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A new approach to determining the habitual neck posture of sauropods

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1 A new approach to determining the habitual neck posture of sauropods
based on the behaviour of extant animals Michael P. Taylor1 Mathew J. Wedel2 Darren Naish1 1Palaeobiology Research Group, School of Earth and Environmental Sciences, University of Portsmouth, Burnaby Building, Burnaby Road, Portsmouth PO1 3QL, UK 2Department of Anatomy and College of Podiatric Medicine, Western University of Health Sciences, 309 E. Second Street, Pomona, California , USA.

2 Historical background
The earliest sauropod reconstructions had horizontal necks Camarasaurus (Ryder 1877)‏ Reprinted by Osborn and Mook (1921: plate LXXXII)‏

3 Historical background
The earliest sauropod reconstructions had horizontal necks Brontosaurus (Marsh 1883: plate I)‏

4 Historical background
The earliest sauropod reconstructions had horizontal necks Diplodocus carnegii (Hatcher 1901: plate VIII)‏

5 Historical background
Later sauropod reconstructions had raised necks Camarasaurus (Osborn and Mook 1921: plate LXXXIV)‏

6 Historical background
Later sauropod reconstructions had raised necks Brachiosaurus brancai (Janensch 1950b: plate VIII)‏

7 Historical background
Later sauropod reconstructions had raised necks Brachiosaurus brancai (Paul 1988:fig. 1)‏

8 Historical background
Later sauropod reconstructions had raised necks ?! Brachiosaurus brancai (Paul 1988:fig. 1)‏

9 Historical background
Later sauropod reconstructions had raised necks Brontosaurus (Zallinger's 1947 mural at YPM)‏

10 Recent work has reverted to horizontal
Necks considered low and inflexible Leicester City Museum Cetiosaurus oxoniensis

11 Necks considered low and inflexible
Recent work Necks considered low and inflexible Martin (1987: fig. 2)‏

12 Recent work Osteological neutral pose (ONP)‏
Stevens and Parrish (2005b: fig. 10.3A) – same specimen

13 Recent work Osteological neutral pose (ONP)‏
Stevens and Parrish (2005a: fig. 6.5B) – Diplodocus carnegii

14 Recent work (Giraffes are different: ONP gives rise to an erect neck)‏
Stevens and Parrish (2005a: fig. 6.2) – Giraffe

15 Recent work Sauropod necks considered low and inflexible
Stevens and Parrish (2005a: fig. 6.14) – Diplodocus carnegii

16 Recent work Necks considered low and inflexible
Stevens and Parrish (1999: fig. 2B) – Diplodocus carnegii DinoMorph

17 Recent work Necks considered low and inflexible
Stevens and Parrish (1999: 798, 800)‏

18 Recent work Necks considered low and inflexible
Stevens and Parrish (1999: 798, 800)‏

19 Recent work Necks considered low and inflexible
Stevens and Parrish (1999: 798, 800)‏

20 Recent work Necks considered low and inflexible
Claim: ONP is sub-horizontal in all sauropods

21 Recent work Necks considered low and inflexible
Claim: ONP is sub-horizontal in all sauropods Claim: ONP is the habitual posture

22 Christian and Dzemski (2007) – stress patterns
Recent work Neck held high Christian and Dzemski (2007) – stress patterns

23 Christian and Dzemski (2007) – stress patterns
Recent work Neck held high Similar findings by ... Christian and Dzemski (2007) – stress patterns

24 Christian and Dzemski (2007) – stress patterns
Recent work Neck held high Similar findings by ... Christian and Heinrich (1998)‏ Christian and Dzemski (2007) – stress patterns

25 Christian and Dzemski (2007) – stress patterns
Recent work Neck held high Similar findings by ... Christian and Heinrich (1998)‏ Christian (2002a)‏ Christian and Dzemski (2007) – stress patterns

26 Christian and Dzemski (2007) – stress patterns
Recent work Neck held high Similar findings by ... Christian and Heinrich (1998)‏ Christian (2002a)‏ Christian (2002b)‏ Christian and Dzemski (2007) – stress patterns

27 Christian and Dzemski (2007) – stress patterns
Recent work Neck held high Similar findings by ... Christian and Heinrich (1998)‏ Christian (2002a)‏ Christian (2002b)‏ Christian (2004)‏ Christian and Dzemski (2007) – stress patterns

28 Christian and Dzemski (2007) – stress patterns
Recent work Neck held high Similar findings by ... Christian and Heinrich (1998)‏ Christian (2002a)‏ Christian (2002b)‏ Christian (2004)‏ One-man crusade? One-man crusade? Christian and Dzemski (2007) – stress patterns

29 Low necks popularised by the BBC (and AMNH)‏
The state of the art Low necks popularised by the BBC (and AMNH)‏

30 Low necks popularised by the BBC (and AMNH)‏
The state of the art Low necks popularised by the BBC (and AMNH)‏ All based on ONP All based on ONP

31 But

32 But What do extant animals do?

33 Habitual posture of extant animals
Vidal et al (1986) on “unrestrained awake animals” Cat, sitting and standing (Vidal et al. 1986: fig. 3)‏

34 Habitual posture of extant animals
Vidal et al (1986) on “unrestrained awake animals” But what about nice, cuddly bunny-rabbits?

35 Habitual posture of extant animals
Nice, cuddly bunny-rabbits have vertical necks, too. Rabbit in semi-alert posture (Vidal et al. 1986: fig. 4)‏

36 Habitual posture of extant animals
And so do rats and guinea pigs Rat and guinea pig (Vidal et al. 1986: fig. 5B-C)‏

37 Habitual posture of extant animals
And so do rats and guinea pigs Is it just mammals? Is it just mammals? Rat and guinea pig (Vidal et al. 1986: fig. 5B-C)‏

38 Habitual posture of extant animals
What about the humble chicken?

39 Habitual posture of extant animals
Chicken necks habitually bend backwards! (Vidal et al. 1986: fig. 7)‏

40 Vidal et al.'s (1986) key findings Habitual posture is not ONP

41 Vidal et al.'s (1986) key findings
Habitual posture is not ONP Cervicodorsal joint is maximally extended

42 Vidal et al.'s (1986) key findings
Habitual posture is not ONP Cervicodorsal joint is maximally extended Craniocervical joint is maximally flexed

43 Vidal et al.'s (1986) key findings
Habitual posture is not ONP Cervicodorsal joint is maximally extended Craniocervical joint is maximally flexed Median part of neck is mostly held rigid

44 Vidal et al.'s (1986) key findings
Habitual posture is not ONP Cervicodorsal joint is maximally extended Craniocervical joint is maximally flexed Median part of neck is mostly held rigid The neck is raised and lowered at end joints

45 Cold-blooded/sprawling amniotes
Alligator (Claessens, unpublished photo)‏

46 Cold-blooded/sprawling amniotes
Unspecified lizard (Vidal et al. 1986: fig. 8A)‏ Varanid lizard (Brainerd and Owekowicz 2006: fig. 4)‏

47 Cold-blooded/sprawling amniotes
Turtle (Landberg et al. 2003:fig. 8)‏

48 Non-amniote tetrapods
Salamander (Simons et al. 2000:fig. 4)‏

49 Neck posture mapped onto cladogram

50 Neck posture mapped onto cladogram

51 Neck posture mapped onto cladogram Upright posture

52 Neck posture mapped onto cladogram Upright posture Homeothermy

53 Diplodocus carnegii (based on Hatcher 1901)‏ (Skull orientation based
on occipital condyle)‏

54 Dicraeosaurus deathmatch!
Janensch (1936: plate 16) vs. Wilson (2002: fig. 1)‏

55 Dicraeosaurus deathmatch!
Janensch (1936: plate 16) vs. Wilson (2002: fig. 1)‏

56 Also ... what does “neutral” actually mean?
Modified from Stevens and Parrish (2005b: fig. 6.8)‏ Neutral pose

57 Also ... what does “neutral” actually mean?
Modified from Stevens and Parrish (2005b: fig. 6.8)‏ Ventrally deflected by 8°

58 Also ... what does “neutral” actually mean?
Modified from Stevens and Parrish (2005b: fig. 6.8)‏ Dorsally deflected by 8°

59 Visit our blog: Sauropod Vertebra Picture of the Week
Thanks for listening Your neck (all seven vertebrae)‏ Sauroposeidon C8 (one vertebra)‏ Visit our blog: Sauropod Vertebra Picture of the Week


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