There are few known fossil specimens of these ancient snakes and only three in which the hind limbs are preserved and visible.
这些古老蛇类的化石标本非常稀少，仅有的三个标本的后肢保存完好并可见。
Most fossil specimens are little more than carbon impressions although distinctive shapes are known.
尽管清晰的形状已为人所知，但大多数化石标本只不过是炭质印痕。
The brain size in earlier fossil specimens was about 500cc but rose to 800cc toward the end of the species life period.
该化石标本脑容量在较早时曾升至约800cc的500cc，但对末的物种生命。
应用推荐