Mini-Assignment 6: Prepare for the next excavation lab (caudal bones and trace fossils)
To answer the questions below, read pages 226-231 about dinosaur trace fossils and see box 6.1 and page 341 for information about the skeletal regions you’ll seen
in lab this week.
1.
What trace fossil could serve as evidence that main dinosaur you are excavating was predated upon? (1 pt)
Tooth marks can serve as evidence of whether the species was a predator or prey.
2.
What evidence could you use to support that a given coprolite was made by a dinosaur? What might give you uncertainty about what animal made the coprolite? (2 pts)
You could use the size and/or mass of the coprolite to serve as evidence that it was made by a dinosaur. Due to the limited research and analysis of prehistoric coprolites, it is hard to decipher which species it came from. Since coprolites are relatively similar in size and content to other species, such as crocodiles, it gives uncertainty of where it came from.
3.
The ventral bones beneath the skeleton are called chevrons. What are the functions of chevrons? (1 pt)
The chevrons function as support and connectivity for the tail. They aid in stabilization/balance and give protection to the tail.
4.
What are the two types of bones represented in the caudal region of the organism’s skeleton? (1pts)
The two bones represented in the caudal region are the caudal vertebrae and the chevrons.
5.
Examine the figures of these dinosaur tails. You may need to be logged in to the library using your NetID and password to view some images. Describe the differences you see among the taxa using at least 5 of the following terms
: centrum
, neural arch
, neural spine
, transverse process
, chevron, osteoderm
, caudal, sacral (5 pts)
Ankylosaur:
https://journals.plos.org/plosone/article/figure/image?size=large&id=10.1371/journal.pone.0006738.g001
Titanosaur:
https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fsrep06196/MediaObjects/
41598_2014_Article_BFsrep06196_Fig1_HTML.jpg?as=webp
Spinosaur:
https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fs41586-020-2190-3/MediaObjects/
41586_2020_2190_Fig1_HTML.png?as=webp
Comparing the transverse process, the Ankylosaur and Titanosaur are more limited and located closer to the pelvis than the Spinosaurus. This could be due to a difference in habitat and function. The neural arch and neural spine of these species differ as well. The Ankylosaur has short and stubby neural spines, and the Titanosaur has taller neural spines compared to the Ankylosaur. In contrast, the Spinosaurus has long, thin neural spines. The Ankylosaur has a broader neural arch compared to the other two species. Another significant difference between the Ankylosaur and the other species is the presence of an osteoderm. Neither the Titanosaur nor the Spinosaurus have an osteoderm. The species differ in the shape and role of the centrum. The Ankylosaur has short, broad centra in order to support their armored tails. The Titanosaur has a more elongated centra and the Spinosaurus has a long, slender centra due to the surrounding environment.
