About 12 million years ago, you really didn't want to mess with Texas.

From alligators to bizarre antelope to shovel-mouthed behemoths, Texas was a strange and savage place. At least, that's the picture painted by a huge trove of fossils originally dug up in the late 1930s.

Scientists at the University of Texas documented the fossils, along with how they were gathered, this month in the journal Palaeontologia Electronica. And those bones paint a vibrant picture of what the Lone Star State was like back in the Miocene Epoch. In all, researchers catalogued some 4,000 specimens, representing about 50 species. Among them were rhinos, camels and antelope with slingshot-shaped horns.

"It's the most representative collection of life from this time period of Earth history along the Texas coastal plain," study author Steven May of the University of Texas noted in a statement.

Jaw and shoulder blades from an extinct rhino species. Jaw and shoulder blades from an extinct rhino species. (Photo: The University of Texas at Austin Jackson School of Geoscience)

Perhaps even more surprisingly, many of the pieces of this lost world had been idling in storage for the last 80 years. The fossils were originally gathered between 1939 and 1941 by out-of-work Texans who were recruited to dig up fossils as part of a public works project.

At the time, with the Great Depression looming, the Works Progress Administration (WPA) was keen to get Americans working again. So in partnership with the University of Texas Bureau of Economic Geology, the federal agency funded the State-Wide Paleontologic-Mineralogic Survey.

The program turned unemployed Texans into fossil hunters, gathering bones and minerals from sites across the state. In a mere three years, these amateur paleontologists raked up thousands of fossils, most of them from dig sites in Bee and Live Oak counties.

Men carry a giant bone from a dig site in Texas. Glen Evans (left), who managed much of the Works Progress Administration's effort to collect Texas fossils, is pictured here carrying a fossil in a field jacket with a worker. (Photo: The University of Texas at Austin Jackson School of Geoscience)

After the program ended, most of those relics ended up at the Jackson School Museum of Earth History — with only sporadic studies on them getting published.

The work of May and his team represents the first time the collection has been studied in its entirety. And it has opened an unlikely but spectacular window to the region's unlikely past — as well as its strange inhabitants.

An elephant, for example, once roamed the region that boasted a shovel-like jaw. In addition, ancient fossils suggest American alligators and rhinos once prowled the region, as well as an extinct relative of modern dogs.

Fossilized skulls recovered from Texas dig sites. The skull of a shovel-jawed, elephant-like gomphothere (pictured at bottom) still wrapped in its field jacket. (Photo: The University of Texas at Austin Jackson School of Geoscience)

If it seems like Texas was a land of giants, researchers say there's a reason for that. Those amateur fossil hunters of the Great Depression got most excited about the big bones. Tusks, teeth and skulls from those animals stood out — and, like any excited first-time fossil hunter, they dug them out of the Earth first.

"They collected the big, obvious stuff," May explained. "But that doesn't fully represent the incredible diversity of the Miocene environment along the Texas Coastal Plain."

Rhinos and weird elephants once roamed Texas
Researchers are calling the wild lands of 12 million years ago the 'Texas Serengeti.'