They probably got most of the information from the age and diagnostic artifacts of the site. The age of a skull by itself is very difficult to estimate without radiocarbon dating unless the morphology is distinctly different (such as Kennewick Man).
Those earlier folks were here duing the time of the Whooly Mamouths, Saber Tooth Tigers, and Dire Wolves. Must have been right sporting getting enough to eat, and not being eaten in turn.
Actually, recent studies have suggested a more mixed, to even vegetal diet than had been thought. The megafauna was probably only an occasional treat.
And incidentally, this is the first time I have heard of a Native American skull referred to as a "prehistoric artifact" -- and I have been doing this for a lot of years, including a couple of decades examining bone finds for the local coroners.
I think these paleao-Amerindian skeletons should be studied scientifically.
Unless the remains are historic, i.e. within the last few hundred years, its absolute balderdash and nonesense for any tribe to claim them as their “ancestors”. Most Amerindian tribes moved around quite a bit. Take the Shawnees for example - they moved from the mid-west to the gulf coast area and back to the midwest again. The Souix originated in Minnesota and moved out into the great plains when they acquired horses. And all of this movement is within historical times.
Iroqouian lingusitic groups - found in eastern North America, speak a language most closely related to Caddoan tribes who lived in Texas. Obviously SOMEBODY moved there.
So this constant political pandering over these historical artifacts is political correctness gone insane.
This all started because in recent historical times there was a ghoulish practise among whites to exhume the remains of recenly interred Indians and put them on exhibit for the curious and idle masses, particularly those individuals who had been outstanding warriors.
The situation was allowed to escalate under the Clinton regime as certain Native Americans persist in believing their ancestors were ALWAYS here and rsent any efforts to show connections with old world ancestors from Asia or anywhere else.