Dinosaur Family Tree-Saurischians Part 2

Abelisaurs are a branch that includes such dinosaurs as ceratosaurs (which are also put into their own broups sometimes) and carnotaurus. They had short, four-fingered hands with various boney head ornaments on the skull. Carnotaurus having extremely stunted arms and two horns over each of its eyes. Ceratosaurus is recognizable from it's large blade-like horn over its nose. This group were quite large growing between 20 and 30 feet in length.

The next branch we see is the tyrannosaur branch made famous by, you guessed it, Tyrannosaurus rex. For years, considered one of, if not the biggest flesh-eating dinosaur to have ever walked the earth. Despite its impossibly small arms (about the size of an average man's, but much stronger), it was most likely a menace during its time on the planet with its huge head and large teeth (each about the size of a large banana).

Dromaeosaurs, our next branch, has another famous famous representative, velociraptor. The book and film Jurassic Park made the velociraptor a household name. Although depicted much larger in the film, they were actually about 6-7 feet long and about 3 feet high at the hips. Dromaeosaurs were mostly known for the dangerous second toe claw on its hind feet. The claw was curved and much larger than the others. It is widely though to be used in gutting its victims.

Spinosaurs were another large group of bipedal meat-eaters. Their main characteristics were a crocodile-type head and some having elongated back spines, in the case of Spinosaurus. Spinosaurus is sometimes considered to be the largest meat-eater ever. Some estimates put it at over 50 feet in length. The main diet is believed to be fish from due to the shape of the head, teeth, and jaw structure. Although, at 50 feet long, Spinosaurus could probably eat whatever it wanted!

Troodontids, considered to be the most intelligent of all dinosaurs, were mostly about half the size as a man and had huge eyes that faced forward to form binocular vision. Represented by Troodon, they also had large, long-fingered hands with partially opposable thumbs. This meant, like humans, it could easily grip and hold on to things. It aslo had the "sickle  claw" that dromaeosaurs had.

Now we begin to see some odd shapes starting to evolve. Ornithomimosaurs were called the bird mimic dinosaurs. Most had the appearance of a plucked ostrich. They came in various sizes abut all had the same basic shape. Some members of this group are Ornithomimus, Struthiomimus, and Garudimimus.

Therizinosaurs were like a nightmarish practical joke. They were some of the oddest looking dinosaurs ever. They had long necks, huge, oversized claws on their hands, pot bellies, and some, like Therizinosaurus, grew to a length of almost 40 feet. What made them even more strange was the fact that they were most likely plant eaters.

Continuing on with the strangeness, oviraptors were another odd looking group. They were very bird-like in they appearance. They had crests on their heads of various sizes. Many scientists believe theses crests might have been brightly colored. Oviraptor, this groups representative, was discovered with a number of eggs. Believing the animal was stealing and eating the eggs from another dinosaur and got its name which means egg thief. Later on, it was discovered that it was actually oviraptor's eggs and the dinosaur was protecting them. So, in actuality, the name is all wrong for this dinosaur and its group.

The next group in our theropod tree is alvarezsaurs. They were about 6 feet long most of which was taken up by it's tail and some of the most bird like of all the dinosaurs. Right around here, things start to get pretty complicated with trying to place a lot of the bird-like dinosaurs. In fact, to many scientists, the final branch for theropods ends with Aves, or birds.

When many people ask about dinosaur extinction, many scientists say birds are dinosaurs so they have never really gone extinct.

Next-Dinosaur Family Tree-Saurischians Part 3.