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Illustrations as research tools (was Re: Archaeoraptor et al.)



----- Original Message -----
From: "Stephan Pickering" <stefanpickering2002@yahoo.com>
To: <dinosaur@usc.edu>
Sent: Saturday, September 07, 2002 7:39 AM
Subject: Re: Archaeoraptor et al.


> Mickey Mortimer's 22 April 2001 post re: this taxon,
> then un-named, is what I would point to as an
> excellent, phylogentically rigorous analysis which I
> shall use when the Czerkas compendium arrives.

Please be careful in doing this--Mickey himself admitted that this
description was not based on an actual examination of the specimen, but on
viewing a published drawing (and presumably the original National Geographic
photos). This can be extremely, extremely risky. I am not doubting the
observations that he made off of the illustrations--merely saying that there
is frequently (and almost always) at least some difference between an
illustration (even photos) and the original specimen. Many factors come into
play--lighting, restoration which may not be identified as such in a figure,
camera angle, etc. A case in point is the type for Triceratops flabellatus.
A comparison of Marsh's absolutely beautiful lithographs with the original
specimen shows many points of difference.

I had a wonderfully insightful discussion with Tom Carr several weeks ago,
about the utility of drawings in paleo publications. He made the statement
that inked illustrations depict specimens that do not exist in reality.
Excellent examples are the gorgeous renderings of the skulls of Einiosaurus
and Achelousaurus in Scott Sampson's description of them (Journal of
Vertebrate Paleontology, 1995, 15(4): 743-760). They are based on the best
information possible, and are no doubt pretty accurate. However, there is
not a single specimen that looks anything like that rendering. They are
idealized interpretations of what a whole skull would look like. Sereno and
Novas's Herrerasaurus skull paper is another excellent example (Paul C.
Sereno and Fernando E. Novas, Journal of Vertebrate Paleontology, 1993,
13(4):451-476).

Caution is the rule! Often, sutures are drawn in where none are visible.
Ceratopsians are particularly prone to this, with the heavy fusion in the
cranial sutures. While at the ROM, I spent a good deal of time with the
Arrhinoceratops holotype. I compared the specimen directly with the figures
published by Parks (in the original description) and Helen Tyson (in her
revised description). I will simply state that there are errors, omissions,
and additions in the illustrations of both papers.

Additionally, anything posted on the DML has not been through peer review
(although it does "sorta" go through the process in the course of
discussion). Two paleontologists may have five different interpretations of
an illustration.

Just food for thought. . .

Andy
__________________
Andrew A. Farke
South Dakota School of Mines and Technology, Box P301
501 E. St. Joseph St.
Rapid City, SD  57701

Phone: 605-394-2817

E-mail: andyfarke@hotmail.com