UF9076–A Complete Skull and Jaws of a Giant Lion (Panthera atrox) Found in the Ichetucknee River, Florida

A little over 50 years ago, a lucky fossil hunter found the complete skull and jaws of a giant lion in the Ichetucknee River.  This remarkable specimen was missing just a few teeth.  One can imagine how exciting the moment of discovery was for the person who found it.  This particular skull is from a large male lion, and it is larger than almost every lion skull ever excavated from the La Brea Tar Pits in California.  The specimen belongs to the University of Florida Museum of Natural History, and the catalogue number is UF9076.

Location of Ichetucknee Spring State Park.  The Ichetucknee River flows through this state park into the Santa Fe River where giant lion specimens have also been found.

This is a skull of Panthera atrox found in Florida.  The genus name has been changed since the article in the above photo was published. Fossils of this species are rare in southeastern North America.

The type (or first) specimen of Panthera atrox was found in Mississippi during the 19th century.  For decades scientists debated whether this extinct Pleistocene species was a lion or tiger, but after skulls of big cats were readily available for comparison, paleontologists concluded Panthera atrox was a species of lion.  Until recently it was considered a subspecies of the extant lion still found in Africa and the Gir Forest of India.  But genetic studies suggest there were 3 distinct species of lions during the Pleistocene–the African lion (Panthera leo), the Eurasian “cave” lion (P. spelaea), and the American lion (P. atrox).  P. spelaea also ranged into Beringia north of the Ice Sheet that covered Canada while P. atrox occurred all across North America south of the Ice Sheet.  I don’t like referring to P. spelaea as a cave lion because most individuals never entered a cave in their lives.  They are called cave lions because that is where their remains were most commonly preserved.  These lions should not be confused with the cougar (Puma concolor), also referred to as the mountain “lion.”  Puma concolor is much smaller and not a closely related species.

Panthera atrox was on average 25% larger than extant African lions, and it had a larger brain.  Large males weighed up to 600 pounds.  Some scientists believe it was a solitary predator, unlike its living cousin.  They cite the lack of manes on paintings of lions in European caves.  The manes are evidence of male competition for mates within a social system.  However, some of the cave illustrations depict groups of lions.  There is no way of knowing for sure, but I lean toward the likelihood that Panthera atrox did live in prides because its closest living relative does.

Since the discovery of UF9076, specimens of Panthera atrox have been discovered at 20 other sites in Florida including the Santa Fe River, Vero Beach, the Gulf of Mexico (parts of which were above sea level during Ice Ages), Monkey Jungle Hammock, Cutler Hammock, St. Petersburg, Peace River, Lecanto, Waccasassa River, and Steinhatchee.  These are scattered throughout the state.  The jaw fragment with 2 attached teeth of a Panthera atrox was also found at Edisto Beach, South Carolina. (From measurements of the teeth, trained paleontologists determined it was from a small female lion.  The size slightly exceeds that of the largest jaguar distinguishing it from that species.  I’m not 100 % confident in this diagnosis, but I’ll defer to the experts.)  The presence of Panthera atrox at all of these sites indicates it occurred throughout southeastern North America during the late Pleistocene.

Panthera atrox co-occurred with jaguars (Panthera onca augusta) in North America but are less common in the fossil record of the east.  Jaguars prefer forested wet environments; extant lions inhabit more open plains, so one may assume P. atrox also preferred  open habitats.  Jaguars are probably more common in the fossil record because forested environments prevailed over open habitats in the southeast.  Nevertheless, the presence of P. atrox does suggest some extensive prairie and savannah habitat existed in the south.  They preyed on grazing bison and horses here.  Lions wandering through forests between pockets of savannah likely encountered jaguars and vice-versa.  Both species overlapped and competed with saber-tooths (Smilodon fatalis), scimitar-tooths (Dinobastis serum) cougars, dire wolves (Canis dirus), possibly doles (Cuon alpinus), and various kinds of bears.  What a curious ecological competition.

One final note: If P. atrox did prefer drier more open habitat, they would’ve been less likely to become preserved.  They died in the open, their bodies destroyed by the ravages of an unprotected environment.  By contrast jaguars like water and their remains would’ve been more likely preserved in watery springs and sinkholes.  Perhaps P. atrox was more common in the south than the fossil record indicates.

See also: https://markgelbart.wordpress.com/2012/05/02/three-pleistocene-lions-were-they-distinct-species-or-the-same-animal/

 

 

 

 

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Tags: Panthera atrox, the American lion, UF9076