Re: [dinosaur] Ostrich decomposition and opisthotonus with implications for theropod dinosaurs (free pdf)

[Tim Williams <tijawi@gmail.com>]

I dutifully read this paper (well, skimmed it) even though
Lingham-Soliar's previous studies have left me cold.  Sure enough,
this study includes a glaring red herring, in which it is avered that
_Sinosauropteryx_ did not have protofeathers, based on comparison with
a rotting ostrich chick:

"In _Sinosauropteryx_ IVPP V12415 there is a unique record
showing the opisthotonic process (sharp retraction of neck and
protraction of the tail) occurring in three stages in the tail, evi-
dent by a trail of associated material, for example, scales and
bone (Lingham-Soliar, 2015). Retaining immaculately aligned
‘protofeathers’ while the tail was dragged post-mortem along
the matrix holds little credulity. The tangled mass of feathers
along the periphery of the decomposing ostrich chicks adds
support against the neat orientation required by the protofeather
notion. The presence of internal structural fibres protected by
skin and scales before ultimate destruction is the parsimonious
explanation."

Hogwash.  Under the well-supported developmental/evolutionary model of
Rich Prum, Alan Brush and others, the 'protofeathers' of
_Sinosauropteryx_ are NOT the same as the feathers of juvenile birds.
Modern bipinnate plumulaceous feathers are likely to be derived
structures, having evolved from pennaceous feathers.  The integumental
structures of _Sinosauropteryx_ ('protofeathers') represent the most
primitive stage, being of robust, unbranched, tubular morphology
('Stage I').  Thus, we would not expect these stiff protofeathers of
_Sinosauropteryx_ to behave like the natal down (plumules) of modern
birds.


References

Prum RO (1999).  Development and evolutionary origin of feathers. J.
Exp. Zool. (Mol. Dev. Evol.)  285:291–306

Prum RO, Brush AH (2002) The evolutionary origin and diversification
of feathers. Q Rev Biol. 77:261-295.

Xu X, Zhou Z, Prum RO (2001) Branched integumental structures in
_Sinornithosaurus_ and the origin of feathers. Nature 410:200–204.





On Wed, May 4, 2016 at 4:24 PM, Ben Creisler <bcreisler@gmail.com> wrote:
>
> Ben Creisler
> bcreisler@gmail.com
>
>
> A new paper:
>
> T. Lingham-Soliar (2016)
> Experiments on ostrich decomposition and opisthotonus with implications for
> theropod dinosaurs.
> Journal of Zoology (advance online publication)
> DOI: 10.1111/jzo.12345
> https://urldefense.proofpoint.com/v2/url?u=http-3A__onlinelibrary.wiley.com_doi_10.1111_jzo.12345_full&d=DQIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=qlTFcQqs4A_LQfSQGq-Ngx3_5KoisPyjFE84hjulWN8&s=ai8yA0zXyGeC6m5JtCtpWyLf3r6vh1eY_AxRPewj3rQ&e=
>  
>
> pdf:
>
> https://urldefense.proofpoint.com/v2/url?u=http-3A__onlinelibrary.wiley.com_doi_10.1111_jzo.12345_epdf&d=DQIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=qlTFcQqs4A_LQfSQGq-Ngx3_5KoisPyjFE84hjulWN8&s=Y3nXTd43Cm9s80N3g8fw8VLdNHl9zwhc5YfExXwoy1s&e=
>  
>
>
> Fresh ostrich cadavers were exposed in a natural environment (two on land
> and one in a shallow pool of water) to investigate decomposition and
> possible opisthotonus. The decomposition followed through to skeletonization
> of the ostrich cadavers by maggots, the primary agents of decay. During
> ostrich decomposition, tissue was consumed sequentially from the soft matrix
> tissue of muscles to fibrous and ligamentous tissue (both comprising
> collagen). The feathers (comprising β-keratin) were not consumed. The entire
> decomposition process was completed in 5 days. Towards the latter stages of
> the experiment, the cadavers on land showed stages of strong upward arching
> of the neck which fell short of the opisthotonic posture, while the cadaver
> in the pool showed the classic form of opisthotonus, strongly supporting the
> post-mortem hypothesis of the phenomena. Comparisons are made with
> opisthotonus in the theropod dinosaur, Sinosauropteryx.
>
> News:
>
> https://urldefense.proofpoint.com/v2/url?u=http-3A__phys.org_news_2016-2D05-2Dmodern-2Dday-2Danimals-2Dreveals-2Dinsights.html&d=DQIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=qlTFcQqs4A_LQfSQGq-Ngx3_5KoisPyjFE84hjulWN8&s=ReZjWOD7jY7PJjjALREffm9Gtqyi0a1K18sxyXGHjOk&e=
>  
>