why giraffes have short necks …
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Why giraffes have short necks …. Michael P. Taylor University of Bristol [email protected] Mathew J. Wedel Western University of Health Sciences [email protected]. Why giraffes have short necks …. … and how sauropods got it right. Michael P. Taylor University of Bristol - PowerPoint PPT PresentationTRANSCRIPT
Why giraffes haveshort necks …
Michael P. TaylorUniversity of [email protected]
Mathew J. WedelWestern University ofHealth [email protected]
Why giraffes haveshort necks …
… and howsauropodsgot it right
Michael P. TaylorUniversity of [email protected]
Mathew J. WedelWestern University ofHealth [email protected]
3-meter barrier for all non-aquatic animals
Long-necked sauropod groupsUpchurch et al. (2004:fig. 13.18)
Long-necked sauropod groupsUpchurch et al. (2004:fig. 13.18)
Long-necked sauropod groups
I suck ...
Upchurch et al. (2004:fig. 13.18)
Long-necked sauropod groups
Magic
I suck ...
Upchurch et al. (2004:fig. 13.18)
Factors contributing to long necks1. No constraint on vertebral count
Paraceratherium (Osborn 1923:fig 1)
Factors contributing to long necks1. No constraint on vertebral count
Mamenchisaurus (modified from Ouyang and Ye 2003:fig. 13)
Paraceratherium (Osborn 1923:fig 1)
Factors contributing to long necks2. Heads that did not process food
Factors contributing to long necks2. Heads that did not process food
Diplodocus
Factors contributing to long necks2. Heads that did not process food
Unholy Diplodocus ☓ Elephas hybrid
Factors contributing to long necks3. Absolutely large bodies
Factors contributing to long necks3. Absolutely large bodies
C
Factors contributing to long necks3. Absolutely large bodies
Crap.
Crap.C
Factors contributing to long necks3A. Large quadrupedal bodies
Crap.C
Factors contributing to long necks3A. Large quadrupedal bodies
C
Factors contributing to long necks3A. Large quadrupedal bodies
Crap.
Factors contributing to long necks3. Absolutely large bodies
Parrish (2006) showed that sauropod neck lengthscales with torso length to the power 1.35
Factors contributing to long necks3. 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
Factors contributing to long necks4. Air-sacs overcame dead-space
Factors contributing to long necks4. Air-sacs overcame dead-space
Like ostriches?
Factors contributing to long necks4. Air-sacs overcame dead-space
But what aboutsperm whales?
Paul 1998:fig. 11
Factors contributing to long necks4. Air-sacs overcame dead-space
But what aboutsperm whales?
Paul 1998:fig. 11
Factors contributing to long necks5. Vertebral architecture
Diplodocus carnegii holotype CM 84, cervical 10 (Hatcher 1901:plate III)
Factors contributing to long necks5. Vertebral architecture
Diplodocus carnegii holotype CM 84, cervical 10 (Hatcher 1901:plate III)
Neural spine
PrezygapophysisPost-zygapophysis
Cervical rib
Centrum
Cervical vertebral innovations
1. Extreme pneumaticity2. Bifid neural spines3. Elongate cervical ribs
Cervical vertebral innovations1. Extreme pneumaticity
Ostrich
Cervical vertebral innovations1. Extreme pneumaticity
Diplodocus
Cervical vertebral innovations1. Extreme pneumaticity
Diplodocus modified from Paul 1998:fig. 1(a)F
Cervical vertebral innovations1. Extreme pneumaticity
Diplodocus cervical cross-sections
Paul 1997:fig. 4 Schwarz et al. 2007:fig. 7A2
Cervical vertebral innovations1. Extreme pneumaticity
Diplodocus
Cervical vertebral innovations1. Extreme pneumaticity
Diplodocus
Cervical vertebral innovations1. Extreme pneumaticity
Diplodocus
Cervical vertebral innovations1. Extreme pneumaticity
Redtailedhawk
Cervical vertebral innovations2. Bifid neural spines
Apatosaurus
Long-necked sauropod groupsUpchurch et al. (2004:fig. 13.18)
Long-necked sauropod groupsBifid neural spines evolvedat least five times
Never secondarily lost?
Otherwise found only inthe rhea (and only just)
Upchurch et al. (2004:fig. 13.18)
Cervical vertebral innovations2. Bifid neural spines
Alexander (1985) thoughtthe trough was filled witha giant elastin ligament
Diplodocus
Cervical vertebral innovations2. Bifid neural spines
Apatosaurus
Cervical vertebral innovations2. Bifid neural spines
Apatosaurus
Cervical vertebral innovations2. Bifid neural spines
Apatosaurus
Cervical vertebral innovations2. Bifid neural spines
Diplodocus (Schwarz et al. 2007:fig. 7A2)
Cervical vertebral innovations2. Bifid neural spines
Cervical vertebral innovations2. Bifid neural spines
Cervical vertebral innovations2. Bifid neural spines
Cervical vertebral innovations3. Elongate cervical ribs
Turkeycervical 7
Cervical vertebral innovations3. Elongate cervical ribs
Turkeycervical 7
Cervical vertebral innovations3. Elongate cervical ribs
4.1 m
Turkeycervical 7 Mamenchisaurus
Cervical vertebral innovations3. Elongate cervical ribs
4.1 m
Mamenchisaurus
That lamegiraffe
Turkeycervical 7
Cervical vertebral innovations3. Elongate cervical ribs
Giraffatitan
Cervical vertebral innovations3. Elongate cervical ribs
Giraffatitan
Cervical vertebral innovations3. Elongate cervical ribs
Giraffatitan
Comparison with birds and crocs
Turkey cervical 7
Comparison with birds and crocs
Turkey cervical 7
Comparison with birds and crocs
Turkey cervical 7
Epipophysis
Comparison with birds and crocs
Turkey cervical 7
Comparison with birds and crocsAlligator Majungasaurus Turkey
Majungasaurus from O'Connor 2007:figs. 8, 20
Comparison with birds and crocsAlligator Majungasaurus Turkey
Majungasaurus from O'Connor 2007:figs. 8, 20
Comparison with birds and crocsAlligator Majungasaurus Turkey
Majungasaurus from O'Connor 2007:figs. 8, 20
Comparison with birds and crocsAlligator Majungasaurus TurkeyGiraffatitan
Giraffatitan from Janensch 1950:fig. 46
Majungasaurus from O'Connor 2007:figs. 8, 20
Comparison with birds and crocsAlligator Majungasaurus TurkeyGiraffatitan Camarasaurus
Giraffatitan from Janensch 1950:fig. 46Camarasaurus from Osborn and Mook 1921:plate LXVIIMajungasaurus from O'Connor 2007:figs. 8, 20
Comparison with birds and crocs
Analogous but not homologous
Alligator Majungasaurus TurkeyGiraffatitan Camarasaurus
Giraffatitan from Janensch 1950:fig. 46Camarasaurus from Osborn and Mook 1921:plate LXVIIMajungasaurus from O'Connor 2007:figs. 8, 20
Why are epipophyses not elongate?
Euhelopus (Wiman 1929:plate III)
Why are epipophyses not elongate?
Euhelopus (Wiman 1929:plate III)
Why are epipophyses not elongate?
Euhelopus (Wiman 1929:plate III)
Why are epipophyses not elongate?
Euhelopus (Wiman 1929:plate III)
Why are epipophyses not elongate?
Deinonychus (Ostrom 1969:fig. 37)
Why are epipophyses not elongate?
Giraffatitan (Janensch 1950:fig. 43)
Why are epipophyses not elongate?
Need finer control for precise movements – requires shorter levers
Giraffatitan (Janensch 1950:fig. 43)
Why are epipophyses not elongate?
Tendon is stronger in tension than bone
Giraffatitan (Janensch 1950:fig. 43)
Why are epipophyses not elongate?
Muscles expand when they contract lengthways
Giraffatitan (Janensch 1950:fig. 43)
Why are epipophyses not elongate?
Muscles expand when they contract lengthways
Giraffatitan (Janensch 1950:fig. 43)
Why are epipophyses not elongate?
Why are epipophyses not elongate?
Crap.
Conclusion
Taxon Manyvertebrae
Small head(no dentalbattery)
Large body,four legs
Air-sacs Pneumaticvertebrae
Elongatecervical ribs
Giraffe
Giantrhinos ✓Ostrich
✓ ✓ ✓ ✓Theropods
✓ ✓ ✓Pterosaurs
✓ ✓Sauropods
✓ ✓ ✓ ✓ ✓ ✓
Conclusion
Taxon Manyvertebrae
Small head(no dentalbattery)
Large body,four legs
Air-sacs Pneumaticvertebrae
Elongatecervical ribs
Giraffe X X X X X XGiantrhinos ✓Ostrich ✓ ✓ ✓ ✓Theropods ✓ ✓ ✓Pterosaurs ✓ ✓Sauropods ✓ ✓ ✓ ✓ ✓ ✓
Acknowledgements
Everyone who allowed us access to specimensEveryone that we stole images fromWestern University for sending Matt to the UK
Sauroposeidon
Further readingSauropod Vertebra Picture of the Week: http://svpow.com/
Taylor and Wedel 2013a: https://peerj.com/articles/36
Email: [email protected]
Sauroposeidon