【1】请问句中的 'they came from' 是插入语吗？

不是插入语，是省掉that/which的定语从句，they=the fossil teeth，先行词时the animal。

【2】 'an Iguanodon' 是 the animal 的宾补吗？

是。call +宾语+宾补，V+ n+ n结构。

【3】作者为什么不直接写成he called the animal an Iguanodon they came from? 而把the came from放在中间？请问这是什么写作手法？很少见。

有的工具书说：语法关系密切的两个句子成分被其它句子成分分隔开的现象，叫做分隔(splitting)。分隔主要是受两个原则的支配：一是尾重原则(the principle of end-weight)，二是句尾信息焦点原则(the principle of end-focus)。

就网友这个例子属于“宾语与宾语补语”被（定从they came from）分隔，支配原则是句尾信息焦点，即宾补an Iguanodon是新信息；而they（= the fossil teeth） came from是上文已经出现或暗示出的信息。

再如： 　　　　

In fact， radium not only damaged their health but also made the laboratory equipment with which they were working radioactive.　事实上，镭不仅损害了他们的健康，而且还使他们工作的实验设备具有了放射性。

其他的类型的分隔还有：

A.主语与谓语被分隔

 　　　　英语句子的主语与谓语一般都挨得很紧，它们之间很少插入介词短语等比较长的结构。但是，在较少的情况下，或是为保持句子的平衡，避免头重脚轻，或是为了语义严密，结构紧凑，在主语和谓语之间有时也会插入其它的成分。

 　　　　1.The resistance experienced when one body moves over another， with which it is in contact， is called the frictional force.　当一个物体在和它相接触的另一个物体上移动时所受的阻力，叫做摩擦力。

 　　　　2.Galileo asserted that “...any velocity once imparted to a body will be rigidly maintained as long as there are no causes of acceleration or retardation.”　伽利略断言，“……任意大小的速度一旦给予某一物体，只要没有加速或减速的原因出现，就将保持不变”。

 　　B.定语(或定语从句)与其中心词被分隔

 　　　　1.The time had come to decorate the house for Christmas.(CGEL)　已经是为了圣诞节来装饰房间的时候了。

 　　　　2.Batteries produce electron flow by chemical means—that is， chemical reactions take place inside the battery that result in a flow of electricity.　电池靠化学方法产生电子流——也就是在电池内发生化学反应，形成电流。

 　　　　3.A number of cars are already on the road powered by gas turbines.　一些以燃气轮机作动力的汽车已经出现在路上。

 　　　　4.The Prime Minister's decision was welcomed over the country to raise the wages of the workers and reduce the price of food.　首相提高工人工资和降低食品价格的决定受到全国一致的欢迎。

 　　　　5.When reports came into London Zoo that a wild puma had been spotted forty-five miles south of London， they were not taken seriously. (New Concept English， Book 3， L.1)　伦敦动物园曾接到报告，说在伦敦南部45英里的地方发现一只美洲野狮，但当时这些报告并没有受到重视。

 　　C.某些词语与其所要求的介词被分隔

 　　　　This book should therefore be useful in an advanced undergraduate course in nuclear physics， to engineers interested in the large-scale application of nuclear physics.　因此，在核物理学方面的高年级大学生课程中，这本书想必对关心核物理大规模应用的工程师们是有用处的。

 　　D.动词与其宾语被分隔

 　　　　1.We might bear in mind when we pass a big building or see an airplane or a car that we are looking at the fruits of man's labor in this tradition.　当我们经过一幢大楼或是看见一架飞机或一辆汽车时，我们必须记住，我们所看到的正是人类劳动在这一传统中创造出来的成果。

 　　　　2.The primary aim of the present book is to supply for students beginning the study of Theoretical Mechanics a course of such a nature as shall emphasize the fundamental physical principles of the subject.　本书的主要目的就是为开始学习理论力学的学生们提供一本教材，其特色是着重介绍这一学科的基本物理原理。

 　　E.介词与其宾语被分隔

 　　　　A car speedometer and a clock can be used to measure velocity as a function of time for (provided it only moves forward)a moving car.

 　　　　用速度表和时钟可以为一辆运动着的汽车(假定它只是向前行驶)测定其作为时间函数的速度。

 　　F.同位语从句与其先行词被分隔

 　　　　1.After Galileo's work the feeling grew that there were universal laws governing the motion of bodies and that these laws might apply to motion in the heavens as well as on earth.　在伽利略的工作以后，这样的认识加强了，即认为存在着支配物体运动的普遍规律，这些规律不仅支配着地球上的而且也支配着天体上的物体的运动。

 　　　　2.The question sometimes comes to my mind whether it was worth the effort.　有时我想到这样一个问题：是否值得花这么大气力。

 　　　　3.An order has come from Berlin that no language but German may be taught in the schools of Alsace and Lorraine.(The Last Lesson)　从柏林来了命令，阿尔萨斯和洛林地区的学校里，只准教德语一种语言。

牛津高级上有 call: 

(b) consider (sb/sth) to be; regard as 认为 某人[某事物] 是; 看作: 

I call his behaviour mean and selfish. 我认为他的行为卑鄙﹑ 自私. 

I would never call German an easy language. 我认为德语可不容易学. 

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So he called the animal they came from an Iguanodon.

= So he called the animal an Iguanodon (which) they came from.

1. 请问句中的 'they came from' 是插入语吗？  是定语从句

2. 'an Iguanodon' 是 the animal 的宾补吗？ 是

这里的call应该兼有  认为与命名 的含义