RE: Pterosaur Help

[Silvio Renesto <renesto@mailserver.unimi.it>]

At 19.10 27/11/01 +0100, Fabio wrote:
> Dear Tracy,
>
> <<The taxonomy of early pterosaurs is a mess. i suggest to be careful in
> accepting as correct the descriptions you find in literature and to look
>  A T  T H E  S P E C I M E N S!!!>>
> <Unfortunately, this is the main thing WE can do. IF we can't rely on the
> authors whom can we rely on? How should we know if they are misleading us?
> WE HAVE to rely on the authors to correctly identify what we are reading and
> seeing. This includes making the illustrations as accurately as possible. WE
> all can't travel the world, look at EVERY specimen, so we have to rely on
> the written word. IF we can't rely on the written descriptions what good is
> it to write them? Or even believe what is being written? Or for that matter,
> what any scientist has to say?>

If I may get into this for a couple of considerations,  experience tells 
that many descriptions are OK but one must be cautious anyway, 
especially  when descriptions are not accompanied by very good drawings of 
the material as preserved, and possibly photos. Scientist try to be 
objective (at least I hope), but anything  it is written is an 
interpretation. The map  is never the territory, despite how accurate it 
is. Sometimes, it may happen that one (including myself)  sees what he 
believes or wants to see, in good faith, or is sidetracked by many factors. 
Literature may be very far from the truth  in some (hopefully few ) 
cases.  Thus, if you have not the possibility to check the 
specimens,  check the photos/drawings of the specimens "as preserved" and 
try to judge the consistency with the descriptions/reconstructions, before 
accepting them.
I do not want to offend anyone, so I do not make identifiable examples here 
, but I have a reprint in which the author's description clearly contrast 
with the drawings of the author himself!!
This is because he was probably biased by an accepted paradigm about the 
shape of a structure and did not realize that in that specimen the paradigm 
could not be applied.  So he despised evidence in favour of  paradigm.


> I mean that we cannot accept ACRITICALLY the published descriptions.
> Everybody can make mistakes. Thus, we must read ALL the published papers
> concerning a taxon and compare the different descriptions. Furthermore, if
> you are doing a matrix of characters and you have doubts or there is
> something unusual in the state of a character, you must check that
> character in the specimen. Some mistakes become general paleontological
> culture because after the first description nobody else checked them again
> in the specimen.


The problem is bigger when we are confronted with something new or 
unexpected or too poorly preserved to allow a correct identification take 
for instance Megalancosaurus  ;-)
In its first description the bizarre pattern of the carpus was not 
recognized as it was, because there was little experience about such a 
strange pattern , so instead of recognizing odd  elongate carpals, it was 
written that the ulna was splitted in two parts in its distal end.  It 
appeared in the literature that Meg. had a birdlike  semilunate carpal. 
This was simply due to the hanging  hypothesis of bird relationships. 
Subsequently assumption was taken for granted and was reproduced in a book 
on vertebrate origin and evolution despite that, it was clearly visible 
even in the photos of the first descriptions that such a feature was not 
present.
When better preserved material become available, It was possible to realize 
how really the carpus was,  and PUBLISHED PHOTOS  (now also online) enable 
anyone to check this.

Sorry for the intrusion and length.

                                                        Silvio





_
"Who looks for Knowledge increases every day;
                Who looks for Wisdom decreases every day"

                                                Lao Tzu

Silvio Renesto

Dipartimento di Scienze della Terra
Università degli Studi di Milano
Via Mangiagalli 34
I 20133 Milano
Italy
phone +39-02-58355511
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e-mail:  renesto@mailserver.unimi.it
        Silvio.Renesto@unimi.it
have a look at our Triassic  website at
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