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Zootaxa iguanodont paper



My recent papers on iguanodont taxonomy have resulted in Norman becoming 
more active these days including his new paper in Zootaxa. Because the paper 
casts some doubt on the quality of my research, includes some problems, and 
it may be awhile before I respond, Iâm posting these notes. 

The Zootaxa paper implies I made a serious mistake regarding the unusual 
iguanodont dentary R8131, which belongs to a partial skeleton. Normanâs claim 
is that examination of the actual specimen shows that the original 1874 l
ithographic illustration is in error. Actually it is Norman who slipped in 
relying on what is left of the specimen. The original illustration is one of 
those magnificent Victorian near photo quality images executed and printed at 
actual scale (by Mintern Bros apparently). Far from being in error, it is the 
only visual documentation we have of what the dentary actually looked like 
when it was fresh out of the ground. I came upon this image entirely by 
accident while trying to verify the spelling of I. hoggii, and paid it little 
mind assuming it was yet another iguanodont dentary of no great import until 
repeated viewings led me to eventually realize that there was something quite 
odd about it. Specifically, the anterior most teeth were very reduced in 
size, and were preceded by a very long diastema of the type generally not 
found until much more derived and later hadrosaurs. Note that I keep saying 
WERE.

Norman seems to claim that there is only one wee tooth in the original 
illustration, and that it was spuriously placed there for some reason because 
the tooth is anomalous relative to the other teeth, and is not on the specimen 
these days. Actually there WERE several teeny teeth -- the first were just 
the roots in situ according to the 1874 illustration, the most posterior was 
complete but overemerged and primed to fall off and be lost (may still be 
in the collections somewhere). There is no reason to think the Victorian 
illustrator made these up, why would he do that? They are illustrated because 
they were there. The roots are so small that they are easily missed unless one 
is looking at the original print or a sufficiently good copy, the image in 
the Zootaxa paper is too poor for the viewer to be aware of them. The 
missing small tooth is therefore not anomalous, the anteriormost teeth were 
very 
reduced. Such itsy bitsy teeth are never present so far posterior in 
iguanodonts without a diastema, instead the teeth at the middle of the tooth 
battery 
are big. They would be so reduced only if they make up front end of the 
tooth row. The little teeth are no longer where they originally were for the 
simple and sad reason that the specimen suffers from untreated pyrite disease 
and has been shedding pieces for over a century. Normanâs own illustration 
clearly shows that extensive erosion has led to the loss of the diastema and 
the tiny anteriormost teeth -- what he correctly labels as broken obviously 
was not broken in the 1870s. It is fortunate that a fine lithographic print 
(by C L Griesbach) of ye old super detailed illustration by a highly skilled 
and probably underpaid artist survives to show the true morphology of the 
highly distinctive element. Score another one for us ace illustrators. 

Norman also claims that R8131 was originally deeper than it now seems. 
There is no evidence of significant loss of depth of the dentary in the 
original 
figure, and the shallow height of the medial dentary wall between the 
alveolar parapet and Meckelian canal confirms the dentary was long and low, 
rather like Dollodon and not like 28660. The unusually strong antero-dorsal 
pitch 
of the border between the alveolar parapet and the medial wall of the 
dentary also indicates that the tooth battery was constricted to a posterior 
position.   

The Zootaxa paper does not make it at all clear in anatomical or 
stratigraphic terms why R8131 and the associated skeletal elements including 
the super 
massive arm should be referred to Hypselospinus fittoni. R8131 et al were 
found in a shoreline quarry below the high tideline, and may be older than 
the quarry that produced the type H. fittoni. One thing I have trying to 
emphasize is that when it comes to taxonomy pay attention to the bloody 
stratigraphy because species do not last long. It is now known that the species 
of 
centrosaurs, chasmosaurs, corythosaurs, lambeosaurines were limited to 
distinct levels of the Dinosaur Park formation. Before referring specimens to a 
known species it must be first demonstrated they are from the same level of a 
formation as the type. Norman keeps referring to specimens being in the 
Valanginian, but the stage lasted 6 or 7 million years, what is needed is 
whether 
the specimens are from the lower, middle or upper Valanginian. Nor does the 
Zootaxa paper cite Naish & Martill 2008, who showed that the Old Roar 
Quarry animal is not part of B. dawsoni. 

And it looks like Norman wants to sink Dollodon into Mantellisaurus (the 
latter is not mature, but is not much smaller than the former). That wonât 
fly. Copy the skulls of the two species to the same scale -- they are virtually 
identical in length â and there is no way they are the same genus because 
the proportions are so radically different, and it is not possible to grow 
one into the other without requiring the reduction of major elements in order 
to allow the expansion of others. Likewise reproducing the feet of the two 
types to the same scale shows they are dramatically different and cannot be 
ontogenetically derived from one another.  

The Zootaxa paper appears to continue to make the mistake of over 
simplifying Euroiguanodont taxonomy and evolution, with just two genera and 
species 
in the lower Early Cretaceous and another two higher up. Iguanodont evolution 
was a lot more complicated and bushier than that. 

GSPaul 

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