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an ovoraptorosaurian (egg snatcher) theropod dinosaur from the Late Cretaceous of Asia.
Pronunciation: av-ee-MEE-mus
Meaning: Bird mimic
Author/s: Kurzanov (1981)
Synonyms: None known
First Discovery: Gobi Desert, Mongolia
Chart Position: 228

Avimimus portentosus

Not to be confused with Ornithimimus which was also a "bird mimic"—but from the Greek "ornithos" (bird) rather than the Latin "avis" (bird)—Avimimus is one of the oldest, most primitive oviraptorosaurs (egg snatchers) and was the first known theropod dinosaur to sport such a large number of features in common with our modern flying friends.

Upon discovery, Sergei Kurzanov pointed to its feet with three forward-pointing toes, fused hand bones, and a toothless parrot-like beak, but mostly to a ridge and quill knobs on its ulna that may (or may not) have anchored feathers, and was convinced that Avimimus was capable of weak flight. Given an almost horizontally-oriented ilium that made it look kind of fat, plus short arms and a lack of load-lightening hollows in its vertebrae to house air sacs, the chances of flight are less than slim. But extremely long and slender legs with longer shins than thighs suggest that it could run fast, despite its rotund appearance.

Avimimus had a long and slender neck with much longer vertebrae than those of other oviraptorosaurs. Its skull was small compared to its body, but its eye sockets and braincase were large, and later discoveries showed that its jaws, initially reported as toothless but with "tooth-like projections" along the front edge, contained a few small teeth, suggesting omnivory. Because of its weird combination of features, Avimimus was nominated to anchor its own family (Avimimidae) by Kurzanov who thought they were closely related to birds, more so, in fact, than Archaeopteryx aka Urvogel (meaning "first bird"). However, Archaeopteryx is closer, "they" turned out to be "it" as Avimimidae failed to recruit any further members, and Avimimus has since been moved to Caenagnathidae.
Avimimus is derived from the Latin "avis" (bird) and the Greek "mimos" (mimic).
The species epithet, portentosus, in Latin, means "unusual" but not just unusual; profoundly and unspecifiably unusual, resulting in exciting wonder and awe.
The first remains of Avimimus were discovered in the Djadokhta Formation at Udan-Sayr, 75 km south of Hovd-somon Ubur-Hangayskaymak, in the foothills of the Gurvan-Sayhan mountain range, Mongolia, in 1973 by a Joint Soviet-Mongolian paleontological expedition, who also discovered remains in the Shara-Tsav location, 7 km north of the Bayshin-Tsav in the southeastern Gobi. Or so we were led to believe. When Watabe and colleagues described a new specimen in 2006 they reckoned that all remains more likely hail from the younger Nemegt Formation. The holotype (PIN 3907/1) is an incomplete skeleton.
Era: Mesozoic
Epoch: Late Cretaceous
Stage: Campanian
Age range: 84-71 mya
Est. max. length: 1.5 meters
Est. max. hip height: 0.8 meters
Est. max. weight: 8 Kg
Diet: Omnivore
• S.M. Kurzanov (1981) "An unusual theropod from the Upper Cretaceous of Mongolia". Iskopayemyye pozvonochnyye Mongolii (Fossil Vertebrates of Mongolia). Trudy Sovmestnay Sovetsko-Mongolskay Paleontologiyeskay Ekspeditsiy (Joint Soviet-Mongolian Paleontological Expedition) 15:39-49.
• P. Vickers-Rich, L.M. Chiappe, S. Kurzanov (2002) The enigmatic bird-like dinosaur Avimimus portentosus" in "Mesozoic Birds: Above the Heads of Dinosaurs".
• P. Currie, N. Longrich, M. Ryan, D. Eberth, B. Demchig (2008) "A bonebed of Avimimus (Dinosauria: Theropoda) from the Late Cretaceous Nemegt Formation, Gobi Desert: Insights into social behavior and development in a maniraptoran theropod". Journal of Vertebrate Paleontology, 28(3): 67A.
• John Long and Peter Schouten (2009) "Feathered Dinosaurs: The Origin of Birds".
• Watabe, Suzuki and Tsogtbaatar (2006) "Geological and geographical distribution of bird-like theropod, Avimimus in Mongolia". Journal of Vertebrate Paleontology. 26(3), 136A-137A.
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To cite this page:
Atkinson, L. "AVIMIMUS :: from DinoChecker's dinosaur archive".
›. Web access: 25th Mar 2017.