14C1:
Georgia's First Pronghorn Ancestor,
Antilocaprid,
& The Oldest One in the Southeast!
By Thomas Thurman
19/June/2022
Rewritten after reclassification of fossil
24/July/2026
I was wrong.
The fossilized snout I identified as an oreodont isn’t an oreodont. Scientists at the Florida Museum of Natural History (FLMNH) identified its source as a member of the Antilocapridae family. It could not be identified further than that. The antilocaprids are a group restricted to North America who’s only surviving member is the pronghorn (Antilocapra americana). The closest modern relatives to pronghorns are giraffes. More on this in a bit.
The fossilized snout I identified as an oreodont isn’t an oreodont. Scientists at the Florida Museum of Natural History (FLMNH) identified its source as a member of the Antilocapridae family. It could not be identified further than that. The antilocaprids are a group restricted to North America who’s only surviving member is the pronghorn (Antilocapra americana). The closest modern relatives to pronghorns are giraffes. More on this in a bit.
The fossil is still kind of a big deal. It came from the Late Eocene’s Tivola Limestone which is between 34 and 35 million years old. “Early members” of the Antilocapridae family reportedly emerged during the Early Miocene (Wikipedia), say 20 million years ago.
Yep. I was wrong. In my defense, before the fossil was properly identified, two separate universities with natural history museums identified the fossil as an oreodont. In their defense the fossil was a partial snout, badly weathered, and all the teeth were missing. As seen above, it has been described as a “grim” specimen.
The fossil was found by amateur Jesse White more than a decade ago while shooting in one of the many abandoned Tivola Limestone quarries of Houston County. Good eye, Jesse.
The challenges with this fossil were finding a home for it, and getting it added to Georgia’s fossil record, there’s a process.
The Antilocapridae Family
The antilocaprids are hoofed ruminants, like cattle. They had multiple stomachs to help them digest tough plants; they chewed a cud. As mentioned, their closest living relative are giraffes. Like giraffes and cattle their horns had a bone core sheathed in keratin, modern pronghorns shed their horns outside of breeding season and then regrow them. The name pronghorn come from the fact that the horns are flattened, as if they’re two horns grown together, and there is a smaller forward point on each side with a larger upward point. Males have well developed horns, in females the horns are smaller or even absent.
The antilocaprids are hoofed ruminants, like cattle. They had multiple stomachs to help them digest tough plants; they chewed a cud. As mentioned, their closest living relative are giraffes. Like giraffes and cattle their horns had a bone core sheathed in keratin, modern pronghorns shed their horns outside of breeding season and then regrow them. The name pronghorn come from the fact that the horns are flattened, as if they’re two horns grown together, and there is a smaller forward point on each side with a larger upward point. Males have well developed horns, in females the horns are smaller or even absent.
The family is far more diverse when you look back on their natural history, there were species with full blown antlers, like those of a deer, but they were bony extensions from the skull sheathed in horn. There were species with flattened horns. There were species with distinct forward facing and rearward facing horns.
Modern pronghorns are famously fast runners reaching 40 mph (65 kph) over distances with sprints up to 52 mph (85 kph).
Modern pronghorns are famously fast runners reaching 40 mph (65 kph) over distances with sprints up to 52 mph (85 kph).
It’s historically believed that the antilocaprids emerged in western North America, their fossils are certainly more abundant there with multiple reports from most western states as well as Canada and Mexico. All of these reports are from Miocene and younger sediments. That suggests that either antilocaprids emerged earlier than previously thought, or the specimen is incorrectly identified.
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A Home in Florida
No home could be found for the antilocaprid fossil in Georgia. It was Roger Portell at the Florida Museum of Natural History who accepted the fossil despite some issues over collection permission. Portell had a relationship with the landowners. Seeing that a decade had passed they agreed that as long as the specimen was donated to the museum they would raise no objections to its collection. Now the fossil awaits publication, a process which will closely review the specimen, confirm it’s identification and attempt to answer the questions it raises. Once published, it can be added to the Paleobiology Database and become part of Georgia’s fossil record. |
References
- Huddlestun, Paul F.; Hetrick, John H,;Upper Eocene Stratigraphy of Central & Eastern Georgia, Bulletin 95, Page 24, Georgia Geologic Survey, 1986