Fossil bat skeleton - ROM2006_7684_1


Fossil bat skeleton

Place Collected
North America, USA, Wyoming, Lincoln County, Kemmerer
    • Attributes
    • Objects
    • Taxonomy
    • KingdomAnimalia
    • PhylumChordata
    • ClassMammalia
    • OrderChiroptera
    • FamilyOnychonycteridae
    • GenusOnychonycteris
    • SpecificEpithetfinneyi
Type Status:
Object number: ROMVP55055
Credit Line: Gift of the Louise Hawley Stone Charitable Trust
On view
Gallery Location:Reed Family Gallery of the Age of Mammals, Green River, Fossil Bats
DescriptionThis image represents Onychonycteris finneyi, the most primitive bat species known to date. Two specimens of this rare species have been unearthed in Southwestern Wyoming. The original of the first specimen found is still in private hands, and this photo is of a cast of it. The second specimen was found in 2003 and aquired by the ROM in 2004. Both specimens demonstrate that this species had the ability to fly before it could echolocate. Despite the fact that bats are so widespread and include a fossil record that extends over more than 50 million years, the evolutionary timing and development of both echolocation (sonar) and flapping flight has been widely debated. These specimens of Onychonycteris have provided researchers with the missing link between bats and their non-flying ancestors. Unlike any other bats previously discovered, Onychonycteris's physical characteristics revealed several surprising features. For example, it has claws on all five of its fingers, whereas modern bats have, at most, claws on only two digits of each hand. The limb proportions of Onychonycteris are also different from all other bats—the hind legs are longer and the forearm shorter—and more similar to those of climbing mammals that hang under branches, such as sloths and gibbons. The fossil's limb form and the appearance of claws on all the fingers suggest that Onychonycteris may have been a skilled climber. However, long fingers, a keeled breastbone and other features indicate that Onychonycteris could fly under its own power like modern bats. It had short, broad wings, which suggest that it probably could not fly as far or as fast as most bats that evolved later. Instead of flapping its wings continuously while flying it may have alternated flapping and gliding while in the air. Onychonycteris's teeth indicate that its diet consisted primarily of insects, just like that of most living bats. However, unlike living bats that echolocate, Onychonycteris lacks the ear and throat features present in all living echolocating bats, and even present in other fossil bats such as Icaronycteris.
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