Skulls, Skeletons, Canines & Claws

[tigerluver]

(05-19-2021, 01:00 PM)Panthera Wrote:

(05-19-2021, 10:22 AM)tigerluver Wrote: @Panthera,

An interesting carnassial and great thoughts, thanks for sharing. The age does make the classification less certain. 

Dentition are really hard to classify because they are so variable, especially in the lateral view. Take a look at collage from Jiangzuo and Liu (2020).:

*This image is copyright of its original author

Also a diagram from Marciszak et al. (2014) to calibrate ourselves with the anatomy:

*This image is copyright of its original author

What catches my eye on the M. microta P4 is the shape of the protocone. Despite the massive variation in carnassial shape, in pantherines the posterior contour of the protocone is diagonal from the base to the apex. However, in M. microta the posterior contour starts of diagonal then sharply switches to be nearly straight. As I see it in the photos, your P4 seems to have the pantherine contour. However, if you are able to take a photo with the cusps positioned closer to midline we could check to see if the contour of the protocone appears different. 

*This image is copyright of its original author

Thank you for the detail reply. It is a pity I do not know exact date. I know this is difficult identify species from a single carnassial. The posterior contour of protocone method is interesting, I learn a important thing. 
Response to Fig 4. of Jiangzuo and Liu (2020), In terms of size alone, this P4 fossil size only correspond with living tiger and lion, but maybe ancient species such as leopard or other species bigger than modern one... 
Are these photos okay?

*This image is copyright of its original author

*This image is copyright of its original author

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In addition, I found something interesting is the Yunnan P4 and Manchuria P4 have common feature on protocone area as marked(It is cavity, exact location between parastyle, protocone and paracone), I guess it's tooth decay or tooth wear with the frequency of use.  

*This image is copyright of its original author

*This image is copyright of its original author

Those are excellent photos and good eye! By this view, the posterior edge of the protocone is even more diagonal, which fits with pantherines.

I took some more observation from Jiangzuo and Liu (2020) and found some more aspects in common with the tiger.:

1. Straight buccal border (in e in the figure previously posted).
2. Well-developed ectoparastyle (in d in the figure prevously posted).
3. A lack of buccal concavity.
4. Large protocone. 

Interestingly, if we look at P-Q (leopard) we see that straighter protocone posterior contour that tigers lack. Given the very diagonal protocone in your P4, it seems to make the leopard a less likely candidate. 

Here's a labeled diagram:

*This image is copyright of its original author

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