Lab5_Excavation Stage I (2)
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School
Texas A&M University *
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Course
207
Subject
Geology
Date
Apr 3, 2024
Type
Pages
5
Uploaded by AdmiralFogEchidna34
DINOSAUR EXCAVATION STAGE I Part I: Excavation Stage I - Pelvic Girdle and Hindlimb A new fossil site has just been excavated and you are on the team that must identify what has been found. In the next 4 laboratory assignments you will examine different portions of the skeleton and use anatomical clues to narrow down the possible identity the fossil. After completing all 4 assignments, you will be placed in groups to compare your evidence and create a consensus report on your findings. 1) Find Your Bearings.
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-
ex1/home
. An arrow is labeled in the top right corner of your image indicating the direction of North. On your site map image, each bone has been numerically labeled.
2) Identify and Catalog the Bones: use the Table 1 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 (for this lab, “hindlimb” and “pelvis” are appropriate terms for skeletal 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-ex1/home
. Table I. Bone catalog for Excavation Stage I. (5 pts) Bone Number Bone Identification Skeletal Region Measurements Other Notes Length (cm) Width (cm) 1* 2* 3 -- -- 4* 5 -- -- 6 -- -- 7 -- -- 8 -- -- 9 -- -- 10 -- -- 11 -- -- 12 -- -- 13 -- -- 15 -- -- 16 -- -- 17 -- -- 18 -- -- 19 -- -- 20 -- -- 21 -- -- 22 -- -- Hindlimb
80
20
Femur
70
10
Hindlimb
Tibia
Two separate balls at the end of bone that are classified as two separate bones
Fibula
Hindlimb
Skinnier bone of the hindlimb
Tarsometataursus
Hindlimb
50
10
Biggest bone with the phalanges
The largest bone of the three longer ones
Dewclaw
Hindlimb
Smallest claw separated from other claws
Phalange
Hindlimb
Pelvic
Pelvic
Pelvic
Hindlimb
Hindlimb
Hindlimb
Hindlimb
Hindlimb
Hindlimb
Hindlimb
Hindlimb
Hindlimb
Hindlimb
Hindlimb
Hindlimb
Ungual
Ungual
Phalange
Phalange
Phalange
Phalange
Phalange
Phalange
Phalange
Phalange
Astragalus
Calcaneum
Pubis
Ischium
Ilium
Longer and straight edged
Posterior orientation- Saurischian
Has a serrated edge along the bottom
3) Interpreting the Skeleton (7 pts)
a)
Having identified the bones present in your specimen, list the order of the hindlimb bones starting with the bones that are most proximal (closest) to the pelvic girdle. (2 pts)
Terms to use: tibia and fibula; tarsometatarsus; phalanges; astragalus and calcaneum; femur; ungual a.
b.
c.
d.
e.
f.
b)
Considering the bones that are present in these regions in the living animal, how complete is this specimen? (1 pt)
c)
Bones 21 and 22 of our organism represent the ankle bones. What type of ankle configuration does our organism have? (Appropriate terms could be “
crurotarsal
ankle”
like in the left figure or “
mesotarsal
ankle”
like in the right figure. The red line in each is the plane of the ankle hinge). (1 pt)
d)
What features are present in this portion of the skeleton that make you confident this fossil is a dinosaur? Consider the shared derived characters that are unique to Dinosauria and are not present in other groups. (1 pt)
e)
Examine the hip and the orientation of the pubis. What type of hip is present in this specimen? (1pt)
f)
How many functional digits are there on the foot? (1pt)
Femur
Tibia and Fibula
Phalanges
Tarsometatarsus
Ungual
Astragalus and Calacaneum
This is a mesotarsal ankle since the bone reflects the configuration shown in the right figure.
All the bones that make up the hindlimb and pelvis are present, therefore it could be infered that the specimen is complete. The regions presented are in fact complete
The shape of the phalanges, presence of claws, and the proof of the specimen being "lizard hipped" make me confident that the fossil is a dinosaur.
The pelvis is lizard-hipped so that would make the specimen part of the Saurischian orientation.
There are 4 functional digits on the foot presented.
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