso et al., 2005) but given its size, it may instead pertain to Sigilmassasaurus. A second, smaller spinosaurine rostrum morph (Cuff and Rayfield, 2013) is characterized by concave dorsal margin of the rostrum and a more bulbous premaxilla and overall more gracile proportions.

 

There are therefore two spinosaurines in the fauna on the basis of vertebrae, rostra, frontals, and quadrates. In the absence of associated material, it is difficult to be certain which material belongs to which taxon. However, on the basis of vertebrae, Sigilmassasaurus may have grown larger. If so, the large frontals described here and the giant rostrum (dal Sasso et al., 2005) would presumably belong to Sigilmassasaurus, and the other material, to the second spinosaur. Based on these inferences and assumptions, our phylogenetic analysis suggests that Sigilmassasaurus and Spinosaurus are distinct but closely related species within a subclade we term Spinosaurini. Accordingly, the composite reconstruction of Ibrahim et al. (2014) may well incorporate more than one species, but it probably provides a reasonably accurate picture of the body plan of a spinosaurin.

 

The relationship between the Spinosaurus neotype, FSAC-KK 1188 and the holotype, is unclear however. Solving this problem is beyond the scope of this paper, but it is worth noting that the neural spines of the holotype (Stromer, 1915a) are much more expanded than those of the neotype (Ibrahim et al., 2014). Given that the sail probably served a display function, these differences could easily result from ontogenetic change or sexual dimorphismin sail morphology. However, it is also possible that they are of taxonomic significance, in which case the neotype might conceivably represent a species other than the S. aegyptiacus holotype.

 

 

About the last part: 

The Holotype no longer exists, so you cant compare them. It was completely destroyed during a bomb raid on my Hometown in WWII. I mentioned this as well with some pictures in my topic about the Museum in Munich :)

 

http://www.thefossilforum.com/index.php?/topic/87289-museum-in-munich/

 

 

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fossil_sea_urchin

I am not sure if we can call morrocan Spinosaurs, Spinosaurus. The remains of several african dinosaurs were destroyed in the bombing raid, including Spinosaurus. So how do we know what Spinosaurus is?

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Abstraktum

Yes, as I understood it correctly, Spinosaurus maroccanus was described by Russell in 1996 in this paper CLICK

 

But it's questionable wether this is a correct description or not. For example this paper CLICK from 1998 states Spinosaurus maroccanus might be just Spinosaurus aegyptiacus.

Quote

Although the Moroccan and Algerian materials have been referred to a different species (S. maroccanus), its distinction from S. aegyptiacus (by the proportions of the centrum of an isolated cervical vertebra) and the basis for the referral of additional material are questionable. We regard S. maroccanus as a nomen dubium and provisionally refer all spinosaur material from Albian- and Cenomanian-age rocks in northern Africa to S. aegyptiacus.

 

Well I think you can find a scientific paper for any opinion on this matter, so as long as there is no new material dug up, we all label our Spino teeth from KemKem Spinosauridae indet. and wait patiently. :ninja:

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gigantoraptor
12 minutes ago, Abstraktum said:

Yes, as I understood it correctly, Spinosaurus maroccanus was described by Russell in 1996 in this paper CLICK

 

But it's questionable wether this is a correct description or not. For example this paper CLICK from 1998 states Spinosaurus maroccanus might be just Spinosaurus aegyptiacus.

 

Well I think you can find a scientific paper for any opinion on this matter, so as long as there is no new material dug up, we all label our Spino teeth from KemKem Spinosauridae indet. and wait patiently. :ninja:

I tought S. maroccanus is an nomen dubium? I think it's called Sigilmassasaurus brevicollis now.

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Abstraktum
2 minutes ago, gigantoraptor said:

I tought S. maroccanus is an nomen dubium? I think it's called Sigilmassasaurus brevicollis now.

 

As far as I know yes, for example here CLICK

Quote

We argue furthermore that Spinosaurus maroccanus, also described on the basis of isolated cervical vertebrae from the same stratigraphic unit and in the same paper as Sigilmassasaurus brevicollis, is a subjective synonym of the latter.

 

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TyBoy

The same can be said of teeth from the Carcharodontosaurids, Carcharodontosaurus and Sauroniops.    How many distinct species coexist in this fauna, is Sauroniops valid?  Will we be able to differentiate between teeth of these species?  More unknowns in the Kem Kem than knowns.  Keep collecting someday we may have answers.

 

Wouldn't be crazy if the second smaller Spinosaurid is a different genus than Spinosaurus.  Think of the ramifications?   Would dealers and collectors ever stop calling the teeth Spinosaurus?  Serious collectors would adopt the new name quickly but not the casual one.

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