Some dinosaur fossil ID

[Troodon]

Focusing on the first tooth, teeth of Megalosaurids are difficult to distinguish from those of Piatnitzkysaurids, but some differences exist - Hendrickx
The mesial denticles of Marshosaurus are slightly smaller than the distal serrations which is never the case in megalosaurids.  However since your tooth is missing the mesial carina we not have that feature to look at, as well as how far it extends to the cervix, makes a diagnose very difficult.  Your CBR is .41 which says its very compressed and Marshosaurus teeth are typically higher but you have the serration density that fits.  Without a more complete tooth don't an answer since the CBR fits a Ceratosaurus in compression but the other features lean me more toward cf Marshosaurus.   

[Troodon]

On the second tooth can you take a base length and width measurement.   Your best call on density is 4/mm on the distal side how about the mesial?   Are there any blood grooves alongside the denticles?

[Anomotodon]

2 hours ago, Troodon said:

On the second tooth can you take a base length and width measurement.   Your best call on density is 4/mm on the distal side how about the mesial?   Are there any blood grooves alongside the denticles?

Thank you!!,

So, do you think that Piatnyzkisauridae indet. (until Portuguese "Marshosaurus" will be described) will be an accurate ID for both specimens?

For the first one, I think actual CBR will be smaller (around 0.35) since tip is incomplete.

For the second one, mesial density seems to be around 6-7/mm. Don't see any blood grooves.

[Troodon]

38 minutes ago, Anomotodon said:

Thank you!!,

So, do you think that Piatnyzkisauridae indet. (until Portuguese "Marshosaurus" will be described) will be an accurate ID for both specimens?

For the first one, I think actual CBR will be smaller (around 0.35) since tip is incomplete.

For the second one, mesial density seems to be around 6-7/mm. Don't see any blood grooves.

CBR is base ratio nothing to do with tip, looks at compression at base.  Piatnyzkisauridae indet looks reasonable but not definitive because of the missing mesial carina.

The second tooth cannot be  that dense 6-7/mm are you sure.  Distal? What about base width and length.

[Anomotodon]

11 minutes ago, Troodon said:

CBR is base ratio nothing to do with tip, looks at compression at base.  Piatnyzkisauridae indet looks reasonable but not definitive because of the missing mesial carina.

The second one is that dense 6-7/mm are you sure.  

Oh, I mistook CBR for CHR and gave you numbers for total crown length and crown base length. I will tell the exact number once I get home, but I think width is around 4-5 mm.

Well, according to the picture it is 7 mm, though regarding potentially slightly wrong angles it could be 5-6/mm but still definitely finer than distal.

[Troodon]

27 minutes ago, Anomotodon said:

Oh, I mistook CBR for CHR and gave you numbers for total crown length and crown base length. I will tell the exact number once I get home, but I think width is around 4-5 mm.

Well, according to the picture it is 7 mm, though regarding potentially slightly wrong angles it could be 5-6/mm but still definitely finer than distal.

Go ahead and check the numbers.  Not sure whats in that fauna with 7/mm thats pretty dense.  My guess closer to 5.  And need the distal

[Anomotodon]

On 3/2/2018 at 3:13 PM, Troodon said:

Go ahead and check the numbers.  Not sure whats in that fauna with 7/mm thats pretty dense.  My guess closer to 5.  And need the distal

 

Calculated densities again for the entire carinae: mesial - 5.5/mm, distal - 4/mm for tooth 2. CBR for tooth 1 is 0.45, tooth 2 - 0.56.

[Haravex]

sorry to ask this but for all of us less informed what does CBR and CHR stand for?

[Anomotodon]

1 minute ago, Haravex said:

sorry to ask this but for all of us less informed what does CBR and CHR stand for?

 

Here is a paper with some morphometric data on Jurassic theropod teeth. It has a list of common abbreviations in relation to dinosaur teeth

AL: apical length (in mm); CA: crown angle, using the formula of the law of cosine [2]; CAA: crown apical angle; CBL: crown base length (in mm); CBR: crown base ratio (CBW/CBL); CBW: crown base width (in mm); CDA: crown distal angle; CH: crown height (in mm); CHR: crown height ratio (CH/CBL); DA: distal apical-crown serration count per 5 mm; DC: distal mid-crown serration count per 5 mm; DB: distal base-crown serration count per 5 mm; MA: mesial apical-crown serration count per 5 mm; MC: mesial mid-crown serration count per 5 mm; MB: mesial base-crown serration count per 5 mm; DSDI: denticle size difference index, MC divided by DC

[Troodon]

Boy it's not easy but my best guess is Megalosauroidea focused on density being much greater on mesial edge and only going part way down the carina and CBR.   Cannot do better than that.

[Anomotodon]

28 minutes ago, Troodon said:

Boy it's not easy but my best guess is Megalosauroidea focused on density being much greater on mesial edge and only going part way down the carina and CBR.   Cannot do better than that.

 

Thank you! Still more certain than Theropoda indet.

Also, another question... I have recently acquired this broken foot claw from Judith river for a fairly cheap price, it was sold as an Ornithomimid although I very doubt it. However, crocodile claws look different too, without these 3 holes on the underside, maybe another maniraptoran or is it unidentifiable in this preservation?

 

[Troodon]

It does have an overall appearance of an Ornithomimid foot claw.  It's a shame the tip is broken looks like it was there at some recent point.  Ornithomimid claws have a depression on the ventral side which is missing and those three holes are not typical.  So I agree with you.  What size is it?

 

Ornithomimid claw

[Anomotodon]

19 minutes ago, Troodon said:

It does have an overall appearance of an Ornithomimid foot claw.  It's a shame the tip is broken looks like it was there at some recent point.  Ornithomimid claws have a depression on the ventral side which is missing and those three holes are not typical.  So I agree with you.  What size is it?

 

Size is 22 mm, forgot to add it. Comparing to your topic, maybe Leptoceratops? Lateroventral extensions (can't find right claw terminology) are smaller than in any theropods, but I can't find anything with these 3 holes.

 

[Troodon]

The dorsal side on a Lepto is pretty flat so I don't think do.  I just don't get a dinosaurian vibe but don't know.

 

@hxmendoza any thoughts?

[hxmendoza]

On 3/5/2018 at 5:42 AM, Troodon said:

The dorsal side on a Lepto is pretty flat so I don't think do.  I just don't get a dinosaurian vibe but don't know.

 

@hxmendoza any thoughts?

 

I don’t think it’s dinosaur. Superficially looks Ornithomimid, but it’s dorsal profile doesn’t match up and those three prominent foramina are definitely unusual.

 

I’m wondering if it’s possibly turtle. They have such a wide variety of looks when it comes to their claws. For that matter, crocodilians do too...