Slide 1

Why giraffes have short necks Michael P. Taylor University of Bristol dino@miketaylor.org.uk Mathew J. Wedel Western University of Health Sciences mathew.wedel@gmail.com Slide 2 Why giraffes have short necks and how sauropods got it right Michael P. Taylor University of Bristol dino@miketaylor.org.uk Mathew J. Wedel Western University of Health Sciences mathew.wedel@gmail.com Slide 3 Slide 4 Slide 5 Slide 6 Slide 7 Slide 8 Slide 9 Slide 10 Slide 11 Slide 12 Slide 13 Slide 14 Slide 15 Slide 16 Slide 17 Slide 18 Slide 19 Slide 20 Slide 21 Slide 22 Slide 23 Slide 24 3-meter barrier for all non-aquatic animals Slide 25 Long-necked sauropod groups Upchurch et al. (2004:fig. 13.18) Slide 26 Long-necked sauropod groups Upchurch et al. (2004:fig. 13.18) Slide 27 Long-necked sauropod groups I suck... Upchurch et al. (2004:fig. 13.18) Slide 28 Long-necked sauropod groups Magic I suck... Upchurch et al. (2004:fig. 13.18) Slide 29 Factors contributing to long necks 1. No constraint on vertebral count Paraceratherium (Osborn 1923:fig 1) Slide 30 Factors contributing to long necks 1. No constraint on vertebral count Mamenchisaurus (modified from Ouyang and Ye 2003:fig. 13) Paraceratherium (Osborn 1923:fig 1) Slide 31 Factors contributing to long necks 2. Heads that did not process food Slide 32 Factors contributing to long necks 2. Heads that did not process food Diplodocus Slide 33 Factors contributing to long necks 2. Heads that did not process food Unholy Diplodocus Elephas hybrid Slide 34 Factors contributing to long necks 3. Absolutely large bodies Slide 35 Factors contributing to long necks 3. Absolutely large bodies Slide 36 C Factors contributing to long necks 3. Absolutely large bodies Crap. Slide 37 C Factors contributing to long necks 3A. Large quadrupedal bodies Slide 38 Crap. C Factors contributing to long necks 3A. Large quadrupedal bodies Slide 39 C Factors contributing to long necks 3A. Large quadrupedal bodies Crap. Slide 40 Factors contributing to long necks 3. Absolutely large bodies Parrish (2006) showed that sauropod neck length scales with torso length to the power 1.35 Slide 41 Factors contributing to long necks 3. Absolutely large bodies Carpenter (2006) scaled Amphicoelias fragillimus as 2.2 times Diplodocus. But Parrish suggests neck is 2.2^1.35 = 2.9 times => a neck 22 m long Slide 42 Factors contributing to long necks 4. Air-sacs overcame dead-space Slide 43 Factors contributing to long necks 4. Air-sacs overcame dead-space Like ostriches? Slide 44 Factors contributing to long necks 4. Air-sacs overcame dead-space But what about sperm whales? Paul 1998:fig. 11 Slide 45 Factors contributing to long necks 4. Air-sacs overcame dead-space But what about sperm whales? Paul 1998:fig. 11 Slide 46 Factors contributing to long necks 5. Vertebral architecture Diplodocus carnegii holotype CM 84, cervical 10 (Hatcher 1901:plate III) Slide 47 Factors contributing to long necks 5. Vertebral architecture Diplodocus carnegii holotype CM 84, cervical 10 (Hatcher 1901:plate III) Neural spine Prezygapophysis Post- zygapophysis Cervical rib Centrum Slide 48 Cervical vertebral innovations 1. Extreme pneumaticity 2. Bifid neural spines 3. Elongate cervical ribs Slide 49 Cervical vertebral innovations 1. Extreme pneumaticity Ostrich Slide 50 Cervical vertebral innovations 1. Extreme pneumaticity Diplodocus Slide 51 Cervical vertebral innovations 1. Extreme pneumaticity Diplodocus modified from Paul 1998:fig. 1(a)F Slide 52 Cervical vertebral innovations 1. Extreme pneumaticity Diplodocus cervical cross-sections Paul 1997:fig. 4 Schwarz et al. 2007:fig. 7A2 Slide 53 Cervical vertebral innovations 1. Extreme pneumaticity Diplodocus Slide 54 Cervical vertebral innovations 1. Extreme pneumaticity Diplodocus Slide 55 Cervical vertebral innovations 1. Extreme pneumaticity Diplodocus Slide 56 Cervical vertebral innovations 1. Extreme pneumaticity Red tailed hawk Slide 57 Cervical vertebral innovations 2. Bifid neural spines Apatosaurus Slide 58 Long-necked sauropod groups Upchurch et al. (2004:fig. 13.18) Slide 59 Long-necked sauropod groups Bifid neural spines evolved at least five times Never secondarily lost? Otherwise found only in the rhea (and only just) Upchurch et al. (2004:fig. 13.18) Slide 60 Cervical vertebral innovations 2. Bifid neural spines Alexander (1985) thought the trough was filled with a giant elastin ligament Diplodocus Slide 61 Cervical vertebral innovations 2. Bifid neural spines Apatosaurus Slide 62 Cervical vertebral innovations 2. Bifid neural spines Apatosaurus Slide 63 Cervical vertebral innovations 2. Bifid neural spines Apatosaurus Slide 64 Cervical vertebral innovations 2. Bifid neural spines Diplodocus (Schwarz et al. 2007:fig. 7A2) Slide 65 Cervical vertebral innovations 2. Bifid neural spines Slide 66 Cervical vertebral innovations 2. Bifid neural spines Slide 67 Cervical vertebral innovations 2. Bifid neural spines Slide 68 Cervical vertebral innovations 3. Elongate cervical ribs Turkey cervical 7 Slide 69 Cervical vertebral innovations 3. Elongate cervical ribs Turkey cervical 7 Slide 70 Cervical vertebral innovations 3. Elongate cervical ribs 4.1 m Turkey cervical 7 Mamenchisaurus Slide 71 Cervical vertebral innovations 3. Elongate cervical ribs 4.1 m Mamenchisaurus That lame giraffe Turkey cervical 7 Slide 72 Cervical vertebral innovations 3. Elongate cervical ribs Giraffatitan Slide 73 Cervical vertebral innovations 3. Elongate cervical ribs Giraffatitan Slide 74 Cervical vertebral innovations 3. Elongate cervical ribs Giraffatitan Slide 75 Comparison with birds and crocs Turkey cervical 7 Slide 76 Comparison with birds and crocs Turkey cervical 7 Slide 77 Comparison with birds and crocs Turkey cervical 7 Epipophysis Slide 78 Comparison with birds and crocs Turkey cervical 7 Slide 79 Comparison with birds and crocs AlligatorMajungasaurusTurkey Majungasaurus from O'Connor 2007:figs. 8, 20 Slide 80 Comparison with birds and crocs AlligatorMajungasaurusTurkey Majungasaurus from O'Connor 2007:figs. 8, 20 Slide 81 Comparison with birds and crocs AlligatorMajungasaurusTurkey Majungasaurus from O'Connor 2007:figs. 8, 20 Slide 82 Comparison with birds and crocs AlligatorMajungasaurusTurkeyGiraffatitan Giraffatitan from Janensch 1950:fig. 46 Majungasaurus from O'Connor 2007:figs. 8, 20 Slide 83 Comparison with birds and crocs AlligatorMajungasaurusTurkeyGiraffatitanCamarasaurus Giraffatitan from Janensch 1950:fig. 46 Camarasaurus from Osborn and Mook 1921:plate LXVII Majungasaurus from O'Connor 2007:figs. 8, 20 Slide 84 Comparison with birds and crocs Analogous but not homologous AlligatorMajungasaurusTurkeyGiraffatitanCamarasaurus Giraffatitan from Janensch 1950:fig. 46 Camarasaurus from Osborn and Mook 1921:plate LXVII Majungasaurus from O'Connor 2007:figs. 8, 20 Slide 85 Why are epipophyses not elongate? Euhelopus (Wiman 1929:plate III) Slide 86 Why are epipophyses not elongate? Euhelopus (Wiman 1929:plate III) Slide 87 Why are epipophyses not elongate? Euhelopus (Wiman 1929:plate III) Slide 88 Why are epipophyses not elongate? Euhelopus (Wiman 1929:plate III) Slide 89 Why are epipophyses not elongate? Deinonychus (Ostrom 1969:fig. 37) Slide 90 Why are epipophyses not elongate? Giraffatitan (Janensch 1950:fig. 43) Slide 91 Why are epipophyses not elongate? Need finer control for precise movements requires shorter levers Giraffatitan (Janensch 1950:fig. 43) Slide 92 Why are epipophyses not elongate? Tendon is stronger in tension than bone Giraffatitan (Janensch 1950:fig. 43) Slide 93 Why are epipophyses not elongate? Muscles expand when they contract lengthways Giraffatitan (Janensch 1950:fig. 43) Slide 94 Why are epipophyses not elongate? Muscles expand when they contract lengthways Giraffatitan (Janensch 1950:fig. 43) Slide 95 Why are epipophyses not elongate? Slide 96 Crap. Slide 97 Conclusion TaxonMany vertebrae Small head (no dental battery) Large body, four legs Air-sacsPneumatic vertebrae Elongate cervical ribs Giraffe Giant rhinos Ostrich Theropods Pterosaurs Sauropods Slide 98 Conclusion TaxonMany vertebrae Small head (no dental battery) Large body, four legs Air-sacsPneumatic vertebrae Elongate cervical ribs Giraffe X XXXXX Giant rhinos Ostrich Theropods Pterosaurs Sauropods Slide 99 Acknowledgements Everyone who allowed us access to specimens Everyone that we stole images from Western University for sending Matt to the UK Sauroposeidon Slide 100 Further reading Sauropod Vertebra Picture of the Week: http://svpow.com/ Taylor and Wedel 2013a: https://peerj.com/articles/36https://peerj.com/articles/36 Email: dino@miketaylor.org.uk Sauroposeidon