(my dance with dinosaurs)
page 5
BUILDING A BETTER STEGOSAURUS
This is an ITC Stegosaurus, built
in 1957. As I recounted on the first page, this was my brother's
model
and I had to do some restoration of missing plates when I dug it out of
storage in the early 1990's. Since then I have put together new
versions of the
Tyrannosaurus and Brontosaurus kits in this series, re-released by
Glencoe
Models in the 1990's. In doing so, I tried to make them more
accurate in reflecting modern thinking regarding dinosaur posture as
well as improving detail in many of the rather crudely cast
pieces. I have had a reissued Glencoe kit of this beast in
my closet for a long time, and recently decided
to see if I could make it into a more modern 21st century Stegosaurus.
NEW AND IMPROVED STEGOSAURUS
When I opened the box, my primary plan was to raise the tail off
the ground as modern thinking says they weren't tail draggers. I
also wanted to make the tail spikes into a more horizontal
"thagomizer" instead of the old-fashioned upright configuration.
Then
I
took
a
closer look at the pieces and realized how much work was
ahead. As is typical of all of the kits in the ITC series, the
vertebrae are narrow and oval rather than thick and round. The
articulations between the vertebral facets are only vaguely represented
and if anyone really wanted to fix this central issue, they would
probably be better off sculpting an entire model from scratch. I
decided to be content to try to enhance the disc demarcations between
the bones and in a few places cut deeper grooves to depict intra-spinal
articulations, but not to be obsessive about it.
I always considered the skull of the Stegosaurus to be its blandest feature, and this old model is probably the reason.
2. Pin between tail and sacrum.
3. Old femur insertion removed and puttied.
NEW AND IMPROVED STEGOSAURUS
I always considered the skull of the Stegosaurus to be its blandest feature, and this old model is probably the reason.
There is very little detail in the
original. A seam runs where there should be an opening and the
mandible looks more like a lifeboat than a jaw. I
added some putty and went to work with my Dremel. The orbits and
nostrils were enlarged and I added fenestrae behind and
above the eyes, as well as removing everything in the lower jaw that
didn't look like a jaw. I also carved out the underside of the
skull so the poor thing would be able to swallow.
This is the new head, with all of the added openings
1. New disk spacers from number
tabs.
This is the new head, with all of the added openings
I cleaned up the neck and
accentuated the cervical ribs. I thought about adding osteoderms
under the neck and making new ribs from sprue, but decided that would
be too much trouble. I may add them later.
As is typical of these kits, the ribs needed work.
There has been some controversy over the position of the front limbs of Stegosaurus. Some think that they are bent at the elbow and others believe that the front end was perched on fairly straight legs. Either way, the head is supposed to be held fairly low, so I decided to stick with the bent position.* While I didn't plan to do much in the way of putting the legs in a different pose, they needed a LOT of work. The parts of the front legs didn't really line up with the joints and the rather crude casting quality made it tough to tell which bones were which. At the elbows I had to decide how to show the radius and ulna as separate bones rather than a single messy clash of shapes. Large seams that were almost extra joints had to be filled with putty. Then there were the feet... They consisted of softly formed clusters of toes with no delineation at all showing interphalageal joints. I tried to deepen the gaps between the toes and used a cutting tool to make some rudimentary lines suggesting toes, but they still pretty much look as if this Stegosaurus is wearing mittens. The feet are not the strongest part of this model.
*As will be seen below, after putting the whole thing together, I changed my mind.
As is typical of these kits, the ribs needed work.
There isn't anything to set the
ribs apart from the vertebrae and there is a pretty obvious seam
between
the parts. In the second image I show a sharpie line that gives
an idea of where to apply the Dremel. The plastic is fairly soft
and shreds easily, which makes precise cuts tough. Nonetheless,
after a lot of cutting, puttying and sanding, there is at least a
suggestion that there is a dividing line between the ribs and the
vertebrae to which they attach.
There has been some controversy over the position of the front limbs of Stegosaurus. Some think that they are bent at the elbow and others believe that the front end was perched on fairly straight legs. Either way, the head is supposed to be held fairly low, so I decided to stick with the bent position.* While I didn't plan to do much in the way of putting the legs in a different pose, they needed a LOT of work. The parts of the front legs didn't really line up with the joints and the rather crude casting quality made it tough to tell which bones were which. At the elbows I had to decide how to show the radius and ulna as separate bones rather than a single messy clash of shapes. Large seams that were almost extra joints had to be filled with putty. Then there were the feet... They consisted of softly formed clusters of toes with no delineation at all showing interphalageal joints. I tried to deepen the gaps between the toes and used a cutting tool to make some rudimentary lines suggesting toes, but they still pretty much look as if this Stegosaurus is wearing mittens. The feet are not the strongest part of this model.
*As will be seen below, after putting the whole thing together, I changed my mind.
A quick look at the hips and pelvis
revealed what is probably the most amazing shortcut and incredible
inaccuracy in this kit. One of the basic and defining
characteristics of all dinosaurs is the open acetabulum, or hip
joint. The opening is formed where the three bones of the pelvis,
the pubis, ilium and ischium come together and the femur, or thigh bone
is supposed to fit into that gap. This model shows the femur
butted into the underside of the iliac crest and there is no hip joint
at all! The rest of the pelvis is also a mess. Stegosaurus
is an ornithischian dinosaur, meaning that its pubis has an extension
that runs backwards along the ischium rather than projecting forward in
a large boot-shaped bone as seen in theropods such as the
Tyrannosaurus. In looking at this model I could never understand
how the ornithischian pelvis was constructed and it was now evident why
it always seemed so confusing. The iliac rest looked pretty good
aside from the slots on the underside for the misplaced femurs, but
the lower pelvis parts are pretty much devoid of detail and consist of
little more than Y-shaped blobs representing the smushed-together
ischium and pubis.
From the old version, the lack of a hip joint can be seen at the upper arrow and the fused, blobbish ischium and pubis is shown at the lower arrow.
From the old version, the lack of a hip joint can be seen at the upper arrow and the fused, blobbish ischium and pubis is shown at the lower arrow.
I decided that I would need to get
rid of the slots on the underside of the iliac crests, make heads for
the femurs, and while I was at it, show the difference between the
pubis and the ischium,
In this picture a Sharpie has been
used on the ischium/pubis to show the dividing line between the bones
and where the acetabulum will be. I have also cut the locating
tab off of the end of the femur so that I can replace it with a
plausible femoral head.
This kit has really heavy sprue
and a couple of short lengths attached to the ends of the femurs
make a nice basis for a head to articulate with an open acetabulum.
Some putty has been applied to the
femurs and the demarcation between the pelvic bones as well as the open
hip
sockets are now pretty obvious. There was still some
drilling to do and those slots on the iliac rests still needed to be
removed, but these parts make a much better pelvis!
Finally it was time to work on the tail, which was really the part I originally expected to alter the most. The way the tail joined the body would need to be altered in order to have it up in the air instead of dragging on the ground. The change in angle needed to happen over several inter-vertebral joints rather than in one place to avoid it appearing that the poor thing simply sat down too hard and broke it. I began by cutting through the discs between the first five vertebrae at the base of the tail and inserting spacers made from number tabs scavenged from the model. Once the discs were cut, the articulations between the neural spines bent easily. I drilled a couple of holes into the center of the first few vertebrae and into the sacrum to allow me to insert pins to hold everything together.
Finally it was time to work on the tail, which was really the part I originally expected to alter the most. The way the tail joined the body would need to be altered in order to have it up in the air instead of dragging on the ground. The change in angle needed to happen over several inter-vertebral joints rather than in one place to avoid it appearing that the poor thing simply sat down too hard and broke it. I began by cutting through the discs between the first five vertebrae at the base of the tail and inserting spacers made from number tabs scavenged from the model. Once the discs were cut, the articulations between the neural spines bent easily. I drilled a couple of holes into the center of the first few vertebrae and into the sacrum to allow me to insert pins to hold everything together.
2. Pin between tail and sacrum.
3. Old femur insertion removed and puttied.
All of the gaps were then puttied
and sanded.
Finally, it was time to alter the
"thagomizer". The attachment tabs on the spikes were bent to
allow an open angle between them and they were glued in place.
At this point, the basic skeleton
was complete and all that remained was the addition of the
plates. The largest plate, at the base of the tail, just didn't
fit on its tab without running into the next tab and following
plate. I drilled a hole into it and another into the neural spine
and used wire to attach it. That worked well and it occurred to
me that if I attached ALL of the plates that way, I could have them
standing up or folded over, as the earliest depictions of
Stegosaurus showed them sloped downward like roof tiles.
However, that seemed like way too much work and I knew if I played with
them too much, they would eventually break off and be really hard to
reattach. So the rest are glued onto the tabs projecting from the
neural spines.
While I got down to work painting it with a coat of black primer, dark brown mixed with red for a second coat and a misting of medium gray with flat black washes and a little bit of medium brown dry brushing, I began to have misgivings about the way it looked. As I said before, I had decided to leave the front legs bent and in modifying the hips I actually added at least a centimeter to the length of the femurs as well as moving their attachment points down from the iliac crest to the new sockets. The end result was an animal that was really tipped forward with really long upper legs giving it a gigantic stride. Before adding the plates and spikes, here is how it looked:
While I got down to work painting it with a coat of black primer, dark brown mixed with red for a second coat and a misting of medium gray with flat black washes and a little bit of medium brown dry brushing, I began to have misgivings about the way it looked. As I said before, I had decided to leave the front legs bent and in modifying the hips I actually added at least a centimeter to the length of the femurs as well as moving their attachment points down from the iliac crest to the new sockets. The end result was an animal that was really tipped forward with really long upper legs giving it a gigantic stride. Before adding the plates and spikes, here is how it looked:
No matter how I looked at it, it
seemed more like a skedaddling Scelidosaurus than the self-confident
Stegosaurus I was trying to make. My misgivings were confirmed
when friends viewing some preliminary shots commented on the length of
the stride and wondered if I had a reason for keeping the front legs
bent. The more I thought about it, then more I felt that I
should probably make some changes. Accuracy aside, there is
another agenda here. I am planning to re-build my original
Stegosaurus as a somewhat different stegosaurid. Most other
members of the family are always shown with bent front legs and are all
smaller than the North American Stegosaurus stenops on which this model
is based. They are all shorter, and bending the elbows will help
with the illusion of a smaller animal. I'm not sure when I will
get to that project, but at least I am thinking ahead.
As far as the front legs were concerned, I had a hard time finding good images of skeletons with them straightened rather than bent. There are plenty of pictures of life restorations in that configuration, but most museum skeleton displays don't seem to have been adjusted. This summer I had gone to a display at the San Diego Natural History Museum where a Stegosaurus skeleton from the American Museum in New York was on display. After taking a few pictures I was told that photography was verboten, but in reviewing my photos, I was delighted to find that I had gotten the shots I needed, and they showed the front legs in a vertical configuration! To be honest, I was not that impressed with the way the joints articulated in that mount, but I decided to go ahead and make the necessary changes. Clenching my teeth, I snapped the front legs off from the scapulas and used a wire cutter to do the same to the rear legs. Of course, this caused the spine to snap at the the lumbar-sacral junction, so I used that as an opportunity to insert a long steel pin for future stability. Next I used a razor saw to make the necessary angled cuts to separate each humerus from the ulna with its olecranon.
As far as the front legs were concerned, I had a hard time finding good images of skeletons with them straightened rather than bent. There are plenty of pictures of life restorations in that configuration, but most museum skeleton displays don't seem to have been adjusted. This summer I had gone to a display at the San Diego Natural History Museum where a Stegosaurus skeleton from the American Museum in New York was on display. After taking a few pictures I was told that photography was verboten, but in reviewing my photos, I was delighted to find that I had gotten the shots I needed, and they showed the front legs in a vertical configuration! To be honest, I was not that impressed with the way the joints articulated in that mount, but I decided to go ahead and make the necessary changes. Clenching my teeth, I snapped the front legs off from the scapulas and used a wire cutter to do the same to the rear legs. Of course, this caused the spine to snap at the the lumbar-sacral junction, so I used that as an opportunity to insert a long steel pin for future stability. Next I used a razor saw to make the necessary angled cuts to separate each humerus from the ulna with its olecranon.
After some putty and sanding, new
articulations were formed and reinforced with pins.
Old elbows New elbows
Old elbows New elbows
The femurs were easier to
fix. I chopped of the revised heads and made new ones with extra
sprue, leaving them around one and a half centimeters shorter, then
glued them back into the hips, using the base as a template for
location.
Each
of the feet has a pin that fits into the base, so
the whole thing can be removed. Some extra touch-up
on the paint was all that remained. As with any model, there are
definitely ways to improve this beyond what I already did, but at this
point there are no major issues eating at me. I may still add
some cervical ribs, but I will probably leave the legs alone unless
there is some future revelation that determines once and for all that
they are bent after all.
