What are Saurischia and Ornithischia?
The chief difference between the two major groups of dinosaurs is in the configuration of the pelvis. Seeley established the two dinosaurian orders and named them Saurischia (“lizard hips”) and Ornithischia (“bird hips”) in 1887; this differentiation is still maintained.
What are main the differences between Saurischia and Ornithischia?
Saurischians and ornithischians are the two groups of dinosaur, defined in terms of pelvic structure. Saurischians, whose name means “lizard-hipped,” had a pelvic structure more similar to that of modern lizards, while the ornithischians (“bird-hipped”) had a pelvic structure more like modern birds.
Who coined the terms Saurischia and Ornithischia?
The term “Dinosauria” was invented by Sir Richard Owen in 1842 to describe these “fearfully great reptiles,” specifically Megalosaurus, Iguanodon, and Hylaeosaurus, the only three dinosaurs known at the time.
What were the first three members of Dinosauria?
Dinosauria is comprised of three major clades: Ornithischia, Sauropodomorpha, and Theropoda. Traditionally, sauropodomorphs and theropods were recognized to form a clade Saurischia.
Is Saurischia an order?
In 1888, Harry Seeley classified dinosaurs into two orders, based on their hip structure, though today most paleontologists classify Saurischia as an unranked clade rather than an order.
Did dinosaurs have hips?
Most dinosaurs had one of two types of hip structures: the bird-hipped or the lizard-hipped. The hip structure allowed the dinos to move in certain ways and supported the type of eating it did. It could be that the hips were the start of it all.
Are Stegosaurus saurischians?
Towering giants such as Tyrannosaurus rex and Apatosaurus are both saurischians, but many plant-eating dinosaurs, including Triceratops and Stegosaurus, are classified as ornithiscians—which means bird-hipped—because their pubis bone was originally thought to resemble that of birds.
Are birds saurischians?
All carnivorous dinosaurs (certain types of theropods) are traditionally classified as saurischians, as are all of the birds and one of the two primary lineages of herbivorous dinosaurs, the sauropodomorphs.