Osteology of Mesozoic Life Exercise
Academy of Natural Sciences
Working with your group mates, your goal for this exercise is to determine answers to the questions below.These are not easy—they require focus, careful observation, and discussion among group members (because each person’s eyes will likely pick up different things).
Record notes, and (if you wish) make sketches in the gallery.You will then discuss your findings with those of the other groups.
As homework, you will compile your notes into clear, organized typed answers.Use appropriate anatomical and directional terminology in your descriptions.
You will not be turning in your sketches.(Those are your own study aids and notes for future reference in later assignments.)
Questions:
- What are the ways in which you can distinguish vertebrae from different regions of the axial skeleton (cervicals vs. dorsals vs. caudals)?Use Deinonychus, Chasmosaurus, and Corythosaurus for this question.(Good views of the vertebrae of Corythosaurus can be found on the stairs and from the second floor balcony.)I am interested in how you would distinguish bones from different regions in the same animal.Don’t worry about comparing the animals to each other (yet).
- What are the ways in which you can distinguish caudal vertebrae of hadrosaurs(use Corythosaurus) from caudal vertebrae of ceratopsians(use Chasmosaurus)?
- What are the ways in which you can distinguish caudal vertebrae of theropods (use Tyrannosaurus) from caudal vertebrae of ornithischians (use Chasmosaurus and Corythosaurus)?You may need to go upstairs to get a good view of the Tyrannosaurus tail.
- Discuss how the morphology of ribs differs in the different regions of the axial skeleton (cervical vs. dorsal vs. caudal).Consider both the morphology of the ribs themselves and the ways in which they articulate with the vertebrae.Use Tenontosaurus and Chasmosaurus for this question.
- Consider the latticework of rods along the spine of Corythosaurus.What are these rods?How would you distinguish them from rib sections if you found them broken and isolated in the field?
- What are distinguishing features of each of the six major limb bones (femur, tibia, and fibula in the hindlimb; humerus, ulna, radius in the forelimb) that allow you to tell them apart?Consider both proximal and distal ends, as well as any prominent features on the shaft.In this question I want you to focus on general patterns that you can observe in all of the dinosaurs listed.Regardless of lineage or posture (quadrupedal vs. bipedal) there are commonalities.For the hindlimb bones, use Tyrannosaurus, Chasmosaurus, and Corythosaurus; for the forelimb bones, use those three as well as the forelimbs from both sauropods.
- Look at the long bones of the Deinonychus skeleton.Something should strike you as odd about the shapes of the bone shafts—what is it?And why are the bones like this?
- In general, how can you distinguish theropodmetapodials (that’s the general term for both metatarsals and metacarpals) and phalanges from those of ornithischians?Don’t forget that unguals are phalanges! (No specific critter suggestions here, it’s time to start remembering who is who.)
- What are the ways in which you can distinguish hand bones (metacarpals and manual phalanges) from foot bones (metatarsals and pedal phalanges).Consider both bipeds (Tyrannosaurus, Corythosaurus) and quadrupeds (Chasmosaurus).
- Describe the difference between the saurischian and ornithischian pelvis.(Yes, I know we’ve already talked about this; consider it practice in anatomical terminology.)Use Tyrannosaurus, Chasmosaurus, and Corythosaurus for this question.
- Is Stegosaurus (the reconstruction is upstairs) a saurischian or an ornithischian, and how can you tell?
- Compare the teeth in the skulls of Tyrannosaurus and Triceratops on the second floor.How do the shapes of the teeth correspond to the animals’ diets?