The U.S. Forest Service (USFS) has recently discovered “new” dinosaur trackways along the Purgatoire River, Picket Wire Canyonlands, south of La Junta on the Comanche National Grassland. About 65 volunteers of all ages assisted USFS paleontologists in uncovering more than 45 “new” dinosaur tracks and three “new” trackways. Volunteers included Boy Scout Troops 30 and 232 and Cub Scout Packs 5, 237 and 412 from Pueblo and La Junta, Colorado as well as others from Colorado, Kansas, Oklahoma and Arizona.
The “newly” discovered dinosaur tracks were once exposed by the action of the Purgatoire River, but became covered by modern river sediments in the past century. The re-exposed tracks are especially important because they contain parallel trackways of three sub-adult sauropod dinosaurs. The similar size, gait, and trend of these sauropod trackways strongly suggest the animals were traveling together in a group. The Purgatoire tracksite is one of the first places where gregarious behavior in dinosaurs was first postulated based upon the behavior recorded in the tracks, and the newly re-exposed tracks provides further support for this theory. The “new” trackways parallel ripple marks indicating that sauropod dinosaurs walked along the shore of a shallow freshwater lake. There is also high potential for continuation of the “new” sauropodtrackways because the limestone dips downward, indicating a prehistoric swale with more muddy conditions. Dinosaurs walking through muddier areas sunk deeper into to the mud thus increasing the likelihood that their tracks would be preserved.
The Purgatoire dinosaur tracksite is a world renowned paleontological site dating to the Jurassic Period, and records compelling evidence that plant eating sauropod dinosaurs (brontosaurs) lived in herds while meat-eating theropods like Allosaurus were solitary. Over 1300 prints in 100 separate trackways extend across a quarter mile expanse of bedrock where they were preserved for 150 million years.
VISITING THE TRACKWAY
The Picket Wire Canyonlands Guided Auto Tour is the easiest way to visit and learn about the new discovery. During the tour, knowledgeable guides also show visitors difficult to find dinosaur tracks and point out the interesting prehistoric, historic and natural features of the canyons.
All day tours (8:00 a.m. – 4:00 p.m.) are offered on Saturdays and some Sundays in June, September and October for a small fee. Due to rough roads, visitors will need their own four-wheel drive vehicle. To make reservations go to: www.recreation.gov or call 877-444-6777. For additional information call the Comanche National Grassland in La Junta, CO at 719-384-2181.