Excavation Stage III - Lab 7 assignment F23.docx (2)

GEOL207: Dinosaur World Name: _________________________ Lab Section: 200 500 501 502 503 504 505 DINOSAUR EXCAVATION STAGE III Part I: Excavation Stage iII - Pelvic Girdle and Hindlimb 1) Find Your Bearings. a. Make a sketch of the bones within the sand box, and of the bones on the double table. An arrow is labeled in the top right corner of the sandbox, indicating the direction of North. Be sure to make a note of the orientation of the excavated bones with respect to North. Using the North arrow, at the end of the class – you can overlay all your site maps to get a sense of the entire skeleton in the ground (not required) b. On your site map indicate each bone that has been numerically labeled. 2) Identify and Catalog the Bones: use the Excel table (Table 2) at the end of this handout to catalog the bones recovered during the excavation. This will be your Bone Catalog. You will use this table to compile your notes for steps 2a-e. (5pts) a) For each bone that you numbered on the image, identify it (to the best of your ability) in the column labeled “Bone Identification.” b) Identify which region of the skeleton that these bones represent ( e.g., Hindlimb, Forelmb, Caudal, Cervical, Pelvis etc.). Record this is the column labeled “Skeletal Region.” c) You should take some measurements (length, width, etc .) of some of the bones You don’t have to do all of them, just the ones with an ‘*’! Record these in the column labeled “Measurements.” d) Carefully examine the taphonomic condition of each bone. Is it crushed, fragmented, or whole? Are the articulation sites preserved? Record these notes in the column labeled “Taphonomic Condition.” e) If you have any other notes or want to keep track of any other information, then you can include them in the column labeled “Other Notes.”

GEOL207: Dinosaur World Name: _________________________ Lab Section: 200 500 501 502 503 504 505 3) Interpret the Skeleton: Answer the following questions as they pertain to the excavated skeletal region a) One important dinosaurian synapomorphy is the perforate (pierced or open) acetabulum , simply a "hip bone" (actually three connected bones, together called the pelvis) with a hole in the center where the head of the femur ("thigh bone") fits. What are the three bones that comprise the pelvic girdle ( e.g., “hip bone”)? (3pts) i. ii. iii. iv. What do we call the opening between these three bones? (1pt) b) Dinosauria contains two major groups of dinosaurs: the Ornithischia, or "bird-hipped,” and the Saurischia, or "lizard-hipped," dinosaurs. The most prominent difference between the two types of hip is the orientation of the pubis. For each group, indicate whether the direction (anterior or posterior) the pubis generally projects from the pelvic girdle. (2pts) i. Ornithischian:____________________ ii. Saurischian:______________________ c) Use the image below or click the hyperlinks and observe the orientation of the pubis within the pelvic girdle on the following dinosaur skeletons and indicate if the dinosaur most closely resembles a general saurischian or an ornithischian pelvic girdle. (3pts) i. Spinosaurus ii. Stegosaurus iii. Brachiosaurus

GEOL207: Dinosaur World Name: _________________________ Lab Section: 200 500 501 502 503 504 505 f. f) Analyze the Tyrannosaurus Rex foot claw and the Velociraptor claw (ungual) . What could the size and shape of these claws indicate about each predator’s feeding habits? How does the footclaw of our organism compare? (2pts) g) Bone 21 and 22 of our organism represent the ankle bones. What type of ankle configuration does our organism have? (2pts) 4) Depositional Environment 1. Sedimentary structures are geologic features of the substrate that were preserved and provide evidence for the environment of deposition ( e.g., streams, deserts, etc). A few sedimentary structures discovered at the dig site are mud-cracks , ripple marks and smooth, rounded rocks . Use these to interpret and hypothesize the environment of deposition.

GEOL207: Dinosaur World Name: _________________________ Lab Section: 200 500 501 502 503 504 505 5) Stratigraphic Column I (Sediments Beneath the Dinosaur-Bearing Horizon) Sediments Below the Dinosaur-bearing Horizon: Silty mudstones and silty, fine-grained sandstones. Fossilized organisms in the sediments are fossilized oysters, such as Crassostrea sp. (C), Baculites grandis to the west of the dinosaur, and B. cuneatus to the east of the dinosaur. Baculites (A, B) is a type of ammonite. These organisms are usually preserved as fragments of the shell. A shows a reconstruction of a Baculites cephalopod. B shows Baculites fossils. C. shows a Cretaceous example of Crassostrea . You will need to use the information provided in the ‘Stratigraphic Column’ to answer the following questions. 1. What is the importance of the fossils found in the horizon below the dinosaur? 2. Describe this horizon. What type of environment does it represent (e.g. terrestrial, marine, etc.)? Be as specific as possible and provide evidence for your conclusion? 3. List the species names of the organisms found in this horizon and make a species range chart, using the information from their FADs and LADs (First Appearance Datum and Last Appearance Datum, respectively) to constrain the age of the excavation site. Hint: use the names of organisms to conduct a literature search for their geologic time ranges using Google Scholar and/or Wikipedia. Record that information in the chart below. Organism FAD Age (Ma) LAD Age (Ma) A. Baculites grandis (west) 70.45 69.55 B. Baculites cuneatus (east) _______________ _______________ C. Crassostrea sp. _______________ _______________ 4. Relatively, how old is the sediment beneath the dinosaur bearing horizon? Hint: What is the overlapping age range in which all three of the organisms coexisted?

GEOL207: Dinosaur World Name: _________________________ Lab Section: 200 500 501 502 503 504 505 Table 3. Bone catalog for Excavation Stage III. Bone Number Bone Identification Skeletal Region Measurements Taphonomic Condition 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