Mesembriornis
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| Mesembriornis Fossil range: Late Miocene - Late Pliocene |
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Mesembriornis incertus |
Mesembriornis is a genus of intermediate-sized phorusrhacids (better known as "terror bird") that grew up to 1.5 meters in height. They represent a well-distinct lineage of terror birds, differing from the massive large groups and the smaller Psilopterinae. In general proportions, they most resembled the Patagornithinae which flourished somewhat earlier, mainly to the south of the range of Mesembriornis.[1]
Two species are nowadays accepted, Mesembriornis incertus and Mesembriornis milneedwardsi. Mesembriornis lived on the pampa of E and NW Argentina from the Late Miocene to the Late Pliocene, roughly 10-2 million years ago. Together with the North American giant Titanis walleri, it was among the last terror birds alive.[2]
The terror birds are usually classed together with birds such as cranes and rails in the Gruiformes, but this group will probably be thoroughly revised in the near future.
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[edit] Debate on Mesembriornis habits
A study called "Terror Birds on the Run" measured how fast ancient terror birds could run. It was found that a terror bird's average top speed was 50 miles or 70 km/h, this is not disputed heavily. However the speed of Mesembriornis is now heavily debated. This is probably due to the fact that the method of calculation was not as accurate as other mathematical methods, of course these methods are impossible because, like other terror birds, this beast's bones are fragmentary. There are two main theories about how Mesembriornis hunted:
"Crushing Kicks"
A group of scientists have suggested that terror birds had bone-shattering kicks. They may have used this kick to take down prey or defend kills. If it also attained the speed first thought as well as this kick, it could not have been forced off kills as easily as cheetahs in Africa.
"Cheetah of the Tertiary"
This school of thought suggests Mesmbriornis may have lived akin to a modern day cheetah, eating the smaller notoungulate mammals of the time (Miocene) using its speed to outrun the beasts. Its top speed is a matter of debate, but estimates go up to 90 kilometers per hour. Some other scientists like to scale down the predators speed to 85, 80, 75 or even the average phorusrhacid speed of 70 km/h
[edit] Footnotes
[edit] References
- Alvarenga, Herculano M.F. & Höfling, Elizabeth (2003): Systematic revision of the Phorusrhacidae (Aves: Ralliformes). Papéis Avulsos de Zoologia 43(4): 55-91 PDF fulltext
[edit] External links
http://news.nationalgeographic.com/news/2005/08/0801_050801_terrorbirds_2.html http://darrennaish.blogspot.com/2006/11/more-on-phorusrhacids-biggest-fastest.html http://www.journals.royalsoc.ac.uk/content/a9req1kl5wfc1kl4/ http://dubitable.com/?q=aggregator&page=15&from=100 Note the last article could not be found, however it states that Mesembriornis was six feet or 2 meters tall in the beginning segment presented by the search engine. Once examined it was confirmed that this was not two separate articles but a single article.
