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Re: Dakotaraptor - seriously??



The problem with the bone being misidentified is that it is another
issue in a long line of problems that exist in the Dakotaraptor paper.
The cladistic analysis does not make much sense, especially since it
shows Dakotaraptor and Dromaeosaurus being closely related, when
Dromaeosaurus and Dakotaraptor have very little overlapping material
for such an analysis. The paper presents one, suspiciously resolved
tree, which makes little sense as the analysis it was derived from had
quite a few polytomies. It is likely one tree that they got out of
hundreds. It’s much too clean and is also based on trees generated
many years ago. They also didn’t include the analysis in the
supplementary data, making it harder for other researchers to
replicate the results, an important step in any scientific study.

Furthermore, the paper barely acknowledges the existence of
Acheroraptor, and given that Acheroraptor and Dakotaraptor don't have
overlapping material, this is a problem. The "small morph" of
Dakotaraptor is around the same size of Acheroraptor, and the two may
even be the same genus; this is further exacerbated by the fact that
only one type of dromaeosaurid tooth has ever been found in the Hell
Creek formation, a tooth that's been attributed to Acheroraptor.
Furthermore, very few amniotes have such size disparity in adults,
which both "morphs" of Daktoaraptor have - it's entirely possible that
the two are different species or different genera; I'd say it's likely
that the smaller is Acheroraptor temertyorum; while the larger is
another species of Acheroraptor, given their apparent similarity.

In addition, the paper maintains the validity of Nanotyrannus, a genus
that has been concluded to simply be the juvenile ontogenic stage of
Tyrannosaurus. The paper also has many typos and is hard to understand
at parts.

They also did not properly credit Emily Willoughby’s reconstruction,
and their skeletal and mount are misleadingly posed to make it look
taller than it actually was.

The fact that this paper is of a majorly important feathered dinosaur
makes all of this even worse. Creationists and BANDits like to hop on
the smallest of mistakes made by paleontologists; Archaeraptor is
STILL used by them to disprove the existence of feathered raptors
because of its chimeral nature

Describers of new taxa need to be careful, they need to be rigorous,
and they need to have so much evidence and analysis so as to avoid
this scrutiny and keep the science robust against the sensationalists
who would want the public to believe myths rather than scientific
evidence. If it was just one wrong bone, that would be one thing - but
the paper, on the whole, is not sufficiently scientifically rigorous.


On Mon, Dec 7, 2015 at 5:02 PM, John D'Angelo
<assuming.dinosaur@gmail.com> wrote:
> Misidentifying a piece of turtle plastron would hardly be the only
> questionable aspect of the description of Dakotaraptor. The strict
> consensus tree is completely resolved, despite being based on a data
> set which found several polytomies in Deinonychosauria. I am not alone
> in being skeptical that this is a strict consensus tree. Moreover, the
> large number of MPTs they report--1237--is much larger than the number
> of MPTs for the data set their analysis is based on (30), whereas,
> curiously, the tree length is 1232--only slightly smaller than the
> number of MPTs DePalma et al. report. In other words, I am skeptical
> that DePalma et al. reported their phylogenetic results correctly.
> Perhaps they reported tree length as the number of MPTs, they reported
> only one MPT rather than the strict consensus, or both.
>
> That said, if the type tibia is indeed from a dromaeosaurid, it would
> be the longest dromaeosaurid tibia known. With such a long tibia,
> either it's a five-meter dromaeosaurid with Deinonychus-like
> proportions, or a seven-meter long dromaeosaurid with Utahraptor-like
> proportions. Even if the description is flawed, there's still a
> gigantic dromaeosaurid in the Hell Creek Formation.
>
> On Mon, Dec 7, 2015 at 4:17 PM, Hammer <hammeris1@att.net> wrote:
>> I'm a little shocked that the original researchers would somehow miss this 
>> being a chimera.  How solid is the foundation of this new paper?



-- 
Margaret Dickson
University of Illinois at Chicago
Department of Biological Sciences
Molecular, Cell and Developmental Biology
PhD Candidate