| 恐龙名称： |
半鸟(龙) |
| 拉丁文名： |
Unenlagia comahuensis |
| 恐龙体长： |
2.4米长 |
| 恐龙体重： |
?吨 |
| 恐龙食物： |
肉食 |
| 生存年代： |
9千万-8千5百万年前白垩纪晚期
|
| 生存地点： |
阿根廷巴塔哥尼亚 |
| 辨认要决： |
不详 |
| 恐龙种类： |
蜥臀目·肉食龙类 |
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来 历
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大猛龙是在Novas于1997年阿根廷发现的
属于Saurischia Theropoda Tetanurae Coelurosauria [Unnamed node] 
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简 介
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[A]有的科学家认为半鸟是大猛龙的幼年形态。因为半鸟的脚上也有钩爪。但需要更多的化石证据来验证这一观点。大猛龙只有很少的化石被发现（包括35厘米长的钩爪）。如果大猛龙属于猛龙类的话，那么他很有可能比犹他猛龙还大。他有可能是半鸟的成年形态。
[B]Despite the relatively late appearance of this dinosaur in
the fossil record (Upper Cretaceous), several features of Unenlagia
are more birdlike than in any other non-avian theropod so far discovered.
Unenlagia resembles Archaeopteryx in the morphology of the scapula,
pelvis and hindlimb. But several shared primitive features of the pubus,
ischium and hindlimb suggest that Unenlagia may represent the sister
taxon of the Avialae (=Aves). The structure of the forelimb suggests
that the avian mode of the forelimb folding, and the extensive forelimb
elevation necesssary for powered, flapping flight, was already present
in cursorial, non-flying theropod dinosaurs. Unenlagia does resemble
Archaeopteryx in important details of its forelimb and hip. Foremost
among these is the structure of the shoulder joint, which indicates
that the animal could hold its arm directly outward, like a bird, as
well as fold it against its body.
This posture suggests that it could flap its arm, although Unenlagia
was much too heavy to fly with such a short wing. The skeleton of a
different and smaller animal will soon be described which is more complete
and may contain dromaeosaurid specializations in the foot and tail.
It is from strata that are slightly younger than those in which Unenlagia
was found.
Were these animals basal birds? No, for they lived at a
time when small, highly aerodynamic birds had been in existence for
several tens of millions of years. But they probably resembled the true
basal birds, which may have been present during middle Jurassic time,
80 million years before Unenlagia was alive.
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