Parts of two ancient elephant relatives were found in the past week during excavation work on the future Wilshire/La Brea Station for the Purple Line Extension subway, Metro announced today. These are the first fossils from a mammal species found during work on this section of the subway project.
A three-foot section of tusk and mastodon tooth fragments from an adult were found just before Thanksgiving as part station excavation. Subsequently, a partial skull with tusks of a possibly much younger
mammoth or mastodon was discovered on Monday in the same location on the southwest corner of Wilshire Boulevard and La Brea Avenue, about 15 feet below street level.
Mammoths and mastodons are both distantly related to elephants. Columbian mammoths found in California were slightly larger than the American mastodon. Mammoths were more of a plains animal with tall “washboard-like” flat teeth that could stand up to chewing tough grasses with silica, while mastodons tended to roam brush and forests while eating mostly leaves, fruit, and flowers — so their teeth had low crowns. Both species went extinct in North America at least 10,000 years ago during a wave of large animal extinctions following the last Ice Age.
The remains of these type of large animals have been found at the nearby La Brea Tar Pits. Because fossils were expected to be unearthed during subway work, Metro has hired paleontologists from a firm named Cogstone to monitor excavation work and help identify and preserve fossils found during construction. When such finds are made, construction work is immediately stopped in the area until the fossils can be preserved and removed.
Both the tusk section and skull have been encased in plaster — similar to that used in making casts for humans — in order to be removed from the site intact and taken to a lab for further analysis. An analysis of the teeth and other features of the skull will tell whether the animal was a mammoth or mastodon. The skull will ultimately be handed over to the Natural History Museum of Los Angeles County.