Critter of the Week: Plesiosaurus

Meet Nessie.  This curious undersea critter is always looking for an opportunity to nab a treat.  You’ll never see her coming!  Her favorite game is hide-&-seek. 🙂



Look at that smile, I think she wants you to chase her!

Nessie loves a good game of hide & seek.  She’ll find a good spot in the sand, bury herself with those powerful flippers, and wait until an unsuspecting fish or squid comes by…

Snap!  Up comes her head, and the squid is lunch before it knows what’s happening.

Other times Nessie likes to be the seeker instead, and come up to a school of squid.  It’s hard to tell exactly how close she is…the squid are easily tricked into thinking that she’s further away than she really is, so that long neck of hers can dart in for a quick bite.

Her neck is actually quite stiff, more like a fishing pole for extra leverage than the swan-like curviness you usually see on the Loch Ness monster.  But Nessie can put that leverage to good use.

There were more squid and squid-relatives than fish in Jurassic oceans, and one of those relatives are ammonites.  If you’ve never heard of an ammonite (am-oh-night) before, then you can think of them as squid with snail shells.

The big difference (aside from not being related to snails)… Snails have their entire bodies inside their shells, with all their delicate organs near the center of the spiral.


Ammonites don’t live in the whole shell.  Instead, the shell is divided into chambers, and the ammonite only lives in the chamber nearest the “door”.  The other chambers may be used for sinking and rising in the water quickly, rather like a submarine.

Now ammonites have really tough shells, and there are billions of these things swimming around (even more than squid), but how to eat them?  Nessie’s jaws are too delicate to chomp through a tough shell, and though she can just swallow whole a little ammonite that’s 2 inches in diameter (if she can catch it!), how could she tackle some of the bigger ones?  Some could grow 10 feet across!  Once they squeeze into their shell and close the “door”, there’s no way Nessie could get at it.

Here’s where a stiff, very muscular, long neck could come in handy.

Sneak up on an ammonite just fast enough to grab hold of a tentacle before it can pull itself in its shell.  Then roll and twist.  Tentacle breaks off and Nessie gets some nutritious and delicious calamari.  Ammonite moves on with its day and regrows the lost tentacle. 🙂

Now these are all possibilities on how Nessie could’ve used that long neck.  If you want to read more on how this could work, check out Antediluvian Salad, an amazing blog written by the incredibly knowledgeable Duane Nash.



Making progress…

The first thing I did this week was make a little chart to print out, with Steggy and all the people the size I needed them. Steggy is a domesticated breed of Stegosaurus stenops, a smaller species of stegosaurus, so she’s not as large as some of her wild cousins. 🙂 The vertical bar represents 2 meters, or roughly 6 feet. I know it doesn’t convert perfectly, but I’m not going for perfect. They’re accurate enough for their purpose. 🙂

Daddy is bent over and holding onto Baby’s hand, by the way, if he straightened up he’d be exactly as tall as the 6″ bar. 🙂

I didn’t quite realize how small these guys would be until I put my hand next to them.

Since you wanted to know how I figured out scale (and because I want to have a nice convenient place to look back if I need it again), here is the formula I used to figure out how big to make Steggy. And from there, the people…

1. Take the size of the dinosaur toy. This can be in inches or centimeters. For our example, we will use the original Carnegie Dimetrodon, which is 3 inches long, or 7.6 cm.
2. Look up the actual size of the animal. Dimetrodon was 3 meters, or 11 feet.
3. If you’re using feet, multiple the size by 12 to get it into inches (ex. 11×12=132 inches), or by 100 to get centimeters (3×100=300 cm).
4. Divide the number you calculated in 3 by the size of the toy itself (in the same scale).
ex. 132/3=44
Therefore, the figure is 1/44 scale!

The formula is not mine. You can check it out in more detail here:

Now to get to work! 😀

While I’m waiting for the supplies I ordered to come in, I’ve been working on Steggy. First up, a proper armature! Hehe, I didn’t do this with my last clay-modeling adventure with Douglas, so it’s nice to have a solid skeleton for little Steggy.

I must admit, with the new proportions calculated by Scott Hartman (based on the Sophie specimen), this doesn’t look much like a stegosaurus yet.

I kept lining up my armature to the skeletal diagram to make sure everything was lined up right. The curve of the neck and tail make it look like it doesn’t fit, but it does! 🙂

The next step was putting a base layer of clay on the armature. To add a bit of basic bulk, and make it easier to build layers of clay. Also, Steggy needed a head, because my daughter said so. 😀

I only used enough clay to cover the aluminum foil and wire. I baked this, and now I’m adding layers of muscle. It’s taking a bit longer than I hoped, but I think with practice I’ll get faster, just like I’ve improved with drawing over the past couple of years. 🙂


I “traced” all the little plates and spikes with clay. Right now all the spikes are just tiny cones, but I hope to give them their true shape when I attach them to Steggy’s tail. The two spikes closer to the last plates have more of a slightly curved, half-moon cross-section, according to the description of the Sophie specimen.

So many tiny plates and spikes! Seriously, most of these are smaller than my pinky fingernail. 😀


Here are the two different sides to my little scale stamp I made. One has larger scales, and the other side has tiny blips to just suggest scales. Stegosaurus had larger, oval shaped osteoderms surrounded by tiny, 3mm “pave stone” scales. At the scale I’m making my little model, you’d only really see the larger osteoderms. I’m waffling between scaly skin wrinkles like a komodo dragon, or thicker skin like the Mexican Beaded Lizard.

I’ll show some examples of what I mean next week. I should be done by then. 😀

In the meantime, here’s some more progress I have so far. 🙂 Starting to look a little more like Stegosaurus! Steggy needs feet of course, as my daughter frequently reminds me (she’s really loved “helping” me make my “tegotawrus”). Her spindly legs don’t have the muscle power to hold her up either, but she’s getting there. And I’ve started experimenting a little with how the skin on her neck will wrinkle up. She will definitely not have elephantine wrinkles. Thick, scaly hide behaves differently from carunkled skin. It’s a bit of a pet peeeve of mine to see so many dinosaurs with elephant-skin wrinkles.

That ridge along her spine will probably not be there when I’m done with her either. The vertebrae provide anchor points for a thick strip of muscle on either side. I’ll be embedding her plates along this soft ridge, then layering tissue on each side to hold the plates in place. It’s been suggested that the plates could’ve been embedded in tissue in this way, and that enough layers of soft tissue between the plates and the spine could’ve allowed for greater flexibility than is usually thought for Stegosaurus.

I think I got a bit rambly this time…I’m partly documenting my process so that I can repeat it if it works how I hope it does (and learn from mistakes if it doesn’t). But I hope you find it interesting, or at least informative. 🙂

You can look forward to seeing more rambling like this next week! 😀


Coming Next Week…

This flyer will dive high and low for a fishy treat.

Share your guess in the comments! He’ll be one of the critters over on the critter page. 🙂

4 thoughts on “Critter of the Week: Plesiosaurus

  1. Ooh, interesting! At first I thought that you would start off with the clay and wire only, but using aluminum foil as a base makes more sense. 🙂 I never would’ve thought that calculating the scale would be so technical, either! How do you plan on making the diorama for Nessie and the other swimmers (or the flyers)? Also, will you be adding any plants to Steggy’s diorama?


    1. Hi Brownie! It’s good to see you here. 🙂

      There are several reasons for including aluminum foil in the armature. 🙂

      – it saves on precious (and sometimes expensive) clay
      – it makes the model lighter
      – it ensures the first layer of clay is relatively even in thickness, which makes it bake more evenly and easily.

      As far as how I’ll be making the other dioramas…I haven’t thought that far ahead yet 😛 I’ll figure something out once I get to them 😀

      And yes, I do plan on adding a few scraggly plants to Steggy’s diorama. Just enough to suggest how they cast shadows. 🙂 Not 100% sure how, but I think I can find some scraggy bits around here to get the idea across 🙂


  2. How did I miss this! I’m so sorry for the delayed reply!

    Nessie’s love for hide and seek (and her name) is my little inside joke about the Loch Ness monster in Scotland. Some speculate that original stories of the creature might have been inspired by a remnant plesiosaur that survived the extinction. Since “Nessie” at Loch Ness is so hard to find, she must be pretty good at hide and seek 😉 .

    I thought the diorama would be bigger too! At least until I fully realized how small my little models are, and then I got the picture frame that’ll be the base for my diorama…much smaller than I imagined. That’s ok though, since the important thing is the light, and seeing how things fit together in three dimensional space. 🙂 I’m glad you like my little Steggy. She’s getting a few more squishy layers at the moment, and I’m starting on details. Hopefully I’ll be done by Wednesday! 😀

    Halloween was fun. 🙂 My oldest is really into Superman now, so he was super excited to get his costume on! It had a built in muscle suit, and little sister was most impressed by his “muscles”. 😀 She dressed up all pretty in a princess costume. Baby brother liked the costumes the other two had, but was much more hesitant to get into his own. But I finally convinced him to put on his little chicken costume for a sweet treat. 🙂 We didn’t do any trick-or-treating, but there was a Halloween festival in town with all sorts of fun games and inflated bounce-houses and slides, so the kids had a blast. 😀 A fun and safe way to have a good time on Halloween with little kids in tow!

    Yep! It’ll be super easy to get Ron on board. Just toss a few fish in there and he’ll dive in. 🙂


  3. Why does Nessie like hide and seek? Is that her favorite game? Or is there something much more sinister behind it? Is Nessie hiding from a creature? Dun dun dunnnnnn! It’s past halloween and still making jokes 😀 I thought the diorama is going be big,but it turned out to be small.Progress looking good so far,i’ve been liking that stegosaurus sculpt! As i am typing this,i am watching Lights Out,and just a question,how did your family spend Halloween? Mine was rather boring 😦 Ron is excited for the train!


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