纪录片《进化缺环》 第25期 对文塔螈的分析(2)

If we look at the tetrapod we have the pit now gone altogether

我们再看一下四足动物，凹陷已经彻底消失

and here's that lower blood vessel hole there in the tetrapod,

这里有个四足动物颚骨的下行血管出口

so in this respect livoniana kind of agrees with the tetrapod.

就这一点而言，文塔螈比较接近四足动物

On the other hand, we find that in the fish

另一方面，我们发现在鱼的颚骨上

a bone from the outer surface of the jaw comes round down to here and ends

颚外面有一块骨头向下延伸，到这里就结束了

and it's, it abuts against another bone up here called the pre-articular.

与之毗邻的这块骨头叫做前关节骨

In the tetrapod, the bone from the outer face comes all the way up here.

在四足动物的颚上，外面的骨头一直延伸到这上面，

It forms a big tongue extending backwards so and it comes all the way up here beneath it, so quite a different arrangement.

形成巨大的舌床，从后面开始，一直延伸到这下面，所以是很不一样的结构

Livoniana here has got the junction and the bone exposed on the surface

文塔螈有接合部，骨头暴露在外面

just like the fish, so in this case livoniana agrees with the fish,

这和鱼很相似，就这点而言，文塔螈比较接近鱼

so as you can see depending on which characteristic you look at

因此，根据观察到的这些特征

it either lies sort of halfway between or it agrees with the tetrapod, or it agrees with the fish.

它处于二者之间，它或者比较接近四足动物，或者比较接近鱼，

Exactly what you would expect from an intermediate form.

正是人们期盼的中间物种

Ahlberg believes livoniana really is an elusive transitional form, almost exactly half fish and half tetrapod.

Ahlberg认为文塔螈确实就是难得一见的过渡型物种，几乎就是半鱼半四足类的动物

It is certainly the only fossil yet discovered that shows the process of change between the two actually taking place.

它是迄今发现的反映二者演变过程的唯一一块化石。