Park rangers are offering a reward for information about whoever damaged a fossil at Dinosaur National Monument.

On Tuesday, a ranger leading a guided tour discovered damage to a sauropod's fossilized humerus bone along the Fossil Discovery Trail. Part of the lower half of the humerus is missing, damage that wasn't evident the day before, according to a National Park Service news release.

The 1.2-mile trail runs between the Quarry Visitor Center and the Quarry Exhibit Hall, where the famous wall of dinosaur bones is located.

"The trail is unique as it is one of the few places where visitors can hike to see and touch unexcavated dinosaur fossils and fragments in situ; or still in place," the release reads. "… While the fossils have limited scientific value, they have a great value for the educational experience they provide to visitors and students who hike the trail."

Rangers want anyone with information to call them at 435-781-7715. A $750 reward is available for information that leads to a conviction.

The fossils in Dinosaur National Monument are protected, and may not be collected, according to the release. The same goes for any rocks, plants, animals and cultural artifacts in the park as well.

mmcfall@sltrib.com

Twitter: @mikeypanda