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RE: Pterosaur Help



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





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"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
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        Silvio.Renesto@unimi.it
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