How to distinguish crocodiles?

[Hyaena]

Hello, I have a question about the identification of crocodiles.
The first series of photographs, the top row are teeth belonging to Sphiraendus, and the bottom row are crocodiles, they have a cutting edge! (White tooth is a modern Nile crocodile from the zoo)
Then the suspicious jaw...
This is followed by a series of photographs where the top row belongs to Eutrichiurides sp, but the bottom row is a question. The degree of preservation and enamel is completely different.
We continue further.
Fragment of bone and part of the skull. The bone definitely belongs to the Eocene era (certainly not the Pleistocene or Miocene). Part of the skull perhaps a large fish?
And finally, an armored shield, it is heavily rounded and the relief from one of the halves has disappeared. To be honest, I think it's more likely from Acipenseridae than from the shield of a crocodile, but suddenly someone recognizes it.
Location, Russia, Ural, Derney stream. Age Eocene, Barton-Priabonian.

Edited June 5, 2022 by Hyaena

[pachy-pleuro-whatnot-odon]

Hi there, and welcome to TFF. Nice finds! I especially like the teeth and jaw

 

I'm just somewhat confused as to your precise question. Concerning the teeth: are you asking for species, whether the separation you made is correct, or how to, in general, identify crocodile teeth as such? For, in general terms, crocodile teeth have two carinae, placed perfectly along the line the of the jaw (i.e. mesially and distally); curve inwards (i.e., perpendicular to the mesiodistal line along which the carinae are located; labiolingual curvature over the full crown height); are often striated, with densely packed striae running in and terminating at the carinae; have crowns with deep and wide concavities at their base. These latter features would be way less pronounced or even absent in fish teeth, which are typically connected directly to the jaw and, moreover, are tipped with an acrodin cap. Thus, while I haven't been able to look up what kind of animal Sphiraendus is, let alone what kind of teeth it has, all of the photographed teeth from the first batch would superficially seem a good match for crocodile. Better photographs of each individual tooth would be needed to confirm this. Also, it's not likely that you'll get to either species or genus level identification, unless you'd be willing and able to provide site information and/or a list of locally occurring palaeobiota. In any case, the below thread my be useful in furthering your understanding of how to identify crocodile teeth:

 

 

As a side note, please also keep in mind that crocodilian teeth may become button-shaped (vertically compressed) and more durophagous in nature towards the back of the jaw.

 

As concerns your second set of teeth, I'd agree that the top row definitely consists of fish teeth with their smooth enamel surfaces and acrodin caps, and that these teeth appear to match what I've been able to find for Eutrichiurides sp.. And while I don't quite know why the preservation of the bottom row of teeth is so different from that of the top row (could it be these teeth from the bottom row were eaten and have gone through the digestive track of some animal?), they do seem to be fish teeth as well, lacking, for instance, the hollow base seen in the crocodile teeth. Moreover, the right-most specimen from this row seems to have the exact same shape, very similar preservation, and even remnants of an acrodin cap, making it visually very similar to the left-most specimen from the top row. I'd thus suggest it's an Eutrichiurides sp. as well. In contrast, the left-most tooth from the bottom row reminds me of Enchodus in terms of its ornamentation and how tall it is. If so, the others may possibly also be Enchodus. But I'm far from experienced with fish teeth, so you're likely going to get better results once one of our fish specialists finds their way to this thread...

 

When it comes to the jaw, all I can really say is that it has thecodont dentition, and may therefore be a match for crocodile, although the foramina so typical for the jaws of this clade are nowhere to be seen on either side of the jaw. Just for the sake of this being an aquatic environment, and not knowing whether it's a marine or freshwater one, I think we can also exclude toothed whale, as those would have alveoli positioned such as to clearly direct the teeth outward, which is not the case here. I think we can also further exclude terrestrial animals and mammals, so that leaves aquatic reptile, e.g. crocodile, as far as I'm concerned.

 

Then your final piece: I don't really see any patterns left on the specimen. But even if those would've worn off, the piece looks too thick and not uniformly flat enough to be a crocodile scute, as far as I'm concerned.

 

The rest I can't really help you with, but now that the discussion has been started, hopefully someone will come along and pick up where I left off One such a person who's well-versed with both fish remains and crocodile teeth, as well as with the type of preservation that your teeth have is @Anomotodon...

[Hyaena]

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

Hi there, and welcome to TFF. Nice finds! I especially like the teeth and jaw 

 

I'm just somewhat confused as to your precise question.

Thank you very much for such a detailed answer. I have indeed missed a number of questions clarifying what I want. English is not my native language and I am somewhat carried away by writing the text) I tend to agree with you about identification! Especially in the photo with Eutrichiurides. For photos from Spiraendus, I relied on the site http://www.dmap.co.uk/fossils/ The faunistic complex itself is approximately the same as in Europe, only changes in the composition of mollusks. I'll take a closer look at the topic you suggested. It's still about learning crocodile teeth from others.

[pachy-pleuro-whatnot-odon]

No worries, always glad to help

 

And about the language: as someone who speaks multiple languages, some less than perfectly, I know how difficult it can be to express yourself in a language that's not your own. Even so, your English is very good

 

12 minutes ago, Hyaena said:

For photos from Spiraendus, I relied on the site http://www.dmap.co.uk/fossils/

 

I had a look at the website you referred to see if I could find something about Spiraendus, but can't find anything, not even when searching the site with Google. May be you have a direct link? You can also consider posting pictures from that site here on the forum to enrich the forum's knowledge base - as long as you refer to the place you got the photographs from this should be okay (just don't link to vendor sites )...

 

16 minutes ago, Hyaena said:

It's still about learning crocodile teeth from others.

 

I think that should be a very achievable goal, since I presume fish teeth are the only other contenders. As said, there any various elements that set crocodile teeth apart, including the carinae, labiolingual compression, curvature, striations and acrodin cap. That having been said, convergent evolution has ensured that some fish species are very difficult to distinguish from reptiles. Have a look at the below post and thread for examples

 

 

 

[Hyaena]

Good day!
It confuses me that the top row does not have cutting edges, while the bottom ones do. On this basis, he divided the teeth into two groups.
Here is a link to the Sphyraenodus section. And this ribbing at the base of the crown is embarrassing.
I repeat that the complex is very similar to ours as a whole. But for us it was already a drying-closing strait or bay on the outskirts of the ocean at that time.

 

https://www.dmap.co.uk/fossils/barton/vert/bartvert.htm
javascript:DisplayImage('Sphyraenodus sp.','','','Teeth from a Barracuda-like fish in the Mackerel Family (Scombridae)) (coll. Alan Morton','sphy1.jpg','5.0',329,395,'Middle Barton Beds - Barton-Highcliffe','10mm','Scombridae')

[pachy-pleuro-whatnot-odon]

7 hours ago, Hyaena said:

It confuses me that the top row does not have cutting edges, while the bottom ones do. On this basis, he divided the teeth into two groups. [...] And this ribbing at the base of the crown is embarrassing.

 

Good point, and hard to judge from a photograph: with the level of preservation of these teeth it's certainly imaginable that any past carinae present could've worn off (as happens with a number of reworked Dakosaurus-teeth found at Faringdon). Striations on crocodilian teeth may also not reach the full apicobasal height of a tooth, though they mostly do. However, on renewed inspection, it seems like the dental cavity of these top teeth, with the exception of the second from left, is very shallow to non-existent - which would point to them indeed being fish teeth...

 

8 hours ago, Hyaena said:

Here is a link to the Sphyraenodus section.

 

Thanks! I think I probably couldn't find them because I didn't have the name correctly. I had also not heard the name of this fish before, so that certainly didn't help (apparently, it's a barracuda-like fish in the mackerel family Scombridae). However, I've done a bit of searching and came up with the following sample for comparison:

 

Sphyraenodus sp., 10mm, Middle Barton Beds - Barton-Highcliffe, Bartonian-stage of the Middle Eocene (source)

 

 

Sphyraenodus sp. from Derney, Sverdlovsk region, Russia (source)

 

 

Sphyraenodus sp. from the Eocene of Kiev in @Anomotodon's collection (source)

 

 

Sphyraenodus sp. from an unknown locality (in Essex?) and of unknown age, in @clactonbloke's collection (source)

 

 

Based on this material, I'd say you're probably right in that the top row of the first set of teeth does look like Sphyraenodus sp., both in terms of their overall conical shape with smooth enamel, but the left-most tooth appears to have the same enamel-folds as do Sphyraenodus spp. teeth. Not only that, but the latter appear to have a dental cavity, much like reptile teeth, as well, and lack an acrodin cap, which means that, in this case, the absence of carinae and, above all, the enamel folds can, in addition to the general conical shape of these teeth, be used as identifying characteristics.

 

 

Interestingly, while doing the above investigation, I bumped into the below teeth, also from the Scombridae-family, that, for their ornamentation, might be a better match for the bottom row of teeth of the second set than my proposed Enchodus.

 

Ardiodus mariotti, Oldhaven Beds, Upnor, Kent; scale bar=5 mm (fig. 37 from Monsch, 2004)

 

You really want somebody more versed in fish teeth for this, though, and preferably someone who's also familiar with the time-period. Possibly @will stevenson can help out...

[Notidanodon]

I think you’ve pretty much got this one covered @pachy-pleuro-whatnot-odon isolated fish teeth are tricky to identify

something to add is the circled one also looks likeEutrichiurides to me

[pachy-pleuro-whatnot-odon]

35 minutes ago, will stevenson said:

something to add is the circled one also looks likeEutrichiurides to me

 

Yup, me too

[Hyaena]

Thank you very much! By the way, thanks to the image of Ardiodus, I identified part of the teeth from the still undisassembled. We have many of these.
About the site from where the images are also Derney and Kyiv. I regularly go on paleo excursions with one of these people, and in particular, we wanted to figure it out and clarify by asking the international community, and not just "boil in our own boiler".
I also know a man from Kyiv and his collection, unfortunately, due to the current monstrous situation, I do not have enough moral strength to write to him, and I think he is not up to it now. I'm sorry I have no words....

[pachy-pleuro-whatnot-odon]

18 hours ago, Hyaena said:

I also know a man from Kyiv and his collection, unfortunately, due to the current monstrous situation, I do not have enough moral strength to write to him, and I think he is not up to it now. I'm sorry I have no words....

 

There are no words to describe the horrors that are going on in Ukraine right now. And I can totally imagine how this has disrupted friendships, even family relationships. Let's just hope that somehow this will all come to an end soon, and that, in the aftermath, it'll be possible to restore at least these individual and personal relationships...

[Morte]

On 6/5/2022 at 8:54 PM, pachy-pleuro-whatnot-odon said:

I'm just somewhat confused as to your precise question. Concerning the teeth: are you asking for species, whether the separation you made is correct, or how to, in general, identify crocodile teeth as such? For, in general terms, crocodile teeth have two carinae, placed perfectly along the line the of the jaw (i.e. mesially and distally); curve inwards (i.e., perpendicular to the mesiodistal line along which the carinae are located; labiolingual curvature over the full crown height); are often striated, with densely packed striae running in and terminating at the carinae; have crowns with deep and wide concavities at their base. These latter features would be way less pronounced or even absent in fish teeth, which are typically connected directly to the jaw and, moreover, are tipped with an acrodin cap. Thus, while I haven't been able to look up what kind of animal Sphiraendus is, let alone what kind of teeth it has, all of the photographed teeth from the first batch would superficially seem a good match for crocodile. Better photographs of each individual tooth would be needed to confirm this. Also, it's not likely that you'll get to either species or genus level identification, unless you'd be willing and able to provide site information and/or a list of locally occurring palaeobiota.

Hello there)) I've read all this topic, and just for more clear understanding: a two perfectly cutting edges or carinae and round concavity in tooth's base, could be a distinctive features of the crocodile teeth, right? So, this is gonna be a crocodile tooth? I thought about Scomeromorus genus before, but theirs teeth are flattened and there is no any concavity in tooth's base. I have few more teeth, which hard to me for identification, and one of them even has a root. Would be perfect to know, what animals these teeth belongs to, and I'm almost 100% sure that is not a fish)) 

If anything - sorry for curve and hard English))

[pachy-pleuro-whatnot-odon]

On 6/8/2022 at 2:05 PM, Morte said:

Hello there)) I've read all this topic, and just for more clear understanding: a two perfectly cutting edges or carinae and round concavity in tooth's base, could be a distinctive features of the crocodile teeth, right? So, this is gonna be a crocodile tooth? I thought about Scomeromorus genus before, but theirs teeth are flattened and there is no any concavity in tooth's base. I have few more teeth, which hard to me for identification, and one of them even has a root. Would be perfect to know, what animals these teeth belongs to, and I'm almost 100% sure that is not a fish)) 

If anything - sorry for curve and hard English))

 

No worries, your English is just fine. And we're allowed to have threads drift away from their original topics on TFF as well, since you never know where you're going to end up 

 

Unfortunately, though, I'm probably not the right person to ask on how to differentiate fish teeth, as I normally deal with marine reptile material, which is where my strength lies, and have kinky recently started dabbling with fish teeth, more or less against my will (), as they can sometimes confuse the identification of marine reptile teeth. From what I've learned so far, however, most fish teeth don't have roots, so if your tooth does, there's a good chance its crocodilian. But only if the root is peg-shaped and smooth. Also, if the tooth has an acrodin cap, you can be sure it's a fish.

 

Coming to your two teeth, I'd say that the bottom one does indeed appear to be a clearly crocodilian tooth, as it has both carinae with pinched edges and a convex labial and lingual surface. The top tooth has a lot less to go on and seems more worn, but appears to confirm to the same general morphology as the bottom one. In any case, from a quick online search, Scomberomorus-teeth seem much more laterally compressed, with a prominent bulge central to the tooth. Compare to the below example (fig. 64) taken from Ebersole, Cicimurri and Stringer, 2019:

 

A-I: Palaeocybium proosti; J-R: Scomberomorus bleekeri; S-AA: Scomberomorus stormsi.

 

Hope this helps!