Re: Princeton Field Guide: a different take

[Zach Armstrong <zach.armstrong64@yahoo.com>]

Aside from the disputes in regards to the taxonomy in the Princeton Field Guide 
to Dinosaurs (hereon abbreviated as PFGD), I am actually somewhat disappointed 
in the skeletals that are contained therein for some taxa and the lack of 
skeletals for some both well-documented and well-described taxa. Because my 
interest is mainly in sauropods, I will focus on those taxa.

I am somewhat irked by the fact that Greg Paul argues that splitting and 
lumping 
of genera and species should at least be consistent, whilst his criteria for 
including (or excluding) skeletals for certain taxa is not, to say the least, 
consistent. Similarly inconsistent is the rigorousness with which some taxa are 
restored versus other taxa. Case in point: the skeletal for *Supersaurus* shows 
the state of preservation of the fossil material (such as that some skeletal 
elements are incomplete or missing and are shown as such). However, other taxa, 
such as *Rapetosaurus* are not restored in the same manner. For instance, many 
of the caudals of *Rapetosaurus* are missing and yet are restored as being 
known. Also, most of the cervical vertebrae in *Rapetosaurus* are known only 
from their centra, as their neural arches are missing in many of them. Yet, 
from 
Greg's skeletal, you'd never know that since they are all shown to be 
completely 
preserved...

On the other hand, well-documented taxa that have been well-described and 
figured are not given skeletal treatments. For instance, while we get a 
restoration of the skull of *Malawisaurus*, the rest of the skeleton is not 
restored even though it is known from a nearly complete postcranial skeleton 
including much of the cervical, dorsal, sacral and caudal series not to mention 
appendicular elements--the only thing really lacking is the ilia and pubis. 
Similarly, *Phuwiangosaurus* is known from well-described and documented 
remains 
(including much of the cervical, dorsal, sacral and caudal series as well as 
all 
the appendicular elements), but no skeletal treatment is given for this taxon 
either. In both cases, these taxa represent a relatively basal part of the 
titanosaur radiation and would give a better idea of  what basal titanosaurs 
looked like but are nonetheless lacking.

Similarly odd is why *Huabeisaurus* is given a skeletal treatment, yet is known 
from comparatively few elements when compared to *Malawisaurus* and 
*Phuwiangosaurus*. In the original description, *Huabeisaurus* is listed as 
being known from only 4 cervical elements, 2 of which are figured. 
*Huabeisaurus* is only known from 5 dorsal vertebrae and 21 caudal vertebrae as 
well as its sacrum and pelvis and appendicular elements, and as such is no more 
complete (in fact, less complete) than *Malawisaurus* and *Phuwiangosaurus*, 
yet 
a skeletal is provided for it and appears to show a lot more elements than are 
actually known. What it appears to me is that the skeletal of *Huabeisaurus* 
was 
drawn from photographs of the mounted skeleton, which much of its elements 
appear to be sculpted to fill in the missing gaps (look at the anterior 
cervical 
vertebrae for instance in pictures of the mounted skeleton that are available 
on 
Flickr). This makes me wonder how accurate other skeletals are of species that 
appear to be based off of mounts in which the material therein has not been 
published on in any science journal of which I am aware. For instance, the 35m 
long "Mamenchisaurus sinocanadorum" skeletal based off of the huge mounted 
skeleton is questionable, because, as far as I am aware it has not been 
described. If we're going off mounted skeletons to provide references, why is 
there no skeletal based off of the 37m long *Argentinosaurus* mount at the 
Fernbankn museum of natural history? Much of the material in the 
*Argentinosaurus* skeletal is restored and is in general too big, we know that 
*because* of the published material. In the case of "Mamenchisaurus 
sinocanadorum" mount, how do we know this isn't similarly speculatively 
restored 
as in the case of *Argentinosaurus*? If we were to go ff skeletal mount, 
*Argentinosaurus* would mass a lot more than "M. sinocanadorum", yet the latter 
is considered the largest dinosasur known from good material in PFGD.

Aside from this, at least one skeletal appears to be scaled incorrectly, and 
the 
entry for that taxon lists it as much larger than it probably was based off 
known material. I speak of *Futalognkosaurus* which is shown as quite a bit 
larger than the *Giraffatitan* next to it in the section on gigantism in PFGD. 
Yet both from information in the paper describing the anatomy of 
*Futalognkosaurus*, it is apparent it was at least smaller than the HMN SII 
specimen and proabably a good deal smaller than HMN XV2. The dorsal column of 
*Futalognkosaurus* was probably just under or around 3m long, yet in Greg's 
1988 
paper on *G. brancai* the  dorsal column was estimated to be over 3.7m long. 
Furthermore, a recent abstract released in 2008 said that previous estimates of 
the length of *Futalognkosaurus* were overstated, and that the length from axis 
to sacrum was ~11.9 m, and that the total length of *Futalognkosaurus* was 
about 
13 m excluding the tail (which may still be a fairly liberal estimate of its 
length). Yet, going off the table in Greg's 1988 paper, the HMN SII specimen of 
*G. brancai* was over 14.8m excluding the tail. That means that 
*Futalongnkosaurus* was almost 2 m shorter (excluding the tail) than a 
not-yet-fully-grown *G. brancai*, but you'd never know that from the diagram in 
PFGD. 


Also odd is that the taxon *Uberabatitan* is nowhere listed or even referred to 
anywhere in PFGD, even though it is known from reasonably good material.  There 
are other issues that I will not go into, but I'll leave it at  that. 
All-in-all, I'm not too impressed with PFGD. However, I will admit  that it is 
nice to see a lot of skeletals for taxa that I haven't seen  before. I just 
hope 
these can be vouched for better than some of the  sauropods...

I also find it it odd that Greg says that a larger field guide would not be 
marketable. The Sibley Guide to Birds contains 810 species and is over 540 
pages 
(thats over 200 more pages than in PFGD) and has sold very well. Especially odd 
since only about 400 of those are actually illustrated and the rest are given 
rather cursory treatments. Even the Princeton Field Guide "Sharks of the 
World", 
which contains 453 shark species--all illustrated in both color and in 
black-and 
white, often with multiple views---and is 368 pages, and has more information 
on 
each species of shark than each species of dinosaur has in PFGD.


Regards,

Zach



----- Original Message ----
From: "Thomas R. Holtz, Jr." <tholtz@umd.edu>
To: DML <dinosaur@usc.edu>
Sent: Fri, October 1, 2010 7:40:37 AM
Subject: Princeton Field Guide: a different take

Greetings,

My copy arrived yesterday, and thankfully was not ruined by the horrendous 
rainfall we had.

I know that the DML is always WAY concerned about taxonomy, but there is a lot 
more to this book than that.

As in: dozens of hitherto unpublished Greg Paul skeletal restorations!! Some of 
speices which have not-to my knowledge-had actual
skeletal restorations before.

At some point in my mythical copious free time I need to spend a few hours with 
a flat bed scanner: next year's GEOL 104 students
will be seeing a lot new taxa showing up on PowerPoints and tests...

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu    Phone: 301-405-4084
Office: Centreville 1216            
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661        

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:    Thomas R. Holtz, Jr.
            Department of Geology
            Building 237, Room 1117
            University of Maryland
            College Park, MD 20742 USA