Lab 8 Excavation Stage IV
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Texas A&M University *
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Course
207
Subject
Geology
Date
Apr 3, 2024
Type
Pages
4
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DINOSAUR EXCAVATION STAGE IV
Excavation Stage IV- Skull and Forelimb
Below is “site map” image of the excavation site(s). These images, and others you will need to complete
this assignment, are available at:
https://sites.google.com/tamu.edu/geol-207-dinosaur-world-ex4/home
. Arrows within the images
indicate the direction of North. On your site map image, each bone has been numerically labeled.
Figure 1. Skull of mystery dinosaur.
Figure 2. Pectoral girdle of forelimb of the mystery dinosaur in close proximity to an oviraptor nest and
possibly a sauropod claw.
1)
Identify and Catalog the Bones:
Use Table 4 below to catalog the bones recovered during the
excavation.
For each numbered bone, you should identify the type of bone and the region of the
body the bone is from
(in this lab, all bones are from the caudal region).
Under notes, provide any
features present that are important sharded derived characters that could help you in your
identification. You should also provide an approximate measurement for each bone marked with a *
using the scale bars on the zoom-in photos available at
https://sites.google.com/tamu.edu/geol-207-dinosaur-world-ex4/home
.
Table 4. Bone catalog for Excavation Stage IV. (5 pts)
Bone
Number
Bone
Identification
Skeletal Region
Measurements
Other Notes
Length
(cm)
Width (cm)
106
Skull
--
--
107*
Skull
60
13
108*
Skull
68
30
109*
Pectoral Girdle
80
5
110
Pectoral Girdle
--
--
111*
Forelimb
36
6
112
Forelimb
--
--
113
Forelimb
--
--
114
Forelimb
--
--
115
Forelimb
--
--
116
Forelimb
--
--
117
Forelimb
--
--
118*
Forelimb
5
3
119*
Forelimb
11
3
120*
Forelimb
6
4
2)
Interpret the Skeleton (10 pts)
a.
Having identified the bones present in your specimen, list the order of the forelimb bones
starting with the bones that are most proximal to the body. (Note. d and e have the same approximate
placement). (
2 pts)
Terms to use: coracoid, phalanges, metacarpals, ulna, humerus, radius, unguals, scapula
a. Scapula
b. Coracoid (assuming it's present)
c. Humerus
d. Ulna
e. Radius
f. Metacarpals
g. Phalanges
h. Unguals
b.
Considering the order the bones would be present in the living animal, are the bones preserved
in approximately life position?
(1 pt)
It looks like the bones are preserved in an approximate life position.
c.
How many digits are on the manus (hand)?
(1 pt)
There are two digits on the manus.
d.
Describe the size/shape of the teeth in the organism. Make a claim about the feeding strategy of
this organism, list your evidence, and explain your reasoning.
(2 pts)
The teeth on this organism are sharp and they are all small but vary in size and are not uniform. The
feeding strategy of this organism is most likely carnivorous as sharp and small teeth are useful to
consume other creatures and herbivores usually have more flat and larger teeth.
e.
Count the number of teeth in each region of the skull: premaxillary, maxilla (upper jaw) and
dentary/mandible. (
2pts)
Premaxillary teeth:
4
Maxillary teeth:
14
Dentary teeth:
11
f.
What is the approximate length of the dinosaur?
Hint: You may need to sum the length of the
caudal region from Stage II, the length of the Spinal Region from Stage III, and the skull length from Stage
IV.
(2 pts)
Summing up the length of all of the regions, our dinosaur might be around 7.5 meters.
3) Evaluate your evidence to reach a preliminary identification (12 pts)
a)
Given your observations of the forelimb and skull, provide evidence supporting or refuting the claim
that the specimen belongs to an ornithopod dinosaur. Explain your reasoning.
(3 pts)
Based on my observations, this specimen is not an ornithopod. This is based on the teeth for the most
part, ornithopod are herbivores that graze and their teeth do not look like the sharp carnivorous ones
our organism has.
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b)
Given your observations of the forelimb and the skull, provide evidence supporting or refuting the
claim that the specimen belongs to a theropod dinosaurs. Explain your reasoning.
(3 pts)
Some evidence that supports this specimen belonging to the theropod dinosaurs could be that
they tend to have a reduced number of digits on each manus (2). Theropods are also carnivorous
and the size/shape of the teeth indicate that this organism is a carnivor because they are sharp
and small like a razor blade making it easy to tear through flesh.
c)
Suppose that this organism is a theropod dinosaur. Given the information in the table below
from Currie
et
al. (2003), what genus (or genera) could your dinosaur belong to?
(2 pts)
Based on the information in the table below, our dinosaur could belong to the following genera (our
organism is similar but not exactly the same): albertosaurus, nanotyrannus, and tyrannosaurus.
d)
Based upon your hypothesized genus identification from (c) and your size estimates, is the specimen
most likely a juvenile or an adult? Explain your reasoning.
(2 pt)
If the dinosaur was an Albertosaurus then the specimen is most likely a juvenile as an adult gets to be
around 9 or 10 meters long.
e)
Based upon your hypothesized genus identification from (c), what characteristics might you use to
make a species-level determination?
(2 pts)
Some characteristics you could use to make a species-level determination are the number of teeth,
digits, skull shape, and size of the dinosaur.