Posts Tagged ‘Borophagine dogs’

First Bone-eating Dog (Borophagus sp.) Tooth Found in South Carolina

May 17, 2017

The Borophagine dogs were an incredibly successful lineage of carnivores that lived from ~34 million years BP to ~2 million years BP and perhaps beyond.  They ranged throughout North America from coast to coast and from Canada to Honduras.  16 species of Borophagine dogs are known from 12 different fossil sites in Florida alone, and in the rest of the southeast specimens have also been found in North Carolina and Maryland.  Recently, an amateur fossil collector found 1 pre-molar of a Borophagus in a spoil pile at the Martin-Marietta Orangeburg Quarry located in Orangeburg County, South Carolina.  This animal was probably common in South Carolina for millions of years, but this is the only known evidence it ever existed in the state.  Paleontologists examined the tooth and determined it compared favorably to a pre-molar of Borophagus hilli, a species that reached a weight of 130 pounds.  The age of this fossil is estimated to be between 3.9 million years BP-3.1 million years BP based on associated microfossils.  B. hilli co-occurred with another species of Borophagine dog–B. diversidensThey must have occupied different ecological niches, maybe like modern day wolves and coyotes.

Jaw bone of Borophagus hilli–the Pliocene bone-eating dog.

Image result for borophagus hilli

Artist’s depiction of the extinct bone-eating dog.  They had bulging foreheads.  Their teeth and jaws were similar to those of the extant spotted hyena–an example of convergent evolution.

Early species of Borophagine dogs were omnivorous.  Epicyon haydenii was the largest known species of canid in history, reaching weights of over 500 pounds.  This species lived between 12 million years BP-6 million years BP, and it probably occupied a bear-like ecological niche.  Borophagine dogs later evolved into more carnivorous forms, resembling modern day spotted hyenas (Crocuta crocuta) in build and dentition, hence the reason they’re often called bone-eating dogs.

Image result for Epicyon haydeni

Epicyon haydenii was the largest known canid in history, growing as large as a grizzly bear.  They were more omnivorous than their later descendants.  They lived during the Miocene.

Borophagus sp.

Scan of the lower 4th pre-molar of a Borophagus.  This is the only fossil evidence found in South Carolina of a species that was formerly common in the region for millions of years.

Despite their long reign as an important carnivore in the American ecosystem, Borophagine dogs became extinct during the late Pliocene or early Pleistocene.  The last species of Borophagine dogs co-existed with dogs belonging to the Canidae family for millions of years.  The Canidae were newcomers from Eurasia that crossed the Bering land bridge to reach North America.  Species from the Canidae family were better able to adapt to changes in the environment during the early Pleistocene and likely outcompeted Borophagine dogs, contributing to their extinction and completely replacing them ecologically.

Reference:

Tseng, Z. Jack; and Jonathan Geisler

“The First Fossil Record of Borophagine Dogs (Mammalia: Carnivora) from South Carolina USA”

Journal of Vertebrate Paleontology 36 (2) March 2016