GEL 113 Homework 15 Answer sheet

Chapter 10: Saurischians (Part I. Theropods)

Part I: True or False:

1.F 2.T 3.F 4.T 5.T 6.F 7.F

Part II: Multiple Choice:

1.C 2.B 3.C 4.A 5.C 6.C 7.D 8.B 9.C 10.A 11.C

Part III:

1. a. basal, short-hipped theropods - diagnosed by a very short ilium and the presence of only two fully-fused sacral vertebrae.

b. ceratosaurs - diagnosed by fused pelvic bones lacking distinct sutures, a large ilium and five sacral vertebrae. They also retain a fourth finger, have an upper tooth row which extends posteriorly behind the rear margin of the antorbital fenestra, and a prominent "kink" in the upper jaw at the junction of the maxilla and premaxilla.

c. tetanurans - hands with three fingers or less, and a distally broadened pubis (pubic boot) are characteristic of tetanurans.
d. carnosaurs - diagnosed by three fingered hands, and an elongated, robust ischium.

e. coelurosaurs - mainly by a short ischium.

2. Carnosaurs have three fingers, Tyrannosauriids have two. Carnosaurs have a robust ischium about as long as the pubis, while tyrannosauriids have a gracile ischium shorter than the pubis. In carnosaurs the middle metatarsal contacts the ankle, whereas in tyrannosauriids the middle metatarsal is pinched off below the ankle. Tyrannosauriids have a robust skull and mandible, and a bone that protrudes into the lower temporal fenestra; while carnosaurs have a less massive skull with a thinner mandible, and the lower temporal fenestra is unobstructed.

3. Oviraptor was assumed to be an egg stealer because one specimen was found draped over a presumed Protoceratops nest, assumedly killed in the act of stealing eggs. More recently it has been shown that it was actually an Oviraptor nest, and that the animal probably died while guarding the nest, not stealing from it.

Return to Homework Mainpage

Return to Dino Home Page