A new approach to determining the habitual neck posture of sauropods based on the behaviour of...

A new approach to determiningthe 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 91766-1854, USA.

Historical background

The earliest sauropod reconstructions had horizontal necks

Camarasaurus (Ryder 1877)Reprinted by Osborn and Mook (1921: plate LXXXII)

Historical background

The earliest sauropod reconstructions had horizontal necks

Brontosaurus (Marsh 1883: plate I)

Historical background

The earliest sauropod reconstructions had horizontal necks

Diplodocus carnegii (Hatcher 1901: plate VIII)

Historical background

Later sauropod reconstructions had raised necks

Camarasaurus (Osborn and Mook 1921: plate LXXXIV)

Historical background

Later sauropod reconstructions had raised necks

Brachiosaurus brancai (Janensch 1950b: plate VIII)

Historical background

Later sauropod reconstructions had raised necks

Brachiosaurus brancai(Paul 1988:fig. 1)

Historical background

Later sauropod reconstructions had raised necks

?!

Brachiosaurus brancai(Paul 1988:fig. 1)

Historical background

Later sauropod reconstructions had raised necksLater sauropod reconstructions had raised necks

Brontosaurus (Zallinger's 1947 mural at YPM)

Recent work has reverted to horizontal

Necks considered low and inflexibleNecks considered low and inflexible

Leicester City Museum Leicester City Museum Cetiosaurus oxoniensisCetiosaurus oxoniensis

Recent work

Necks considered low and inflexible

Martin (1987: fig. 2)

Recent work

Osteological neutral pose (ONP)

Stevens and Parrish (2005b: fig. 10.3A) – same specimen

Recent work

Osteological neutral pose (ONP)

Stevens and Parrish (2005a: fig. 6.5B) – Diplodocus carnegii

Recent work

(Giraffes are different: ONP gives rise to an erect neck)

Stevens and Parrish (2005a: fig. 6.2) – Giraffe

Recent work

Sauropod necks considered low and inflexible

Stevens and Parrish (2005a: fig. 6.14) – Diplodocus carnegii

Recent work

Necks considered low and inflexible

Stevens and Parrish (1999: fig. 2B) – Diplodocus carnegiiDinoMorph

Recent work

Necks considered low and inflexible

Stevens and Parrish (1999: 798, 800)

Recent work

Necks considered low and inflexible

Stevens and Parrish (1999: 798, 800)

Recent work

Necks considered low and inflexible

Stevens and Parrish (1999: 798, 800)

Recent work

Necks considered low and inflexible

Claim: ONP is sub-horizontal in all sauropods

Recent work

Necks considered low and inflexible

Claim: ONP is sub-horizontal in all sauropodsClaim: ONP is the habitual posture

Recent work

Neck held high

Christian and Dzemski (2007) – stress patterns

Recent work

Neck held high

Christian and Dzemski (2007) – stress patterns

Similar findings by ...

Recent work

Neck held high

Christian and Dzemski (2007) – stress patterns

Similar findings by ...Christian and Heinrich (1998)

Recent work

Neck held high

Christian and Dzemski (2007) – stress patterns

Similar findings by ...Christian and Heinrich (1998)

Christian (2002a)

Recent work

Neck held high

Christian and Dzemski (2007) – stress patterns

Similar findings by ...Christian and Heinrich (1998)

Christian (2002a)Christian (2002b)

Recent work

Neck held high

Christian and Dzemski (2007) – stress patterns

Similar findings by ...Christian and Heinrich (1998)

Christian (2002a)Christian (2002b)

Christian (2004)

Recent work

Neck held high

Christian and Dzemski (2007) – stress patterns

Similar findings by ...Christian and Heinrich (1998)

Christian (2002a)Christian (2002b)

Christian (2004)

One-man crusade?

One-man crusade?

The state of the art

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

But

ButWhat do extant animals do?

Habitual posture of extant animals

Vidal et al (1986) on “unrestrained awake animals”

Cat, sitting and standing (Vidal et al. 1986: fig. 3)

Habitual posture of extant animals

Vidal et al (1986) on “unrestrained awake animals”

But what about nice, cuddly bunny-rabbits?

Habitual posture of extant animals

Nice, cuddly bunny-rabbits have vertical necks, too.

Rabbit in semi-alert posture (Vidal et al. 1986: fig. 4)

Habitual posture of extant animals

And so do rats and guinea pigs

Rat and guinea pig (Vidal et al. 1986: fig. 5B-C)

Habitual posture of extant animals

And so do rats and guinea pigs

Rat and guinea pig (Vidal et al. 1986: fig. 5B-C)

Is it just mammals?

Is it just mammals?

Habitual posture of extant animals

What about the humble chicken?

Habitual posture of extant animals

Chicken necks habitually bend backwards!

(Vidal et al. 1986: fig. 7)

Habitual posture is not ONP

Vidal et al.'s (1986) key findings

Habitual posture is not ONP

Cervicodorsal joint is maximally extended

Vidal et al.'s (1986) key findings

Habitual posture is not ONP

Cervicodorsal joint is maximally extended

Craniocervical joint is maximally flexed

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

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

Vidal et al.'s (1986) key findings

Cold-blooded/sprawling amniotes

Alligator (Claessens, unpublished photo)

Cold-blooded/sprawling amniotes

Unspecified lizard (Vidal et al. 1986: fig. 8A)Varanid lizard (Brainerd and Owekowicz 2006: fig. 4)

Cold-blooded/sprawling amniotes

Turtle (Landberg et al. 2003:fig. 8)

Non-amniote tetrapods

Salamander (Simons et al. 2000:fig. 4)

Neck posturemapped ontocladogram

Neck posturemapped ontocladogram

Neck posturemapped ontocladogram

Upright posture

Neck posturemapped ontocladogram

Upright posture

Homeothermy

Diplodocus carnegii(based on Hatcher 1901)

(Skull orientation basedon occipital condyle)

Dicraeosaurus deathmatch!

Janensch (1936: plate 16) vs. Wilson (2002: fig. 1)

Dicraeosaurus deathmatch!

Janensch (1936: plate 16) vs. Wilson (2002: fig. 1)

Also ... what does “neutral” actually mean?

Modified from Stevens and Parrish (2005b: fig. 6.8)Neutral pose

Also ... what does “neutral” actually mean?

Modified from Stevens and Parrish (2005b: fig. 6.8)Ventrally deflected by 8°

Modified from Stevens and Parrish (2005b: fig. 6.8)Dorsally deflected by 8°

Also ... what does “neutral” actually mean?

Thanks for listening

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Your neck(all seven vertebrae)

Sauroposeidon C8 (one vertebra)