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Re: Australian dinosaur "stampede": identity of large track-maker



Stephen: regarding your statement about the originality of the project:

"I actually think this is a fair contention, though not an argument in
itself against the conclusions made by Romilio and Salisbury. For this
PhD project to have been instigated and undertaken, the authors would
essentially have had to take up the position that the stampede
interpretation presented by Thulborn and Wade (1984) was partially or
totally incorrect or incomplete."

>From what I understand, the PhD project had initially started as an
investigation into dinosaur limb mechanics and behaviour, and what better
way to do that then look at footprints! A documentary team expressed
interest in animating the stampede around the same time, so Romilio
offered to help in correctly animating how these animals would have run.
He started analysis of the tracks, interested mainly in their topography
and what it meant for foot placement patterns, weight distribution etc?
but then ran into problems when the patterns he identified did not match
the papers and theories he'd read.

He was advised to start from scratch i.e. Pretend that it was a new,
undiscovered site, and interpret what he saw without the bias of previous
interpretations. That is when he came up with this new theory. It has
headed his project in a direction he didn't necessarily want it to go,
because at the end of the day he's just interested in studying limb
mechanics and behaviour.



On 31/01/13 1:55 AM, "Stephen Poropat" <stephenfporopat@gmail.com> wrote:

>Dann: If you read the abstract alone it may seem like an ad hominem,
>but Thulborn does focus on the method, not the men, in the paper (and
>in the abstract, mostly), so I think his critique is sound.
>
>David: It's strong wording, but if you replace "fabricated" with
>"extrapolated" it doesn't capture what Thulborn is getting at - that
>the heels of the footprints were reconstructed, seemingly without
>basis, to act as crucial data points in a multivariate analysis.
>
>Regarding this version (2013) of Thulborn's paper, the most notable
>discrepancy between it and the previous Cretaceous Research version
>(2011) is the omission of the closing paragraph:
>
>"Finally, it is pertinent to mention that Romilio and Salisbury may
>have a special interest in overturning the existing interpretation of
>Lark Quarry. They did not disclose that one of them (AR) is
>undertaking a reappraisal of the Lark Quarry dinosaur tracks as a PhD
>research project supervised by the second author (SWS). If the
>findings of that research were merely to corroborate the existing
>interpretation of Lark Quarry, they might seem to lack the originality
>required to justify the award of a degree. In other words, it might
>seem imperative that these authors should find and repair substantial
>faults in the existing interpretation or, better still, that they
>should overturn it completely and introduce an entirely new
>interpretation."
>
>I actually think this is a fair contention, though not an argument in
>itself against the conclusions made by Romilio and Salisbury. For this
>PhD project to have been instigated and undertaken, the authors would
>essentially have had to take up the position that the stampede
>interpretation presented by Thulborn and Wade (1984) was partially or
>totally incorrect or incomplete.
>
>I have many more problems with Romilio and Salisbury's (2011, 2013)
>interpretations of the Lark Quarry track site than I do with Thulborn
>and Wade's (1979, 1984). Regarding Romilio and Salisbury (2013)
>specifically:
>
>1) The synonymisation of Wintonopus and Skartopus was made on the
>basis that ³some² deeper footprints of Wintonopus appear to have
>Skartopus-like footprints within them and vice versa. Romilio and
>Salisbury's Figure 11, which is the only figure cited as showing
>Wintonopus footprints within Skartopus footprints is far from
>convincing - the middle toe is incredibly long compared to the
>holotype (Figure 9). No scale bars are included in the supplementary
>figures, meaning that meaningful comparisons are not really possible.
>With respect to the opposite situation, i.e. Skartopus tracks within
>Wintonopus tracks, maybe some of the (smaller) Skartopus trackmakers
>happened to step within the footprints of the (larger) Wintonopus
>trackmakers because a lot of animals were running, all at the same
>time, maybe in a stampede? It cannot be denied, for example, that some
>Skartopus tracks overprint the Tyrannosauropus tracks (Thulborn &
>Wade, 1984: Pl.17)...
>
>2) The idea of having four differently sized track generators making
>tracks at times of four different (and convenient) water levels seems
>to be a contortion act to fit the data to a preconceived notion, i.e.
>that the majority of the footprints (excluding the two larger
>ornithopod sets and the large theropod/ornithopod set) were not made
>at the same time; i.e. that the interpretation of Thulborn and Wade is
>incorrect. Just how rapidly was the water level changing, and what
>sedimentological evidence is there of such rapid and repeated changes?
>If the water level was changing so much, and the environment was a
>high-energy one, why are the footprints so coherent? They look more
>like footprints made in fresh, ready-to-set cement than footprints
>made in subaqueous conditions.
>
>3) Why would so many of the tracks be so deep if they are swimming
>traces? The depth of the footprints seems to suggest that the majority
>of these animals were not being supported by very much (if any) water
>at all. And the depth of the tracks is probably only able to be
>under-estimated (due to incomplete removal of sediment) rather than
>over-estimated, so the majority are probably deeper than they appear.
>
>4) The method for determining that a series of footprints were made by
>a single individual is not clear. There are a _lot_ of footprints at
>this site - I have seen it, and it would take a lot of work to discern
>the precise number of trackmakers, let alone the footprints which
>comprise individual series.
>
>5) Finally, the idea of a ²mixed herd² of ornithopods and theropods is
>not an issue for three reasons:
>a) If the Skartopus trackmakers were theropods, this does not
>necessarily imply that they were carnivorous
>b) If the Skartopus trackmakers were carnivorous theropods, they were
>clearly (on average) smaller animals than the Wintonopus trackmakers
>and probably would not have been a threat;
>c) If the Skartopus trackmakers were carnivorous theropods, and were a
>threat to the Wintonopus trackmakers, and if the Tyrannosauropus
>trackmaker was a hungry theropod, then all small trackmakers were
>panicking and would have had escape rather than food as their
>immediate objective.
>
>The last paragraph of Romilio and Salisbury's discussion (page 116),
>where the authors claim that they may be viewed as ³iconoclasts² by
>some scientists and members of the public for presenting a different
>interpretation of this site is spot on (and will now seem prescient
>based on the "official" publication dates of Romilio and Salisbury
>(January 8, 2013) and Thulborn (January 29, 2013). However, it is spot
>on for the wrong reasons. They probably will be viewed as such, not
>because of their conclusions per se, but because of the way in which
>their interpretations were presented, and the methods which were
>employed to arrive at their conclusions. In general, if the aim is to
>overturn a scientifically well-supported, parsimonious interpretation,
>it must be done properly. Thulborn has called Romilio and Salisbury
>out on their methodology, and I think he is justified in doing so.
>Undermine the method and you undermine the interpretation.
>
>Presently, I am of the opinion that Thulborn and Wade's interpretation
>is still better-supported by the data, supported by more rigorous
>science, and more parsimonious than the interpretation made by Romilio
>and Salisbury. It has distressed me greatly to see various media
>sources and blogs accepting Romilio and Salisbury's papers'
>conclusions essentially uncritically and without contacting any other
>palaeontologists for their two cents or referring explicitly to
>Thulborn and Wade's papers.
>
>If I am in error in any of my statements / questions / whatever,
>please let me know. I would like our version of the events that led to
>the formation of Lark Quarry to be as close to the actual events as
>possible.
>
>Cheers,
>
>Steve
>
>On Wed, Jan 30, 2013 at 3:23 PM, David Marjanovic
><david.marjanovic@gmx.at> wrote:
>>
>> > Those iconoclastic claims are examined here and are shown
>> > to be groundless: they are based partly on misconceptions and partly
>> > on fabricated data that have been assessed uncritically using
>> > quantitative measures of questionable significance.
>>
>> Fabricated data?
>>
>> What the vertical gene transfer?
>
>
>
>
>--
>Dr. Stephen Poropat
>
>Postdoctoral Research Fellow
>Uppsala University
>Villavägen 16
>SE-752 36 Uppsala
>Sweden
>
>Research Associate
>Australian Age of Dinosaurs
>PO Box 408
>Winton 4735
>Australia
>