HE SCOURS THE DESERT FOR OLD bones, but University of Chicago paleontologist Paul Sereno claims to have found the fountain of youth there as well. “Go out in the middle of the Sahara for four months without showering,” advises the 39-year-old associate professor, who can still be mistaken for an undergrad on campus. “It does your skin wonders.” Sereno, who is married to educator and freelance writer Gabrielle Lyon, lives an Indiana Jones existence, traversing the ancient soil of South America, Asia and Africa clad in dusty blue jeans and a turquoise earring. Last year in Morocco his team discovered the fossils of a new dino species, the Deltadromeus agilis. “People are attracted to the adventuresome lifestyle,” says the 5’10” Sereno, who has made documentaries for PBS and written about his expeditions for National Geographic. “I think you could take someone who’s reasonably attractive and put them in a white lab coat, and they wouldn’t look as attractive as if you put them in field clothes in the middle of the desert.” Maybe so, but Sereno’s passion for his work is also part of the appeal, says wife Gabrielle: “His best asset is his brain.” And his mother, Rena, an elementary school art teacher, crows that Paul has always been “rather astonishing looking.” Still, Sereno prefers to credit the dinosaurs. “If you love what you’re doing,” he says, “you’re going to reflect that in your looks.”