Saurischian: dinosaur order.
Ornithischian: dinosaur order.
Theropod: dinosaur suborder. From Encyclopaedia Britannica,
Theropod, any member of the dinosaur subgroup Theropoda, which includes all the flesh-eating dinosaurs. Theropods were the most diverse group of saurischian (“lizard-hipped”) dinosaurs, ranging from the crow-sized Microraptor to the huge Tyrannosaurus rex, which weighed six tons or more.The therapods were the oldest group of dinosaurs; they were the first to appear after the ur-dinosaur descendants split into two groups. See Foster's rule.
At the time of Louis Jacobs' book on Texas dinosaurs, c. 1995, there was one questionable T. rex fossil.
The largest number of T. rex fossils; the best preserved; and the largest T. rex specimens have come from the Williston Basin, straddling the North Dakota / Montana state line.
Connecting the dots, there is a very, very good chance that Pangaeac dinosaurs first appeared in what is now western North Dakota / eastern Montana. If so, the two most likely spots where theropods first appeared were in, what is now, northeastern Montana or southwestern North Dakota.
Dinosaur taxonomy, from infoplease;
Dinosaurs (“terrible lizards”) belong to a large group of reptiles called Archosauria (“ruling reptiles”).
They are classified into two distinct orders, which are distinguished by their pelvic differences.
Saurischia
All Saurischian (“lizard-hipped”) dinosaurs had modern lizardlike pelvises and clawed feet. Saurischians roamed Earth from the Middle Triassic to the end of the Cretaceous period. They included carnivores and herbivores. Members of the order included Allosaurus (“different lizard”), Apatosaurus (“deceptive lizard”), which was formerly called Brontosaurus, and Tyrannosaurus (“tyrant lizard”). The group is divided into two suborders: Theropoda (“beast footed”) and Sauropodomorpha (“lizard-footed forms”). Velociraptor (“swift robber”) was a theropod.
Ornithischia
All Ornithischian (“bird-hipped”) dinosaurs had pelvises similar to those of modern birds, and hoofed toes. All were herbivores. These dinosaurs lived throughout the world from the Middle Triassic to the end of the Cretaceous period. Members of the order included Iguanodon (“iguana tooth”), Stegosaurus (“plated lizard”), and Triceratops (“three-horned face”). The order is divided into four suborders: Ornithopoda (“bird footed”), Stegosauria (“plated lizards”), Ankylosauria (“armored lizards”), and Certopsia (“horned faces”).So,
- Class: Reptilia
- Subclass: Archosauria
- Orders:
- Order: Saurischia (never completely died out; lived on as sparrows)
- Suborders:
- Theropoda
- Saurpodomorpha
- Order: Ornithischia (completely died out)
- Suborders:
- Ornithopoda
- Stegosauria
- Ankylosauria
- Certopsia
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Amazon
Wow, what a great country. Every credit card company generates "cash back." One can argue ad nauseu which card is better. Soon, Apple will be releasing its own eponymous titanium card. Why wouldn't one have the Apple card in one's wallet.
Be that as it may, I find it incredible. I definitely spend more than I would if I didn't have a credit card. I assume that is true for 99% of credit-card carrying Americans.
Consciously I refuse to do it, but subconsciously there's no question in my mind that when I'm on the fence to buy something, the fact that I get 1 to 5% cash back carries the day; the decision is easy to make. Why not?
Because Amazon is where I do most of my on-line shopping, I most often use my Amazon-branded credit card when shopping.
I haven't bought a book at Amazon in quite some time. Six books are in "my cart" but I haven't been ready to purchase for quite some time. Today, I finally decided I just had to have my own copy of Louis Jacobs' Lone Star Dinosaurs. I massaged "my cart"; moving three books to "save for later" and ordering three books. Cash back paid for all three books and I still have more than enough in "cash back" to order more books later.
I think that amazing.
The books will arrive tomorrow.
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