Horse Proximal Phalanx sizes

[Shellseeker]

I made it out hunting Thursday and Friday,  found some treasures I am still sorting. Also , met up with a friend who has been finding some early horse fossils and wished to give to the opportunity to acquire them. He had a very nice , very small upper molar. and a couple of Proximal Phalanx... 

 

The Phalanx were of a size to make me wonder if they were pre_Equus or Equus.  One is just under 3 inches and the other under 2.5 inches.

 

do we move from Equus to pre_Equus and then down to what I believe is the smallest of the Florida small horses, Nannippus morgani ?  For Reference , in his Gallary, @Harry Pristis has a 52 mm ( 2.07 inch) Phalanx of Neohipparion eurystyle. The UF MNH Database has a 48 mm (1.9 inch) Nannippus peninsulatus Phalanx and a 40 mm (1.6 inch) Nannippus aztecus.

 

As I searched Harry's Gallary for answers,  I found this picture,  NOTE the words "Sizes vary Substantially".  As these things happen @Brandy Cole had found a rather large Horse Proximal Phalanx (3.75 inches) and asked this question:

Quote

Thank you for the resource! 

Here, you've noted that size varies substantially.  I recently found what I believed to be a Pleistocene proximal equus phalanx based on your examples, but mine measures about 3.75 inches in length.  Is that outside the reasonable size range for equus? 

 

I do not know what the upper end on size for Equus Proximal Phalanx.  Maybe another TFF member can suggest one from their fossil collection. I sort of wonder about Clydesdales.

From what I can derive from the sizes on Nannippus peninsulatus and aztecus, the lower end on Horse Proximal Phalanx (at least in Florida) might be 1.4 inches or 36 mm. That does not include the pre_Nannippus horses (like Parahippus), which are not in my south central Florida hunting locations.

 

So,  we have equus at 69 mm, eurystyle at 52 mm and I have just acquired one at 60 mm. If any member has identified a 60 mm Proximal Phalanx, please post.... Thanks  Jack

 

 

Edited February 5, 2022 by Shellseeker

[Harry Pristis]

Hmm . . . That size measurement is misleading because of its position in my image.  I never measure mid-line, always maximum length.  So that 69 mm is the maximum length.  The mid-line length of the pictured proximal phalanx would be smaller.

[Shellseeker]

1 hour ago, Harry Pristis said:

Hmm . . . That size measurement is misleading because of its position in my image.  I never measure mid-line, always maximum length.  So that 69 mm is the maximum length.  The mid-line length of the pictured proximal phalanx would be smaller.

Thanks, Harry.

I have just gone in and replaced the photos of my acquisitions, adjusting the lengths,  Each added about 5 millemeters, putting the 2nd over 3 inches and clearly  Equus. The smaller is now 65.5 millemeters.  They may both be Equus.

Looking for Identified Proximal Phalanx between 52 and 69 millemeters.... that's about 2/3rds of an inch

[Brandy Cole]

So the phalanx that I found that @Shellseeker referenced is this one, which was around 3.75 inches.  So it was well over 90mm based on my past measurements.  I would have to dig it out to get it accurate to the precise millimeter.  I thought it looked like equus, but the size alone has made me wonder, especially since it looks like equus phalanx size range is smaller. 

 

It sounds and feels mineralized, and I found it in a place where mineralized bone and bone fragments are common but modern bones are rare.

 

This post reminded me that I have never really been able to confirm if it's equus or if I should consider other options.

 

 

[Harry Pristis]

Like human beings, equus horses come in a range of sizes.  Morphology, rather than size, is the most reliable diagnostic feature in this case, I think.

[Shellseeker]

6 hours ago, Brandy Cole said:

This post reminded me that I have never really been able to confirm if it's equus or if I should consider other options.

As Harry indicates, Morphology (i.e the structure and shape ) of your fossil will be very similar to the same fossil in in other members of the same species and not so similar to the same fossil in members of a different species.

So, I have added a fossil that except for size (mine is only slightly over 3 inches) seems very similar to yours.  My fossil is an Equus Proximal Phalanx. Mine might be a female of juvenile,  yours from a male...