The Dinosauria
A look into the Jurassic
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Dinosaurs, the quintessential reptiles. The pinnacle of reptilian evolution...or so it is usually told. No reptile holds the imagination of humans more than the dinosaurs. From their huge size to their astounding diversity, the dinosauria was a extremely intriguing branch of reptilian diversity.

There will be more coming to this site soon, including info on the great "warm-blooded vs. cold-blooded" debate, along with a look at birds and why they should, or shouldn't be called living dinosaurs.

For now, though, we will just go over some basic points.

What's in a name?

The term dinosaur was first coined by Sir Richard Owen back in 1841/1842. The name, literally translated, means "Terrible Lizard." This probably seems like redundant information right now, but it does get better.

Due to the name "terrible lizards" and the fact that they were looked at as huge reptiles, dinosaurs were seen as these huge, lumbering, 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.

Well actually there is more to this. Owen, Huxley and other early dinosaur workers originally saw them as being highly active animals, equivalent to today's birds and mammals, yet they didn't consider them to be warm-blooded. More on this intriguing view of dinosaurs later; for now though, back to the story.

It got lost in the translation.

When Sir Richard orginally named them, he was already convinced from the scant remains that these were no ordinary lizards. Work done by Thomas Henry Huxley and others seemed to confirm that dinosaurs were very different from the typical lizard. Yet lizard was the poster child for reptiles, 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 herpeton, but I guess he didn't like the ring of deinoherps and so didn't use it.). So what Sir Richard meant was not "terrible lizards" but "terrible reptiles."

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

When Sir Richard gave the name dinosaur 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. Terrible back then though, meant great or awesome.

So the real definition of Sir Richard Owen's term dinosaur isn't "terrible lizard" but "Great reptile" (fearfully great reptile, if you want to be exact). Now doesn't that make a whole lot more sense.

Dino or Deino?

So, if the root word for dino is deinos, why aren't they deinosaurs instead of dinosaurs. After all there are plenty of prehistoric animal names already that use it, such as: Deinonychus (Great claw) Deinocheirus (Great hand) and Deinosuchus (Great crocodile). 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. Maybe even to make the name more unique.

In truth, the term deinosaur is more correct than dinosaur, just as how the term ceratopian is more correct than ceratopsian, but since dinosaurs are so well known, adding the e into the name might cause more confusion than needed. Furthermore, unlike ceratopian, deinosaur has never been used in an official, taxonomic, sense.

Still if the reader comes across the use of the term deinosaur in place of dinosaur on this site, or others, they will at least know why.


All the members of the dinosauria are grouped under the superorder or subclass depending on your preference DINOSAURIA. 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.

As one goes further throughout this portion and other portions of the site dealing with extinct animals, one will notice that the Linnean system of classification starts to falter. The deeper we go into phylogenetics, the harder it is to abide by Linnean rules and so a new form of classification will have to be used. This form is known as cladistics. More on this later.


The two orders of dinosaur 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) dinosaurs. This is because their hips are like those of other reptiles. This group has some of the most common dinosaurs like T.rex and Apatosaurus excelsus (used to be known as Brontosaurus). It is also the group that paleontologists believe birds evolved 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" dinosaurs. 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 dinosaur. So far all ornithischians are herbivores. The ornithischia is home to such famous dinos as Triceratops horridus and Stegosaurus stenops.


The last thing here for now, is a quick review on dinosaurian stance. Dinosaurs 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. A tri-radiate pelvis
  5. 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, dinos and many 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 large animals.


The classification of the dinosauria 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 they will all be grouped under their respective suborder.

More coming soon.

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