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The Deinosauria
A look into the Jurassic

Welcome to my deinosaur part of the site. Now now this area is not like other deino sites on the web. I'm not just going to talk about Tyrannosaurus rex and how it's sooo coool.

No I intend to go a bit farther than that. I want to show everyone the amount of diversity the deinosauria attained before their climactic ending 65 mya.

But first I'd like to cover some basic points on the deinosauria

What's in a name?

Come now surely some of you have been asking this since you first caught a glimpse of it. Why am I spelling dinosaur as deinosaur? The answer is really simple enough. Because that was how it should have been orignally spelled back when Sir Richard Owen first named them back in 1842.

Now the name, literally translated, means "Terrible Lizard." Yeah I know it all sounds like redundant info as of yet, but bare with me cause it gets better.

Due to this name of "terrible lizards" deinosaurs were soon looked at as these huge evil, slow and sluggish beasts. The fact that they no longer existed stood as proof that their "cold-blooded" and inferior bodies couldn't adapt and therefore were evolutionary throwbacks. Loose ends that made good examples of what not to be.

Funny how translations work.

See the truth is when Sir Richard orginally named them, he was already convinced from the scant remains that these were no lizards. Yet lizard was a common reptile that everyone new of, so since he was convinced that they were reptilian he went ahead and used a Greek name for reptile which was sauros meaning lizard (the real Greek name is herpes, but I guess he didn't like the ring of deinoherps and so didn't use it.). So what Sir Richard meant wasn't "terrible lizards" but "terrible reptiles."

Okay that's the first part, now onto the second.

When Sir Richard gave the name deinosaur to these creatures, he didn't mean them as "terrible lizards" or "terrible reptiles" as it were. The word terrible meant something completely different from what it does now. He didn't consider them evil beasts (well possibly, but that wasn't why he gave the name). He looked at these huge animals and wanted to give them a worthy name. Something to show off their enormous sizes. So he used the Greek deinos which of course translates to terrible, but actually means great or awesome.

So the real definition of Sir Richard Owen's term deinosaur isn't "terrible lizard" but "Great reptile." Now doesn't that make a whole lot more sense.

So why, do you ask, is it that people call them dinosaurs and not deinosaurs? Well, it might have had a lot to do with simplicity. Much like how Americans eliminated the vowel ou in words like colour and humour, Owen might have simply eliminated the e for no other reason than to make the word shorter.

Now awhile back a friend of mine on the net had brought this to my attention. Well I thought about it and considered it, saying "well that's an interesting bit of info", but never really using it. After all it's hard to drop a name you've grown up with. It wasn't until I actually put some more thought into it that things started to make more sense. Just think about all the other deino names. There's: Deinonychus (Great claw) Deinocheirus (Great hand) and Deinosuchus (Great crocodile) along with many others. And each one is used to describe a huge animal or part there of. So after taking notice of that, I decided that the term deinosaur is just as correct, if not more, as dinosaur. So now for the most part I use deinosaur with an E in most of my writings on them. Unless there is a reason to drop the E I won't.

And suddenly it all makes sense.


All the members of the deinosauria are grouped under the superorder or subclass depending on your preference DEINOSAURIA. This is then split into the actual two orders: SAURISCHIA and ORNITHISCHIA. Then all this is put into many other nit picky orders until eventually a T.rex pops out. Well not exactly.

There will be more on this later. This bit was just to let every novice and up know that all the deinosaurs fit into one category after all.


The two orders of deinosaur are based on the arrangement of their hips.

One form involves the ischium and pubis(lower halves) of the hip bone split in two directions. The pubis extends in front and ends in a large projection called the pubic boot. This group is known as the saurischians or "lizard hipped" (or reptile hipped) deinosaurs. This is because their hips are like those of other reptiles. This group has some of the most common deinosaurs like T.rex and Apatosaurus ajax (used to be known as Brontosaurus). It is also the group that paleontologists believe birds came from.

The second hip form is that in which the ischium and pubis head in the same direction. Both head down towards the tail and end in a thinning of bone. No boot. This term is known as the ornithischia or "bird hipped" deinosaurs. This is based on the superficial resemblance that this hip has to a bird's. But birds are actually modified saurischians (more on that later.) This new hip arrangement allows the gut to extend deeper into the body which is great for a herbivorous deinosaur. So far all ornithischians are herbivores. The ornithischia is home to such famous deinos as Triceratops horridus and Stegosaurus stenops.


The last thing that I'll have here (for now) is on the deinosaurian stance. See deinosaurs are archosaurs and as archosaurs they share some common things, such as:
  1. A mandibular fenestrae (hole in lower jaw)
  2. An antorbital fenestrae (hole inbetween eye and nose)
  3. Socket teeth (teeth that fit inside holes in the jaw instead of cemented to the sides)
  4. And an erect stance (most archosaurs)

The last one is the big one. Most archosaurs had erect stances. Now an erect stance is something that has evolved in numerous animals. In mammals it involved the rearrangment of the hip bones so that the legs fit right inside it. In birds, deinos and crocodylians it evolved by means of a simple hole in the hip socket. This hole allows the legs to fit into the hip and go directly underneath instead of out to the side. This is helpful (but not required) for big animals and is also good for being able to breathe while walking. See in certain reptiles, like lizards, the movement of the legs forces compression of the rib cage and makes it unable for the lizard to breath and move at the same time. So when they walk they do it anaerobically (no oxygen). By having an erect stance the legs don't usually interfere with the flow of air and thus let the animal breathe while walking, or move aerobically (with oxygen).

So having an erect stance, deinosaurs were able to move and breathe at the same time.


The classification of the deinosauria is a very confusing thing. Since they have been dead for tens of millions of years, it is much harder to divide them up into species. Families also change. So for now I have them all grouped under their respective suborder. More to come.

Suborders of the Deinosauria
Theropoda = The meat eating deinosaurs ( Tyrannosaurs, Allosaurs, Dromeosaurs etc.)
Sauropodomorpha = The large long necked deinosaurs (Apatosaurs, Brachiosaurs etc.)
Ornithopoda = The duckbilled hadrosaurs and others (Hadrosaurs, Hypsilophodonts etc.
Thyreophora = The armored deinosaurs (Ankylosaurs, Stegosaurs etc.)
Marginocephalia = The horned deinosaurs and bone heads (Triceratops, Pachycephalosaurs etc)