The Difference Of Saurischia Versus Ornithischia
Although the general public like to think that researchers categorize dinosaurs based on being carnivorous or herbivorous, this is not the case. Dinosaur species are actually most commonly categorized as being saurischian or ornithischian. So what do these terms mean and how do they differ? Let’s take a look.
Understanding Saurischia Versus Ornithischia
The terms saurischia and ornithischia refer to the hip structure of a dinosaur species. Below we will take a look at the two types of dinosaur hip structure and how they can be distinguished from one another.
Saurischia Versus Ornithischia: Saurischia
The term Saurischia refers to dinosaurs with a “lizard hip” structure. Consequetly these dinosaurs are often referred to as lizard hipped dinosaurs. All carnivorous dinosaurs are saurischians in addition to Sauropodomorphs. Ironically, birds are descended from lizard hipped dinosaurs, more specifically, the Theropods.
Saurischian dinosaurs have a three pronged hip structure where the pubis points forwards.
Lizard hipped dinosaurs are so named because of the likeness of their hip structure to modern day lizards.
Subgroups of Saurischia include: Herrerasauridae (possibly) and Eusaurischia including Sauropodomorpha and Theropoda.
Saurischia Versus Ornithischia: Ornithischia
The term Ornithischia refers to dinosaurs with a “bird hip” structure. Consequetly these dinosaurs are often referred to as bird hipped dinosaurs. Ornithischians were herbivorous dinosaurs and were more numerous than saurischian dinosaurs in terms of population count.
Ornithischian dinosaurs have a hip structure where the pubis points backwards and runs parallell to the ischium. These dinosaurs also frequently have a forward pointing process as well which gives them the appearance of having a four pronged pelvis. Those four prongs come from the two rear facing processes and the two forward facing processes.
Superficially the hip structure of bird hipped dinosaurs is similar to that of birds, which is how these dinosaurs got their name. It is important however, to understand that simply because these dinosaurs are referred to as “bird hipped” does not mean that they are directly related to birds.
Subgroups of Ornithischia include: Eocursor, Fabrosaurus, Pisanosaurus, Taveirosaurus, Trimucrodon, Heterodontosauridae and Genasauria.
So when it comes to Saurischia Versus Ornithischia, which is your favorite dinosaur clade?