Cheyenne - A man pleaded guilty on Thursday to a felony charge of conspiring to smuggle fossils from China into the United States. He also agreed to forfeit any claim to a Tyrannosaurus skull that likely will be heading back home to Mongolia.Federal officials and a lawyer representing the government of Mongolia say the prosecution marks a continuing push to crack down on fossil smuggling.Rick Rolater, aged 69, entered the plea on Thursday before US Magistrate Kelly Rankin in Cheyenne.Rolater has sold fossils through two By Nature Gallery stores in Colorado. He faces a $25 000 fine and two years' probation under a plea agreement when he goes before US District Judge Scott Skavdahl for sentencing on 18 March in Casper.Rolater agreed to forfeit a saber-toothed cat skull and three dinosaur fossils imported from China.He also agreed not to contest forfeiture of two fossils from Mongolia, including the skull of a Tyrannosaurus Bataar, a close relative of the Tyrannosaurus rex. He didn't admit the Mongolian fossils were imported illegally.LootedThe investigation into Rolater's operations began when federal officials received a tip that the Tyrannosaurus skull in his Jackson gallery came from Mongolia, according to a statement by Homeland Security.The skull disappeared from Rolater's gallery after news reports that the agency had seized a separate Bataar skull in New York, according to the statement.Federal authorities in May 2013 returned a 70-million-year-old Tyrannosaurus skeleton to the Mongolian government.The repatriated skeleton had been looted from Mongolia's Gobi Desert and illegally smuggled into the US by fossils dealer Eric Prokopi, authorities said. Prokopi, who bought and sold dinosaur skeletons out of his Florida home, illegally imported the bones into the US and assembled them into a skeleton, authorities said.According to the Homeland Security statement, after the Tyrannosaurus skull disappeared from Rolater's Jackson gallery, federal agents secured a search warrant and recovered the skull in June 2012 from a residence he owned.Federal prosecutor Stu Healy said in court that Rolater had received fossils from a man in China. Healy said they were exported from China and brought into the United States without regard for the customs laws of either country.Cheyenne lawyer Pat Crank, who represented Rolater at Thursday's plea hearing, said Rolater originally thought he was dealing with a legitimate fossil exporter.ZealUnder questioning from Rankin, Rolater acknowledged that as the relationship with the Chinese exporter developed, Rolater did try to violate federal laws.Speaking after Thursday's court hearing, Crank said his client was caught in the federal government's zeal for prosecuting such cases."It's unfortunate that there are literally thousands of these things out there, and for years, no one regulated the importation or the sale of any of these fossils," Crank said."Now all of a sudden the rules have changed, and real nice people like Rick Rolater get caught up in importing and selling what literally thousands of people do."Houston lawyer Robert Painter represents the Mongolian government in trying to reclaim fossils that have been smuggled out of that country. He said on Thursday that the Wyoming case got traction following the widely publicised return of the other Tyrannosaurus Bataar to Mongolia.Painter said the Mongolian government has put the repatriated Tyrannosaurus skeleton up for display in a temporary structure in the capital city of Ulaan Baatar. He said than 750 000 of the country's roughly 3 million people had seen it by the end of last year.Painter said Mongolia is working to convert a museum once dedicated to former Soviet leader Vladimir I Lenin to house the Tyrannosaurus skeleton and other dinosaur fossils.