THE UNIVERSITY OF CALGARY Eric Snively A ... - Ohio University

More documents

Recommendations

Info

$Introduction to Numerical Math and Matlab ... - Ohio University$

tyrannosaurids, ornithomimid, and troodontid presumably relied upon ligaments to prevent the distal, triangular portion of the third metatarsal from being dislodged anteriorly during acutely angled footfalls. Distal ligaments, or proximal "snap" ligaments that mediated rotation (Wilson and Currie 1985), may have served this purpose in Tmodon or the ornithomimid. In contrast, the hook shaped proximal articulations in tyrannosaurids would have constrained movement, preventing posterior rotation of the proximal part of the third metatarsal. A strong role for distal ligaments in the tyrannosaurid metatarsus appears to be a reasonable possibiiity. From this comparative analysis of arctometatarsus morphologies, I derive a tentative hypothesis of tyrannosaurid pedal function. Specifically, the evidence suggests that the tyrannosaurid arctometatarsus was free to move distaliy about a proximal pivot point, and that proximal and distal ligaments constrained and facilitated such movement. The validity of this hypothesis rests upon more detailed examination of the tyrannosaurid arctometatarsus, which is the goal of Chapters 3 and 4 below. CONCLUDING COMMENTS As noted above, the relatively srnaIl sample size precludes statistically definitive segregation of MT III morphologies based on the PCA plots alone. However, the PCA results are cleafly interpretable in light of the observed proximal robustness of the specirnens. The following conclusions may be drawn from statistical and qualitative analysis of theropod third metatarsals:
a) There is no substitute for morphological description. Principal Components Analysis can reveal variance and covariance of an arbitrarily large number of measurements. However, subtle or retrospectively obvious details of morphology may be missed when one is initially choosing landmarks. Accounting for al1 informative landmarks is time wnsuming in terms of experimental design and measurement, while qualitative inspection of a specimen often quickly reveals morphological novelty. Examples in this study indude the shape of the mesotarsal articular surface of MT III in Plateosaurus, and the distal MT II articulation of the third metatarsal of Deinonychus. b) PCA can uncover not only patterns of morphological dustering, but also the importance of qualitatively unremarkabfe specimens. Carnosaurian and tyrannosaurid third metatarsals aggregate strongly in this study, and Troodon and the putatively herbivorous f ms are outliers at opposite ends of the robustness scale. CIear patterns do not emerge among smaller non- arctometatarsaiian coelurosaurs in third metatarsal morphology. The MT Ill of Elaphrosaums approximates the average morphology in ternis of size and shape. c) Proximal constriction distinguishes the arctometatarsalian MT III from other morphoIogies, but this element is variable in taxa that possess it. Third metatarsals traditionally recognized as arctometatarsalian occur above 0.22 along PC2, which is an index of proximal gracility (Figure 2.1 5). No non-derived morphologies duster wÏth them. Specimens of tyrannosaurids and the ornithomirnid have very simifar vaIues for PC2. Troodon displays an extremity of
Page 1 and 2:
THE UNIVERSITY OF CALGARY Functiona
Page 3:
Many figures in this thesis use col
Page 6 and 7:
ACKNOWLEûGEM ENTS Many friends and
Page 8 and 9:
Approval page Acknowledgements Tabi
Page 10 and 11:
CONCLUDING COMMENTS Figures for Cha
Page 12 and 13:
CHAPTER 5: Mechanical and phylogene
Page 14 and 15:
LIST OF FIGURES Figure 1 .l. Phylog
Page 16 and 17:
Figure 3.6. Osteological correlates
Page 18 and 19:
AMNH GI HMN IVPP MOR NMC OMNH PIN P
Page 20 and 21:
and constructional morphology revea
Page 22 and 23:
1985, Bryant and Seymour 1990). If
Page 24 and 25:
surfaces of a Tyrannosaurus rex spe
Page 26 and 27:
3. Troodontidae (Figure 1.2): Trwdo
Page 29 and 30:
Hypothesized functions of the tyran
Page 31 and 32:
1. Atomization (Chapters 2 and 3).
Page 33 and 34:
Figure 1.1. P hylogenetic diagram o
Page 35 and 36:
Figure 1.2. Phylogenetic diagram of
Page 37 and 38:
Figure 1.3. Phylogenetic diagram of
Page 39 and 40: Figure 1.4. Phylogenetic diagram of
Page 41: Figure 1 .S. Skeletal restorations
Page 44 and 45: did not quantify the degree of prox
Page 46 and 47: qualitative debate over arctometata
Page 48 and 49: This hypothesis focuses on tyrannos
Page 50 and 51: Table 2.1. Theropod and Plafeosauru
Page 52 and 53: specimens in the figures reflects a
Page 54 and 55: were not attempted. While this limi
Page 56 and 57: Chapter 3). 1 now address variation
Page 58 and 59: - Ç6'P 1 68'€tr 1 L'OC 99'66 L'9
Page 60 and 61: Table 2.3: Log-transformed values f
Page 62 and 63: experiences a sharp laterally indin
Page 64 and 65: ecause it can be cursorily dassifie
Page 66 and 67: arctometatarsalian specimens, the l
Page 68 and 69: ) Shaf€ and region of proximal ar
Page 70 and 71: a) Ginglymus. Figure 2.14 shows the
Page 72 and 73: ) Shaft and region of proximal arti
Page 74 and 75: measurements of width pV2S%TU-DE an
Page 76 and 77: Table 2.4b Variancelmeasurement eac
Page 78 and 79: the largest sum of linear measureme
Page 80 and 81: Table 2.5: Specimen statistics Herr
Page 82 and 83: and Sinraptor dongi specimens. With
Page 84 and 85: In addition, a hook like proximal a
Page 86 and 87: oth physical narrowing and elongati
Page 88 and 89: 1s the MT 111 shape segregation fun
Page 92 and 93: proximal constriction, white EImisa
Page 95: Figure 2.2. Tyrannosaurid, trwdonti
Page 99: Figure 2.4. Dromaeosaurid and carno
Page 102 and 103: - Anterior (flexor) surface medial
Page 105 and 106: Figure 2.7. Left MT III of Tyrannos
Page 107 and 108: Figure 2.8. Left MT III of Gorgosau
Page 109 and 110: Figure 2.9. Left MT III of an omith
Page 111 and 112: Figure 2.10. Left metatarsus of Tmd
Page 113 and 114: Figure 2.1 1. Left MT III of Elmisa
Page 115 and 116: Figure 2.12. Right MT III of Deinon
Page 117 and 118: Figure 2.13. Left MT III of Allosau
Page 119 and 120: Figure 2.14. Left metatarsus of Sin
Page 121 and 122: Figure 2.15. Plots of MT Ill specir
Page 123: Figure 2.16. Plot of third metatars
Page 126 and 127: tv . ... . Ri. . . .
Page 129 and 130: Figure 2.19. Plot of third metatars
Page 131 and 132: CHAPTER 3: Tensile keystone model o
Page 133 and 134: dynamically transmitted Iommotor fo
Page 135 and 136: Table 3.1 . Metatarsi examined in t
Page 137 and 138: interrnetatarsal dynamics in these
Page 139 and 140: compelled analysis of movement evid
Page 141 and 142:
Once prepared, TMP 94.1 2.602 and i
Page 143 and 144:
Daspletosaurus tomsus (MOR 590), an
Page 145 and 146:
2. Freedom of movement inferred fro
Page 147 and 148:
Table 3.2. Surface areas of intemet
Page 149 and 150:
phylogenetic bracketing Wtmer 1995)
Page 151 and 152:
4) Forces from anterior displacerne
Page 153 and 154:
e expected for tyrannosaurid interm
Page 155 and 156:
The preceding discussion derives fr
Page 157 and 158:
weapons sparring), and the arctomet
Page 159:
Figure 3.1. Schematic representatio
Page 163:
Figure 3.3. CT reconstruction of ri
Page 167:
Figure 3.5. MT II (left element) an
Page 171:
Page 175:
Page 179:
Figure 3.1 1 ae. The metatarsal rec
Page 187:
Figure 3.13. Ligament contribution
Page 191 and 192:
Figure 3.15. Anatorny of the equid
Page 193:
Figure 3.16. Cornparison of loading
Page 196 and 197:
(nodes), and solving stresslstrain
Page 198 and 199:
The practicality of the finite elem
Page 200 and 201:
collective density of trabeculae (K
Page 202 and 203:
A FORCE INPUTS AND MATERIAL PROPERT
Page 204 and 205:
Alexander et al. (1 979) rewrded a
Page 206 and 207:
The preceding loading regime entait
Page 208 and 209:
detemined by using the photographic
Page 210 and 211:
2. Preparation of data for contour
Page 212 and 213:
. - Elastic modulus (GP4 Ex EY Ez P
Page 214 and 215:
conversion. Volume-to-nuages facili
Page 216 and 217:
maintained. An angle of 2 degrees p
Page 218 and 219:
of MT III (Figure 4.4, pinpointed b
Page 220 and 221:
anterodorsal rotation of the distal
Page 222 and 223:
allowed to stretch slightly under t
Page 224:
Figure 4.1. Initial loads and bound
Page 228:
Figure 4.3. Finite element mesh of
Page 232:
Figure 4.5. Strain distribution in
Page 236 and 237:
CHAPTER 5: Mechanical and evolution
Page 238 and 239:
y distal intermetatarsal ligaments,
Page 240 and 241:
Probable fundion of the tyrannosaur
Page 242 and 243:
Ornitholestes, and camosaurs) incre
Page 244 and 245:
morphology matches in degree the co
Page 246 and 247:
discussion elucidates the evolution
Page 248 and 249:
face of the skull met part of the m
Page 250 and 251:
Alternately, a morphological novelt
Page 252 and 253:
outgroup to ail theropods, and the
Page 254 and 255:
convincingly evident in figures of
Page 256 and 257:
parsimonious scenarios are outlined
Page 258 and 259:
dromaeosaurids], and a dade compris
Page 260 and 261:
arctometatarsalian forrns. The conv
Page 262 and 263:
Proximal intermetatarsal ligaments
Page 264 and 265:
witti a surfeit of potentially supp
Page 267:
Figure 5.2. Phylogeny of the Therop
Page 271:
Page 275:
Page 278 and 279:
Bock W.J. and von Wahlert G. Evolut
Page 280 and 281:
Cume P.J. 1997. Theropoda. In: Fari
Page 282 and 283:
Grenard S. 1991. Handbook of Alliga
Page 284 and 285:
Liem K.F. and Osse J.W.M. 1975. Bio
Page 286 and 287:
Richtsmeier J.T. and Cheverud J.M.
Page 288 and 289:
Woo S., Maynard J., Butler O. 1987.
Page 290 and 291:
Different variables in a PCA will h
show all

THE UNIVERSITY OF CALGARY Eric Snively A ... - Ohio University

Create successful ePaper yourself

Delete template?

Save as template?