[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Fwd: Fw: Error Condition Re: Re: Azhdarchidae (Pterosauria) review monograph (free pdf)

Rescued from Listproc's unrecognized subscriber filter:

From: Steven Vidovic <steven.vidovic@port.ac.uk>
Date: Tue, 19 Aug 2014 08:55:51 +0100
Subject: Re: Azhdarchidae (Pterosauria) review monograph (free pdf)
To: Michael Habib <biologyinmotion@gmail.com>
Cc: dinosaur mailing list <dinosaur@usc.edu>, bcreisler@gmail.com

I should point out that my error values were calculated from
Averianov's data divisions. If you lump them into the two groups that
I did the error rises to a whopping 11! making the lower 95th
percentile for "nearshore marine" 16.44, and the upper for
"terrestrial" 31.24. The values for "nearshore marine" were 38, and
the "terrestrial" 16. This makes it pretty clear that the data is not
sufficient to say with any certainty what environment they occupied.

On 19 August 2014 00:44, Steven Vidovic <steven.vidovic@port.ac.uk> wrote:
> In response to Mike's point... I'd consider "nearshore marine" to be
> coastal plain, estuarine and coastal marine, in which case that is 70%
> of the data. I've also been through and calculated the standard errors
> to see if his small dataset would stand up to scrutiny. The lower 95th
> percentile for "nearshore marine" is 36.88, whereas the upper of
> "terrestrial" is 17.12. So there is no overlap. The comparator dataset
> is very poor though, with lots of error overlap between Averianov's
> divisions and the total data being being about a quarter of the
> azhdarchid dataset. Considering the conclusions are at odds with the
> previous work by Witton and Naish '08, the new study should have been
> a bit more rigorous in my opinion. The interpretation of the graphs
> are very vulnerable to subjectivity, as we can see with the difference
> of my opinion to Mike's! Where are the significance values, the
> hypotheses and null hypotheses?!
> It would have been interesting to see the taphonomy quantified too, to
> support his statement about the material not being transported.
> My interpretations of this would be that azhdarchids are far more
> cosmopolitan than previously suggested, with a high number of
> specimens occuring in all environments, but with a particular bias
> towards coastal environments. However, there are far more coastal
> deposits, and the terrestrial material had to get there somehow!  I
> would like to see a far more rigorous study using predetermined
> hypotheses, cross referencing taphonomic, sociological, lagerstatte
> and specimen abundance data.
> On 18 August 2014 18:45, Mike Habib <biologyinmotion@gmail.com> wrote:
>> Thanks to Ben, as always, for the heads up on a new paper.
>> I just read through the paper this morning, and it is a rather exhaustive 
>> review of localities and specimens, which is really useful. I am, however, 
>> perplexed by the comment that azhdarchids were “most common in nearshore 
>> marine paleoenvironments” (in the abstract and the discussion of the 
>> manuscript) given that 65% of the remains are from environments other than 
>> coastal marine. Sure, the 35% coastal marine is the single largest category 
>> given the way the taphonomic environments are split up, but if you were to 
>> look at them as ecological settings, then the coastal systems would be split 
>> into several categories and the lacustrine and fluvial plain deposits (for 
>> example) might very well have been pretty similar places to live. Perhaps I 
>> am missing something critical here (as I don’t do a lot of taphonomy), but 
>> it seems like the breakdown really says “usually preserved by water, and can 
>> be inland or marine, because there were all over the
>> Thoughts?
>> —Mike
>> Michael Habib
>> Assistant Professor of Cell and Neurobiology
>> Keck School of Medicine of USC
>> University of Southern California
>> Bishop Research Building; Room 403
>> 1333 San Pablo Street, Los Angeles 90089-9112
>> Research Associate, Dinosaur Institute
>> Natural History Museum of Los Angeles County
>> 900 Exposition Blvd, Los Angeles, CA 90007
>> https://plus.google.com/+MichaelHabib/about
>> biologyinmotion@gmail.com
>> (443) 280-0181
>> On Aug 18, 2014, at 7:31 AM, Ben Creisler <bcreisler@gmail.com> wrote:
>>> Ben Creisler
>>> bcreisler@gmail.com
>>> A new paper in open access:
>>> Alexander Averianov (2014)
>>> Review of taxonomy, geographic distribution, and paleoenvironments of
>>> Azhdarchidae (Pterosauria).
>>> ZooKeys 432: 1–107
>>> doi: 10.3897/zookeys.432.7913
>>> http://www.pensoft.net/journals/zookeys/article/7913/review-of-taxonomy-geographic-distribution-and-paleoenvironments-of-azhdarchidae-pterosauria-
>>> The taxonomy, geographic distribution, and paleoenvironmental context
>>> of azhdarchid pterosaurs are reviewed. All purported pteranodontid,
>>> tapejarid, and azhdarchid specimens from the Cenomanian Kem Kem beds
>>> of Morocco are referred to a single azhdarchid taxon, Alanqa saharica.
>>> The four proposed autapomorphies of Eurazhdarcho langendorfensis from
>>> the lower Maastrichtian Sebeş Formation of Romania are based on
>>> misinterpretations of material and this taxon is likely a subjective
>>> junior synonym of Hatzegopteryx thambema. Among 54 currently reported
>>> azhdarchid occurrences (51 skeletal remains and 3 tracks) 13% are from
>>> lacustrine deposits, 17% from fluvial plain deposits, 17% from coastal
>>> plain deposits, 18% from estuarine and lagoonal deposits, and 35% from
>>> costal marine deposits. Azhdarchids likely inhabited a variety of
>>> environments, but were abundant near large lakes and rivers and most
>>> common in nearshore marine paleoenvironments.
>>> News story:
>>> http://www.pensoft.net/journals/zookeys/article/7913/review-of-taxonomy-geographic-distribution-and-paleoenvironments-of-azhdarchidae-pterosauria-