Excavation Stage III - Lab 7 assignment F23 UPDATED.docx

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.”

GEOL207: Dinosaur World Name:_______________________ Lab Section: 200 500 501 502 503 504 505 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 iii. Brachiosaurus Ornithischian Pelvic girdle d) Analyze the pelvic girdle of the basal theropod Sarcosaurus woodii . i. Which pelvic bones are present? Which bone is missing? (2pts) Missing just pubis. ii. Which direction (anterior or posterior) would the missing bone project from the pelvic girdle ( i.e ., is it a saurischian or an ornithischian)? (2pts) It would be projecting anterior which would reveal that the organism is saurischian. iii. Modern birds are “bird-hipped;” however, their ancestors (i.e. , the theropods) were “lizard-hipped.” How does the pelvic girdle of the Greylag Goose ( Anser anser) differ from that of a basal theropod, suc h as Sa rcosaurus woodii ? (2pts) The goose is more comparable to an Ornithischian then to a theropod that has a Saurischian skeleton like Sarcosaurus. iv. Does the hip bones of our mystery organism look more similar to the Sarcosaurus or the Greylag Goose? (2pts) Our mystery organism is more similar to the Sarcosaurus due to the similarities in the overall pelvic structure. e) Starting proximal (closest) to the pelvic girdle, order the bones of the hindlimb. (3pts)

GEOL207: Dinosaur World Name:_______________________ Lab Section: 200 500 501 502 503 504 505 tibia and fibula tarsometatarsus phalanges astragalus and calcaneum femur ungual a. femur b. tibia and fibula c. astragalus and calcaneum d. tarsometatarsus e. ungual f. phalanages 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) Velociraptor claws are used to subdue prey and have a slender/sleek build which will help sneak up on prey. T-Rex claws were used to stomp on prey to efficiently kill prey or for stability. Our footclaw is more similar to the T-Rex due to not having the claw. g) Bone 21 and 22 of our organism represent the ankle bones. What type of ankle configuration does our organism have? (2pts) Our organism has a theropod ankle configuration. 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. Given the evidence of mud-cracks, the organism most likely resided in a river-based environment. 5) Stratigraphic Column I (Sediments Beneath the Dinosaur-Bearing Horizon)

GEOL207: Dinosaur World Name:_______________________ Lab Section: 200 500 501 502 503 504 505 a. What is your initial hypothesis from stage I of the taxonomic identification of the skeletal remains? Do you still agree with these hypotheses? Explain. (2pts) Our hypothesis was that our organism is an herbivore, but we disagree with the hypothesis because our organism has claws which can suggest it was a carnivore. b. Did you unearth any new evidence from the excavation site to refine your identification? Be specific. (2pts) Claws and as well as the overall ankle structure. c. Are you able to definitively determine the type of dinosaur? If not, what other information do you need? Hint: Review the SDCs of dinosaurs from lecture. (2pts) Not yet, we need the skull in order to determine to see if it is a carnivorous dinosaur. d. Are there any groups you able to rule out as not being the taxonomic identification of the organism? (2pts) Most likely herbivore and Ornithsicans due to our organism having claws. e. What other information would you need to make a better and more informed taxonomic identification? (2pts) Skulls, possible additional damages to bones, and stomach content.

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* Femur Hindlimb 81.5 22 Whole 2* Tibia Hindlimb 84 20 Whole 3 Fibula Hindlimb Whole 4* Tarsal Hindlimb 51.5 20.5 Whole 5 Ungual Hindlimb Whole 6 Metatarsal Hindlimb Whole 7 Metatarsal Hindlimb Whole 8 Metatarsal Hindlimb Whole 9 Metatarsal Hindlimb Whole 10 Phalanges Hindlimb Whole 11 Metatarsal Hindlimb Whole 12 Metatarsal Hindlimb Whole 13 Metatarsal Hindlimb Whole 14 Phalanges Hindlimb Whole 15 Hindlimb Hindlimb Whole 16 Hindlimb Hindlimb Whole 17 Metatarsal Hindlimb Whole 18 Phalanges Hindlimb Whole 19 Illium Pelvis Fragmented 20 Ischium Pelvis Fragmented 21 Calcaneum Hindlimb Whole 22 Astragalus Hindlimb Whole