Khouribga Crocodiles

[Jurassicz1]

I found these crocodile teeth from Khouribga, Morocco, Phosphate Beds.

 

But not any info about the age. The Khouribga phosphates is Upper Cretaceous-Eocene. 

 

Anyone that knows the possible age?

There are some crocodile teeth & a jaw. Are they also real without any restoration? I thought about buying them. Or should I pass?

[DatFossilBoy]

Nice stuff! 
The age would be Cretaceous, and all the pieces are genuine without restoration. 
If the price is right, buy without concern.

Kind regards.

Edited January 26, 2022 by DatFossilBoy

[pachy-pleuro-whatnot-odon]

While a Cretaceous (Cenomanian) age would be correct if the teeth would've come from the Kem kem Group, the preservation of these teeth indicates they derive from the phosphate deposits. Here, crocodile date to the Early Eocene (Ypresian).

 

Thomas is right though in that the specimens are authentic without evidence of tempering. The first two appear dyrosaurid (see here for a discussion on species), whereas the rest looks like Maroccosuchus zennaroi. I'm not sure toothless crocodile jaw can be diagnosed to species...

[Jurassicz1]

13 hours ago, pachy-pleuro-whatnot-odon said:

While a Cretaceous (Cenomanian) age would be correct if the teeth would've come from the Kem kem Group, the preservation of these teeth indicates they derive from the phosphate deposits. Here, crocodile date to the Early Eocene (Ypresian).

 

Thomas is right though in that the specimens are authentic without evidence of tempering. The first two appear dyrosaurid (see here for a discussion on species), whereas the rest looks like Maroccosuchus zennaroi. I'm not sure toothless crocodile jaw can be diagnosed to species...

Alright thanks! But why does the crocodiles date to the Ypresian in the phosphates?

[Jurassicz1]

17 hours ago, DatFossilBoy said:

Nice stuff! 
The age would be Cretaceous, and all the pieces are genuine without restoration. 
If the price is right, buy without concern.

Kind regards.

Thanks! And yes they are very nice

[pachy-pleuro-whatnot-odon]

27 minutes ago, Jurassicz1 said:

Alright thanks! But why does the crocodiles date to the Ypresian in the phosphates?

 

Prior to that time the deposits in this area are marine, with no crocodiles known from its faunal assemblage. In fact, true marine crocodiles - thalattosuchia - had already long gone extinct by then. The aforementioned crocodilians are therefore also not marine crocodiles, but would likely have lived in a deltaic wetland environment...

[Jurassicz1]

2 hours ago, pachy-pleuro-whatnot-odon said:

 

Prior to that time the deposits in this area are marine, with no crocodiles known from its faunal assemblage. In fact, true marine crocodiles - thalattosuchia - had already long gone extinct by then. The aforementioned crocodilians are therefore also not marine crocodiles, but would likely have lived in a deltaic wetland environment...

So the ypresian deposits are not marine? Thanks for the response!

[pachy-pleuro-whatnot-odon]

6 minutes ago, Jurassicz1 said:

So the ypresian deposits are not marine? Thanks for the response!

 

Correct

[DatFossilBoy]

My mistake, thanks @pachy-pleuro-whatnot-odon for correcting me, I had based my judgment on some pictures I saw of Khouribga croc teeth that were misidentified as being Cretaceous instead of Eocene.

Kind regards.

[Jurassicz1]

21 hours ago, pachy-pleuro-whatnot-odon said:

 

Correct

Ok, if it's not a marine setting, what about the sharks? Like Otodus? Was there an ocean nearby?

[pachy-pleuro-whatnot-odon]

As said, the environment at the time would've probably been a deltaic or estuarian environment, possibly somewhat like a mangrove forest. As sharks are not unknown to swim up brackish waterways, this could easily have been the case here as well. So, yes, the ocean was likely still nearby, much in the same way that in the Maastrichtian land can't have been very far off to judge by the rare dinosaur fossils of Chenanisaurus barbaricus that have been recovered from the phosphate deposits of this time (see here for a similar discussion on the palaeoenvironmental reconstruction of the deposits of the Kem Kem Group).

[Jurassicz1]

On 1/28/2022 at 2:19 PM, pachy-pleuro-whatnot-odon said:

As said, the environment at the time would've probably been a deltaic or estuarian environment, possibly somewhat like a mangrove forest. As sharks are not unknown to swim up brackish waterways, this could easily have been the case here as well. So, yes, the ocean was likely still nearby, much in the same way that in the Maastrichtian land can't have been very far off to judge by the rare dinosaur fossils of Chenanisaurus barbaricus that have been recovered from the phosphate deposits of this time (see here for a similar discussion on the palaeoenvironmental reconstruction of the deposits of the Kem Kem Group).

Alright cool, Thanks. But I found these two for sale also (I'm collecting the phosphates) a enchodus palatine bone? And a pristis which is some kind of sawfish? Is it complete? It says it's Ypresian in age. 

 

[pachy-pleuro-whatnot-odon]

Fish aren't really my thing, but at first glance I'd say you're right.

[Jurassicz1]

38 minutes ago, pachy-pleuro-whatnot-odon said:

Fish aren't really my thing, but at first glance I'd say you're right.

Alright thanks!

[Anomotodon]

 

On 1/28/2022 at 7:19 AM, pachy-pleuro-whatnot-odon said:

As said, the environment at the time would've probably been a deltaic or estuarian environment, possibly somewhat like a mangrove forest. As sharks are not unknown to swim up brackish waterways, this could easily have been the case here as well. So, yes, the ocean was likely still nearby, much in the same way that in the Maastrichtian land can't have been very far off to judge by the rare dinosaur fossils of Chenanisaurus barbaricus that have been recovered from the phosphate deposits of this time (see here for a similar discussion on the palaeoenvironmental reconstruction of the deposits of the Kem Kem Group).

 

Do you have any references for the environment in Ypresian phosphates? To my knowledge, deposits in Khouribga range from Maastrichtian (Latest Cretaceous) to Ypresian (Early Eocene), including various Paleocene strata as well - see Bardet et al., 2012. There were some freshwater dyrosaurids around, but most were marine. Additionally, the abundance of large macrocarnivorous sharks like Otodus also makes it unlikely for the environment to be brackish. And, remains of terrestrial mammals abundant in contemporary Egyptian deposits, are just as rare in the Eocene of Khouribga as dinosaurian material is in the Cretaceous.

 

Quote

In general, dyrosaurids have been reconstructed as being shallow, near-shore marine animals utilizing axial swimming, typical of extant crocodylia, with perhaps greater tail undulatory frequency and more powerful forward thrust generated by expanded muscles of the tail (Hastings et al., 2011)

 

Anyways, several of these teeth are Dyrosaurid. They were present in the entire sequence of strata in the Khouribga basin - Cretaceous (Ocepesuchus), Paleocene (Atlantosuchus, Chenanisuchus, Arambourgisuchus) and Eocene (Dyrosaurus). Unless there are associated fossils (many micro-shark taxa could help with age determination) or the seller of your specimens knows the precise stratigraphy of the area, any age determination is speculative. Most specimens from this area don't have great provenance, so age assignment could only be done definitively for easily recognizable specimens (e.g., mosasaurs/plesiosaurs/pterosaurs/dinosaurs would be Maastrichtian, Otodus obliquus and Pristis would be Eocene, Paleocarcharodon would be Paleocene).

 

As for your teeth, a while ago I compiled this brief overview of different Dyrosaurid crocodile species from Morocco (there are a lot). Dyrosaurids are some of the more common crocs in those deposits, although there were some other groups too that are not as well researched.

 

 

Here is what I think about your teeth (references in the cited post)

 

left to right - Arambourgisuchus khouribgaensis (no striae on either sides); ?Dyrosaurus sp. (Dyrosaurus phosphaticus had striae on both sides, this tooth doesn't - could be a different species of Dyrosaurus, positional variation or even Atlantosuchus whose teeth are poorly described); Dyrosauridae indet. posterior tooth (based on compression and well-developed carinae I would assign this tooth to this family, but posteriors are not very diagnostic)

 

 

Sadly, can't say anything about these. They could be from Chenanisuchus, a dyrosaurid with unusually robust teeth, or one of the other non-dyrosaurid crocodiles, like Maroccosuchus

 

Edited January 30, 2022 by Anomotodon

[pachy-pleuro-whatnot-odon]

Well, I guess that, in that case, I stand corrected, as I do not have a reference to cite and it seems I've based myself on outdated information and wrong assumptions... For one, I wasn't aware dyrosaurids had been recovered from Cretaceous-age deposits as well. For another I assumed that the near shore behaviour of the dyrosaurids and other locality occurring crocodiles could be modeled in analog to the currently still living saltwater crocodile, a species that is just as much at home in the open ocean as in brackish and freshwater environments. I then took the fact that a great deal of near shore species are found together in the same area at relatively high frequency as an indication for shallower marine deposits, since it has elsewhere been observed that increasing ocean depth negatively influences the find frequency for pelagic vertebrates (with the same holding true, I believe, for benthic species). Moreover, one would expect less near shore species in the open ocean than closer to shore anyway. I therefore supposed a marine regression, bringing the area closer to the shoreline, if not it forming the actual shore itself. And while the occurrence of Otodus-sharks does, in my opinion, not prevent such an environmental reconstruction (I believe certain megalodon shark nurseries have been retrieved from palaeoenvironments that have been reconstructed as areas of brackish water, for example), it is, of course, true that when one takes the actual sediment in which these remains are found into account, the microvertebrate assemblage much rather points to a marine environment. With my limited knowledge of palaeoenvironmental reconstruction from sedimentation processes, this doesn't necessarily seem to rule out lagoonal or estuarian reconstructions for the post-Maastrichtian phosphate deposits, but it does rule out deltaic, and I should probably have realised it even more points towards a shallow shelf marine environment.

 

Actually, Tim, seeing as I keep discovering your knowledge of the crocodilian faunas of the phosphates and post-Maastrichtian palaeoenvironment there is so vastly more expansive than is mine, I probably should get the hint by now that next time it'll be safer for me to just defer the question straight to you 

[Anomotodon]

On 1/30/2022 at 3:39 AM, pachy-pleuro-whatnot-odon said:

Actually, Tim, seeing as I keep discovering your knowledge of the crocodilian faunas of the phosphates and post-Maastrichtian palaeoenvironment there is so vastly more expansive than is mine, I probably should get the hint by now that next time it'll be safer for me to just defer the question straight to you 

 

I am not very well-versed in paleoenvironments or sedimentary geology in general, just read papers sometimes haha. I do love crocodiles though, especially in the Cretaceous when there was so much diversity.

[pachy-pleuro-whatnot-odon]

4 hours ago, Anomotodon said:

I am not very well-versed in paleoenvironments or sedimentary geology in general, just read papers sometimes haha. I do love crocodiles though, especially in the Cretaceous when there was so much diversity.

 

Well, that reading is one you've got over on me then Haven't really had time to do so since my wife got pregnant of our daughter... Have tons of articles lined up that I wish I had to the time to read, but the combination of baby and Covid has made that pretty much impossible So, as I said, outdated knowledge