WHO: Zip, a Chihuahua-terrier mix, and the intrepid members of an Austin trail-running club and a pet rescue nonprofit.WHAT: A joyful reunion after the two-year-old pup was lost in Austin’s Barton Creek Greenbelt for 69 days. WHY IT’S SO GREAT: Zip knew the routine. On June 22, as on most Saturdays, his owner, University of Texas chemistry professor Mike Rose, woke his dog up at 4 a.m. so the two could hit the trails for one of their long runs. The two-year-old mutt had become something of a mascot in the Trail Roots running club. No matter the route, no matter the length—often fifteen miles or more—Zip was always there, off-leash at Rose’s feet. “I won the dog lottery,” says Rose, who adopted Zip from a…