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Giant Fossil Bird Found in Murrieta

"This partial humerus (upper wing bone) from Murrieta, California is the holotype specimen of the extinct bird genus Aiolornis.  In life, Aiolornis would have had a wingspan of 16 to 18 feet, making it the largest flying bird known from North America.  This fossil (catalogue number A2239-2829) was discovered by paleontologists from the San Bernardino County Museum in 1993. 
Scale bar = 1 cm."

A partial humerus (wing bone) of an extinct Incredible Teratorn, the largest bird of flight ever identified from North America, has been discovered by San Bernardino County Museum paleontologists from two million-year-old deposits near Murrieta, Riverside County, California. The find has resulted in a new name for the extinct avian giant: Aiolornis incredibilis, "the incredible bird god of the winds."

The discovery was made by Quintin Lake, senior field paleontologist for the San Bernardino County Museum. The fossil was described by Kathleen B. Springer, Senior Curator of Geological Sciences, and Eric Scott, Curator of Paleontology, also of the San Bernardino County Museum, working closely with fossil bird expert Kenneth E. Campbell of the Natural History Museum of Los Angeles County. The new find was announced in a Smithsonian Institution publication, "Avian Paleontology at the Close of the 20th Century."

Teratorns were the largest flying birds known. Teratorns living in South America during the Miocene Epoch, about 5 to 8 million years ago, reached a wingspan of 6 to 8 meters (up to 24 feet). The fossil from Murrieta suggests a wingspan of up to 5.5 meters (18 feet). A few scattered and fragmentary fossils of the Incredible Teratorn have also been discovered in Nevada and in the Anza-Borrego Desert in San Diego County. The Murrieta specimen is the most anatomically distinctive of these fossils, and analysis of this bone prompted a new name for the extinct predator.

"Our colleague, Dr. Campbell, determined that, although teratorns could fly, they were probably active predators who stalked their prey on the ground," explained Scott. "Think of Aiolornis as a scaled-down T. rex with feathers."

Springer observed, "Quintin’s find is the icing on the cake for us. For years the Museum has searched extensively in the rocks in and around the Murrieta area looking for fossil treasures. The giant teratorn is just one of thousands of fossils curated and housed at the SBCM from this region. It proves again that if you look in the right places, rocks can reveal abundant and exciting new information about past life."

Scott added, "Fossils of large animals from Murrieta are usually from extinct mammals — mammoths, mastodons, ground sloths, large horses and other animals of that size. Birds are very rare because their bones are thin and fragile and don’t often preserve well. Quintin’s fossil is most unusual in that context. We’re glad he has such good eyes!"

The specimen has been cataloged into the collections of the San Bernardino County Museum where it will be preserved for future study. A variety of fossils from southern California, including fossils from Murrieta, are presently on exhibit at the Museum.


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