With visions of the gigantic T-rex from "Jurassic Park" wreaking terror in their minds, the four visitors beheld the skimpy remains of the world's oldest known tyrannosaur with a twinge of disappointment.
"I thought there would be some more than this and it would be bigger," said Dr. Nara Vaeusorn, a radiology professor at a Bangkok hospital. "But Thailand can still be very proud of it."Staring back from the dry stream bed, oblivious to Hollywood blockbusters or national pride, lay the tail bones of an ancestor of tyrannosaurus rex experts estimate are 20 million years older than any previously known specimen.
Recent publication of the discovery in the scientific journal Nature revealed to the world - and most Thais - that this Southeast Asian country has proven a treasure trove of dinosaur fossils since excavations began just 15 years ago.
Buddhist monks find bones after seeing dinosaurs in meditations. Villagers plunder fossils in the belief they have magical powers. Even the semirevered royal family has a dinosaur named after it.
But few knew much about Thailand's dinosaurs until the tyrannosaur discovery was disclosed.
"Everybody knows tyrannosaurus from `Jurassic Park,' " said Varavudh Suteethorn, chief paleontologist in the country's dinosaur digs. "And since this is the oldest known ancestor, everybody is curious."
A geologist uncovered the tyrannosaur fossils in 1993 at the Phu Wiang National Park, an oasis of rocky hills and trees some 250 miles northeast of the capital, Bangkok.
The park lies in the Korat Plateau, where fossil-rich Mesozoic-era sedimentary rock has been thrust to the surface. Most Thai fossils have turned up there since a geologist seeking uranium found a dinosaur thigh bone in the late 1970s.
Like most fossil finds, the tyrannosaurus skeleton was only partial. The surviving portion - the tail and pelvic structure - probably lay more deeply buried than the rest in primordial mud that turned to stone.
But what remained was enough for Suteethorn and Eric Buffetaut, chief French paleontologist in the Franco-Thai team coordinating the fossil research projects, to identify a tyrannosaur from the telltale hip structure.
At 21 feet long and weighing 2 tons, the predator was about half the length and a third the weight of its monster descendant, tyrannosaurus rex, but looked very similar.
It lived 120 million to 130 million years ago, about 50 million years before the oldest traces of T-rex found in Asia and North America. The find bolsters theories that tyrannosaurs evolved in Asia and migrated to North America - like humans millennia later.
The beast has been dubbed Siamotyrannus Isanesis, after Siam, the old name of Thailand, and Isan, the northeast region where it was located.
News of the discovery has sent a flood of visitors - up to 1,000 a day on holidays - to the formerly sleepy national park for an arduous climb to see the remains.
The hip has been removed to France for study, but the tail bones remain, surrounded by chain link fence and protected from seasonal rains by a tin roof.
Visitors are allowed to gently touch the bones, believing doing so will bring long life.
Local and national officials, arguing over tourist revenue and scientific preservation, are bickering over which proposed natural history museum should house the bones.
Meanwhile, rangers keep watch around the clock to keep away thieves who have stolen bones from some of Thailand's 25 other sites to make magic charms.
"We try to educate people that this is our country's precious heritage," said Sathathorn Polandlam, a ranger who guides visitors. "But people think if they make a Buddha image from a bone, they can't be wounded by a knife or bullet."
Northeastern Thailand may be the country's poorest province, but it's rich in dinosaur remains.
Suteethorn believes that the tyrannosaurus find is outweighed by the graveyard of at least six plant-eating dinosaurs discovered at a Buddhist monastery about two hours drive east of Phu Wiang.
The venerable 71-year-old abbot, Prakru Vichitsahasakul, found the first bone himself.
"I first saw a dinosaur in 1992 when I was meditating," Vichitsahasakul, wrapped in a saffron robe, tells the curious kneeled at his feet in a temple where golden images of the Buddha mingle with plastic toy dinosaurs.
"At that time, I had no idea what kind of animal it was," Vichitsahasakul recalled. "It was huge, a lot bigger than an elephant, and had a long neck."
In 1994, Vichitsahasakul had the longest meditation of his life - three days and three nights - filled with dinosaurs.
The monk went to the site in his visions, where a road was under construction at the monastery. He started digging and found bone fragments.