Is this a 3 toed horse, or just a pathologic modern horse?

[fossilus]

I found this horse molar (right tooth in the photo).  It seems to have an isolated protocone as 3 toed horses do, but it is large (31mm left to right) and looks almost the same as most equuid teeth I have found.  It is about 95 mm long- and does have a curve which you don't see in the photo. 

Large 3 toed horse or is it pathologic?

@Shellseeker

[fossilus]

[Brandy Cole]

It sure looks like an isolated protocone to me, but size is important.  

 

@Harry Pristis has a very informative chart about how to take the right measurements for comparison.

 

 

And here's an informative thread about size

 

:

 

[Shellseeker]

So,

I already know what his response will be because I have had the exact discussion with Hulbert previously.

It is Equus,  but maybe one of the transitional Equus at the start of the Pleistocene.

However, the base question is what characteristics/crown height of this tooth produces an image of an isolated protocone on this tooth.

We still have the UF Florida Fossil identification Service.  You should send this Horse tooth ,  requesting an identification/explanation.  It would be helpful for other TFF members.

@fossillarry

 

 

 

 

[fossillarry]

In H. F. Osborn's great tome of 1918 on fossil horses there is a picture of a horse tooth that looks very much like the specimen in question. It was first identified as Hippotherium princeps in 1890. it was found on  Peace Creek, De Soto County,Florida. Later, after the generic name Neohipparion was erected, the tooth was assigned to that genus ( again because of the narrow  elongate protocone ). In 1918 the tooth was sectioned about  12  millimeters below the crown  and it was found to have a connection from the protocone to the protoconuai  as in Equus.  At that time the tooth was reassigned to Equus princeps but princeps is not considered a valid species. Because many of the species assigned to Equus are not valid (ill defined) or synonymous (the same) as other species, giving a species name to this tooth is not appropriate. Fossilus"s tooth while being slightly curved (not uncommon in Eguus) and having a detached protocone from the protoconul ( exceedingly rare in later equine horses) all other feathers on the tooth crown are similar to Equus. So I think this tooth is Equus sp. Having said all this  the tooth is still a unique and uncommon variant of Equus. Very interesting find.

[Shellseeker]

On 10/16/2022 at 10:30 PM, fossillarry said:

In H. F. Osborn's great tome of 1918 on fossil horses there is a picture of a horse tooth that looks very much like the specimen in question. It was first identified as Hippotherium princeps in 1890. it was found on  Peace Creek, De Soto County,Florida. Later, after the generic name Neohipparion was erected, the tooth was assigned to that genus ( again because of the narrow  elongate protocone ). In 1918 the tooth was sectioned about  12  millimeters below the crown  and it was found to have a connection from the protocone to the protoconuai  as in Equus.  At that time the tooth was reassigned to Equus princeps but princeps is not considered a valid species. Because many of the species assigned to Equus are not valid (ill defined) or synonymous (the same) as other species, giving a species name to this tooth is not appropriate. Fossilus"s tooth while being slightly curved (not uncommon in Eguus) and having a detached protocone from the protoconul ( exceedingly rare in later equine horses) all other feathers on the tooth crown are similar to Equus. So I think this tooth is Equus sp. Having said all this  the tooth is still a unique and uncommon variant of Equus. Very interesting find.

I know a little about Florida fossil horses. You post infrequently. For every post you create, I learn new things and I am stunned by the level and  depth of your knowledge.  Thanks for your support of this forum but mostly for the additional insights that I have which are based on your posts. Jack

[Harry Pristis]

On 10/16/2022 at 10:30 PM, fossillarry said:

Fossilus"s tooth while being slightly curved (not uncommon in Eguus) and having a detached protocone from the protoconul ( exceedingly rare in later equine horses) all other feathers on the tooth crown are similar to Equus. So I think this tooth is Equus sp

To fossillarry's excellent analysis, I can only add that the curve in Equus teeth, uppers and lowers, is not simply "not uncommon" -- it is the norm.