 This fall, the only green dinosaur fossil ever discovered will be on display at the Natural History Museum of Los Angeles County. Daniel Martindale reports. The dinosaur is nicknamed Natalie with a silent G for the gnats that swarmed a crew during the excavation process in the Badlands of Utah in 2007. The long-necked, long-tailed herbivore lived an estimated 150 million years ago during the late Jurassic era, making it older than the T-Rex. Most dinosaur fossils are brown or black.