6 small upper horse teeth

[Shellseeker]

My last time out hunting was 2 weeks ago, just before the deluge.  Found some nice items including 2 small upper horse teeth, and then stopped at a hunting friend's home, where he sold me a number of fossils,  including 4 additional small horse upper molars. 

1st tooth I believe to be Merychippus from the Miocene of Florida. I found/donated one of these to Richard Hulbert, Florida Museum of Natural History 18 months ago. It looks like some HSBs --- Hunter_Schreger Bands are more easily discernible than on Equus teeth.

Tooth #2.... One of my finds... a Nannippus I think... there were 4-5 species in Florida

Tooth #3

Another Nannippus.... little bit larger... Look at that isolated circle on the left ... I wonder if that is diagnostic.

 

Tooth # 4 is once again larger... might be Nannippus, but I am less sure....

 

Tooth #5  is not Nannippus,, which leaves lots of other Genus

 

and lastly an interesting ,  different and slightly damaged tooth...  Definitely need a thread to follow on this one...

 

I have sent the Photos to Richard Hulbert, but with his semi_retirement, I would like to start depending on TFF expertise....   Usual suspects,   @Harry Pristis, @fossillarry @siteseer @darrow

 

Thanks for any and all insights and threads to follow...  as Always I am after Genus, Species,  Jaw position. All this starts with Genus.

[Meganeura]

Unfortunately I don't think Hulbert will be of much help - I sent him off some fossils (pictures) 2 weeks ago, and then pictures of the canine/whale or whatever tooth from last week, and haven't heard back yet. I know he's busy-busy getting everything set up for Rachel to take over as collections manager.

Can't help with the horse teeth - but they're very pretty teeth!

Edited September 18, 2022 by Meganeura

[Fin Lover]

Although I'm sure there are differences that I'm not experienced enough to notice, it looks pretty similar to one I found the last time I hunted. Mine is about 23mm x 23mm, though, and full of matrix.

[Shellseeker]

@Fin LoverThanks for the comments. I have been fossil hunting in lower Florida for about 15 years, and at the start  I knew nothing about the history of horses.

At a very high level , Horses started in South America, crossed to North America over the Panama land bridge, into the old world via a land bridge across the the Bering Strait,  went extinct in the Americas some 15000-20000 years ago,  and then were reintroduced by the Spaniards in the 1500s. Those horses living in Florida (and maybe South Carolina) 15000 years ago were about the size of today's Horse. but their ancestors , living 5-10 million years ago in Florida were small , really small sometimes the size of Labrador retrievers today.... and they had small teeth..

The horses that lived 5-10 mya were the ancestors of Equus that lived the last million years, and there was a gradual transition of what a horse tooth looked like , and especially the size.

Look at my #2 above,  it has a length of 11.8 mm, about half the size of the horse that had your tooth, and likely lived about 10 mya. There were numerous genus/species of horse back 10 mya. One of the identifiers many or most of those genus/species had an "Isolated protocone",  that oval circle at the bottom of the tooth that does not touch other raised enamel.  So now you do know a couple of differentiators  1_size=length and 2_isolated protocone.

 

Some scientists might identify your tooth as early Equus or Equus Complicatus

They looked like this:

 

[Fin Lover]

Thanks for the information, Jack!  So, does mine have a non-isolated protocone, or what is the term for that?  Also, is size always indicative of the species, or won't younger horses have smaller teeth than adults?

[Meganeura]

50 minutes ago, Fin Lover said:

Thanks for the information, Jack!  So, does mine have a non-isolated protocone, or what is the term for that?  Also, is size always indicative of the species, or won't younger horses have smaller teeth than adults?

Size is almost always indicative of species - I can't remember the specifics, but I know the teeth grow longer and develop as the horse gets older. For example - the spit tooth I found is roughly the same crown size as the adult molar I found:

 

But obviously the spit tooth is from a juvenile. 

(Also sorry Jack to hijack your ID thread!)

 

Edited September 19, 2022 by Meganeura

[Fin Lover]

42 minutes ago, Meganeura said:

(Also sorry Jack to hijack your ID thread!)

 

Yes, Jack, I'm sorry to take the focus away from your ID.  You were kind enough to take the time to explain how my tooth was different from yours and I should have created a different post for my additional questions.

[Shellseeker]

49 minutes ago, Fin Lover said:

Yes, Jack, I'm sorry to take the focus away from your ID.  You were kind enough to take the time to explain how my tooth was different from yours and I should have created a different post for my additional questions.

Here is what I am thinking... There are not a lot of members who have seen enough of these small pre_Equus horses  to be able to contribute.  It is not that they do not want to, just they have limited knowledge.  I am "fishing" for those with knowledge and the hope that I keep the community interested in them. In the meantime,  discussions like ours keeps pushing this thread back to the top.. and attract attention..

SO, it is OK to continue... Here is a clear photo of Equus, you sort of have a protocone,  it is just not "isolated" . It is connected by a piece of raised enamel coming from the top...  see it ?  Equus gets two sets of teeth,, a Deciduous set of baby teeth and then adult teeth that emerge after the 1st year. The deciduous set is slightly smaller...

 

I am confused about South Carolina....

https://en.wikipedia.org/wiki/Nannippus

Quote

Nannippus is an extinct genus of three-toed horse endemic to North America during the Miocene through Pleistocene "[http://www.fossilworks.org/cgi-bin/bridge.pl?a=collectionSearch&collection_no=19761", about 13.3—1.8 million years ago (Mya), living around 11.5 million years.^[1][2][3] This ancient species of three-toed horse grew up to 3.5 feet (1.09 meters) and weighed between 165 pounds to 199 pounds, which was around the same size as a domestic sheep.^[4][5]

Nannippus lived as far south as central Mexico (N. peninsulatus) to as far north as Canada (N. lenticularis), to California in the west, and North Carolina (N. lenticularis) and Florida (N. peninsulatus) in the east.

Nannippus has been found in Nebraska, Oklahoma, Kansas, Texas, Alabama, North Carolina, Florida during the Miocene and Pliocene... I can find no references for pre_Equus horses in South Carolina (or Georgia, Mississippi, Louisiana, Missouri, Arkansas) during the Miocene. What was going on with the landmass during the Miocene (25-5 MYA)? Sounds like there may have been a huge inland sea.

[Fin Lover]

Thanks, Jack.  Yes, I see how the protocone on my tooth is not isolated.  Here are a few things I've come across in the past about where the sea was in South Carolina.

[Shellseeker]

51 minutes ago, Fin Lover said:

Thanks, Jack.  Yes, I see how the protocone on my tooth is not isolated.  Here are a few things I've come across in the past about where the sea was in South Carolina.

There's a puzzle here... and I just do not have the time to work on it.... now

 

However,  I did get a response from Richard..... Fortunately for me,  he knows these small horse teeth by glancing at them...

 

Quote

The tooth (#1) labelled Merychippus could either be an adult upper tooth from a Merychippus OR a juvenile tooth from a high-crowned species, perhaps Nannippus. Can’t be sure as its unworn.

the three individual teeth are an upper third molar (#3) of either Nannippus or Pseudhipparion; an upper cheektooth of Cormohipparion emsliei (# 5...the one with complex folds on the fossettes); and last one is likely an upper premolar of Nannippus #4.

The one with three images (#6) is a Neohipparion eurystyle upper molar (M1 or M2).

Cheers, Richard

 

[Meganeura]

10 hours ago, Shellseeker said:

There's a puzzle here... and I just do not have the time to work on it.... now

 

However,  I did get a response from Richard..... Fortunately for me,  he knows these small horse teeth by glancing at them...

 

 

Richard responded to you, but not to me? How rude.  At least you got some responses though! The only teeth I've been able to find have been Equus and Nannippus so far. 

[siteseer]

6 hours ago, Meganeura said:

Richard responded to you, but not to me? How rude.  At least you got some responses though! The only teeth I've been able to find have been Equus and Nannippus so far. 

 

Richard gets tons of emails.  He's probably just swamped.

[Meganeura]

Just now, siteseer said:

 

Richard gets tons of emails.  He's probably just swamped.

I was kidding - I know he's super busy cause he's retiring! I don't blame the man anyway, he deserves a break after all he's done! And he replied anyway, so I can't really complain.