AY Honors/Dinosaurs/Answer Key

1. What does the term dinosaur mean? Who used that term for the first time?

The word Dinosaur is a Latinized combination of the Greek roots “deinos” [terrible] and “sauros” [lizard] - so the word means Terrible Lizard. Sir Richard Owen, a British anatomist and taxonomist, coined the term in the early 1840s after determining that a set of fossil bones he studied, including those of Iguanodon and Megalosaurus, were not lizards, but something uniquely different.

2. Discuss how scientists figure out what live dinosaurs may have looked like, considering that they may have had only a small number of bones / evidence to base their reasoning on.

One of the first steps in dinosaur reconstruction is comparative anatomy. Because bones often have analogous features, functions and articulation, paleontologists can make a first set of assumptions about the size, shape and gait of the dinosaur, even with only a small number of bones. Close investigation of bones can reveal signs of muscle attachment, which can further give shape to the dinosaur. Paleontologists also use comparative anatomy to see basic forms of animals in similar environments, using clues from the rock and other fossils around the dinosaur bones to infer a particular ecosystem, and looking at modern animals that live in similar ecosystems for potential models. In some cases, impressions of skin and feathers can offer some clues as to the external appearance. Although there is no fossilization of color, paleontologists can draw some inferences from patterns and colors in modern animals that live in similar ecosystems or have similar lifestyles.

3. Explain or discuss the following within a group or to an instructor

d. What types of skin did dinosaurs likely have? Give species examples of each.

Although much rarer than fossilized bones, skin prints from dinosaurs have also been found in the fossil record. Many prints highlight bumpy skin, small or large non-overlapping scales and in some species bony plates. Hadrosaurs have some of the best preservation of skin prints, showing non-overlapping bumpy scales, sometimes nearly hexagonal in shape. Dinosaurs like Stegosaurus had bony plates on their skin, possibly for protection, thermoregulation, sexual advertising or a combination of the three. The Ankylosaur had osteoderms - bony projections and plates - embedded its its skin that provided a complete armor coating.

e. What are the sauropodomorphs?

Dinosaurs are in general divided into two groups, the Ornithischians (“Bird-Hipped” dinosaurs, all herbivorous, including well-known kinds such as Triceratops, Stegosaurus, and Hadrosaur), and the Saurischians (“Lizard-Hipped” dinosaurs) which are divided into two main groups, the Theropods (“Beast-Footed” Dinosaurs, such as Tyrannosaurus Rex and Deinonychus) and the Sauropodomorphs (“Lizard-Foot Form” Dinosaurs), which include the largest of the land animals, such as Diplodocus, Seismosaurus and Apatasaurus.

f. In which two groups are they divided?

Sauropodomorphs are divided into two categories. The smaller prosauropods (“Before Lizard-Foot” Dinosaurs), were mostly herbivorous bipedal early dinosaurs from the Late Triassic to Early Jurassic, including Saturnalia and Thecodontosaurus. The larger Sauropods (“Lizard-Foot” Dinosaurs) in some cases grew to massive size, and were characterized by long necks and tails, relatively small heads, primarily a quadrupedal gait, and a generally herbivorous diet. Sauropods include Apatasaurus (once called Brontosaurus), Brachiosaurus, and Saltasaurus.