The Ashfall Fossil Beds is a Late Miocene aged fossil site in northeastern Nebraska notable for its lagerstätten conditions that were caused by an eruption of the Yellowstone Hotspot 10-12 million years ago.
Geology[]
The Ashfall Fossils Beds are part of the Ash Hollow Formation, which is in turn part of the Ogallala Group.[1] The fossils of the animals within the volcanic ashbed were killed in the Bruneau-Jarbidge eruption of the Yellowstone Supervolcano in modern day Idaho, with ash being carried nearly 1000 miles (1600 kilometers) by the wind, filling what at the time had been a watering hole in a savannah-like environment. The ash caused the animals that inhaled it to die of lung failure, which affected animals with smaller body sizes earlier and those with larger body sizes later. The ash also helped to preserve the fossils of the animals in three dimensions, although some animals do show evidence of being scavenged by animals such as Epicyon.[2]
Fossil Taxa[]
Taxa found in the Ashbeds[]
- Teleoceras, a rhino and the most common animal at the site
- Neohipparion, a three-toed horse
- Cormohipparion, a three-toed horse
- Pseudohipparion, a three-toed horse
- Pliohippus, a one-toed horse
- Protohippus, a one-toed horse
- Aepycamelus, a camel
- Procamelus, a camel
- Protolabis, a camel
- Longirostromeryx, a musk deer
- Cynarctus, a canid
- Leptocyon, a canid
- fossil tracks, corprolites, and bite marks from Epicyon, a canid
- Balearica exigua, an extinct species of Crowned Crane
- Apatosagittarius, a hawk that resembles the modern secretary bird
- Anchigyps, a relative of Old World Vultures
- Hesperotestudo, a giant tortoise
- An extinct species of Chrysemys, a painted turtle
- Sternotherus odoratus, the living Eastern Musk Turtle
Taxa not found within the Ashbeds but present in the sandstone beneath it[]
- Aphelops, a rhino
- Ustatochoerus, an oreodont
- Cranioceras, a three-horned deer-like animal
- a pronghorn similar to Proantilocapra
- Prosthennops, a peccary
- Aelurodon, a canid
- Carpocyon, a canid
- Leptarctus, a mustelid
- Ischyrocyon, an amphicyonid
- Eubelodon, a proboscidean
- Eucastor, a beaver
- Ceratogaulus, a horned rodent
- Untermannerix, a moonrat
- Ameiseophis, a snake