Sunday, 10 December 2017

Labyrinthodont teeth

Finally, I'm getting some new content up on here!   Today's blog post is about palaeoart, though it's really more art than palaeo.  These are sculptural studies showing three cross sections of labyrinthodont teeth.






Labyrinthodonts were a group of carnivorous amphibians common during the late Palaeozoic and early Mesozoic, and their key distinctive feature was their teeth.  These things are fascinating.  What's happening here is that the enamel folds in on itself towards the center of the tooth, creating characteristic channels inside the tooth structure.

 It seems the teeth evolved this way because the infolded enamel made them stronger while the teeth were growing.

Thursday, 18 May 2017

Lamina cribrosa sculpture

I finished the lamina cribrosa sculpture ages ago, but didn't post about it until now because I wasn't sure if I liked it, or if I wanted to change the colours completely.  So I left it alone for ages, and now that I come back to it I think it's probably okay as it is.


The more I look at it, the more I see the eye of Sauron.  I'm okay with that, though.


I did want to do some interesting things with colours on this sculpture, because that's half the fun of sculpting something as seen through an electron microscope.  The microscope itself doesn't produce a coloured image, but it's common practice to add colours in post-production.  Strong colour contrasts (such as blue/orange, red/green, yellow/purple) are a popular choice, partly because they look cool and partly because they help viewers identify different parts of the image.

I've stuck to that convention and used magenta and chrome yellow on the lamina cribrosa, with Payne's grey on the surrounding membrane.  Here it is in close up:




Thursday, 12 January 2017

Using hemp fibers in anatomical sculpture

It’s always good to try new things.  This week I’ve been experimenting with using hemp fibers in sculpture.  I wanted something fibrous, and hemp string turned out to be ideal.

This is another episode in my long-running fascination with things that look abstract but aren’t (for another example, see here).  It’s the inside of a human eyeball, as seen under an electron microscope.  The round thing in the middle is the point at which the optic nerve enters the eye.  This is called the lamina cribrosa.  In reality it's about 4mm in diameter, and it's like a little sponge with nerve fibers growing through the holes.  The two large holes in the center allow a vein and an artery to enter the eye.  The lamina cribrosa is surrounded by a membrane.  Note that you cannot see the rod and cone cells, because they are underneath the membrane.  Human eyes are inside out; light has to pass through a membrane layer before it can be picked up by the rod and cone cells.


That's not an optical illusion, the whole thing is slightly concave.  It curves upward at the corners because it represents the back of an eye, as seen from the inside.


The brown parts are hemp fibers incorporated into the membrane around the lamina cribrosa, which is made from thin strips of paper rolled into small cylinders and glued together to mimic the structure of the real thing.



Lamina cribrosa, halfway through construction.


For reference, these are pictures of the real thing, as seen through an electron microscope.



Image found here.


Image found here.

You can see the tissue is very fibrous, and so I needed a fibrous sculpting material to represent it.  The hemp fiber works well and creates an interesting variety of textures.  When the sculpture is painted the hemp will be the same colour as the rest of the membrane, which will highlight the differences in texture.

Monday, 9 January 2017

Avalofractus

Happy New Year readers!  Following on from my haootia quadriformis sculpture, I've been sculpting some more Ediacaran life forms.  In this case, rangeomorphs.  These were fern-like organisms that lived on the sea bed 635-542 million years ago and were obviously very successful, because there were a lot of different species.  This one is called avalofractus



Finished sculpture showing three avalofractus specimens.


The interesting thing about rangeomorphs is that their body shape was fractally symmetrical.  Modern animals are usually bilaterally symmetrical, though some plants have fractal growth patterns.  Rangeomorphs, however, had a central column anchored to the sea bed with a round holdfast, with branches growing out on alternate sides of the column.  Each branch grew sub branches, and so on.  Every little branch or frond was a miniature version of the whole animal.


Beothukis mistakensis model og growth:
This diagram shows the rangeomorph's fractal growth pattern.  The image comes from this paper by Jennifer Hoyal Cuthill and Simon Conway Morris.

I think this is just so cool.  I say animal but in fact there's some debate as to exactly what they were, and whether they were related to modern animals at all, or whether they evolved completely separately.  Although they looked like ferns, they weren't a kind of plant.  Plants use photosynthesis, and rangeomorphs did not.  They lived at the bottom of the sea where there's no light, and probably used their fronds to absorb nutrients directly out of the water.  



These sculptures are much larger than life size.  In reality avalofractus was only about 5cm long.


As with the haootia sculpture I used a simple colour scheme where the background is painted indigo and the avalofractus figures are a lighter indigo.  Again, this is my conjecture based on the fact that there's no fossil evidence for animals with eyes at this time, and there was no light at the bottom of the sea where these things lived anyway, so why would they be colourful?  I could be wrong.  There are deep sea creatures today that are colourful, even though they live in a world without light.  However, I like the simple blue colouring.  It gives them a somewhat ghostly look against the dark background, which is appropriate for deep-sea animals.

Wednesday, 7 September 2016

Finished haootia quadriformis sculpture

The haootia quadriformis sculpture is finished.  To recap for the benefit of any readers who haven’t read my previous blog posts, haootia quadriformis is a small marine animal similar to (and likely related to) modern jellyfish, which lived 560 million years ago during the Ediacaran period.  

Ediacaran life forms are very interesting to me as a sculptor because they’re just so weird.  Haootia is actually one of the less strange ones, but it still makes for an interesting sculpture.




As I said yesterday I did retouch some of the paint.  I didn't change it very much though, just evened out the colours a bit.  

Here it is from the side.  You can see the haootia's body projecting slightly from the surface of the background, however you can't see the whole body.  Haootia had a little stalk and a disc shaped foot, which is not shown in this sculpture.





I decided against varnishing it, even with matte varnish, because any varnish would change the sculpture's texture and I like the texture as it is.  

Tuesday, 6 September 2016

Colouring the haootia sculpture

In yesterday's post I showed you my new haootia quadriformis sculpture.  Last night I got stuck in and painted it.





The big question here was what colour to make it.  Jellyfish are the closest things to haootia that still exist today, and they can sometimes be brightly coloured.  But what about an animal that lived 560 million years ago in the Ediacaran period?  Haootia didn’t have eyes as far as we can tell and neither did anything else around at the time; there’s no fossil evidence for eyes before the Cambrian.  Would Ediacaran life forms have evolved coloured skins when there was nothing that could see them?  Unfortunately we will probably never know, so this is one of those situations where an artist has to use their best judgement.  

I took the conservative approach and used very little colour, just white and indigo.






I may go back and re-touch some of the paint inside the haootia because it's not exactly my best work.  By the time I got to those parts of the sculpture it was late and I had a migraine.  I was determined to finish the job, but I wasn't really feeling it and it shows.  

I'll also give the sculpture a coat of matte or semi-gloss varnish.

Monday, 5 September 2016

Haootia quadriformis sculpture

Haootia quadriformis is a small polyp-type animal which lived around 560 million years ago, and is believed to be one of the first creatures to have muscle tissue.  I’ve wanted to do something with haootia ever since the discovery was published in 2014, but couldn’t work out exactly what I was going to do.

Finally I got the idea to make a small sculpture that emphasises the little animal’s symmetrical body plan.





This is haootia seen from above.  From the fossil evidence it appears to have been cup-shaped, with small tentacles branching off at each of its four corners, so that's what you see in the sculpture.  The sculpture is about life size, maybe slightly bigger.

The following pictures show the haootia fossil discovered in Newfoundland, along with an artist's reconstruction of what it probably looked like when it wasn't squashed flat, and a modern staurozoan (stalked jellyfish), which is possibly a distant relative of haootia and is a similar type of animal.



The two top images show the original haootia fossil from Newfoundland.  Bottom right is an artist's depiction of what it looked like in life, and bottom left is a staurozoan, a similar type of animal which is still around today.  Picture from The Economist.


I used these pictures to determine how my haootia sculpture should look.  I should point out we don't know exactly what haootia looked like inside.  The Newfoundland fossil doesn't show evidence of any clearly defined structures inside the animal, so I went with a very simple shape.  Modern polyps have a mouth and the body of the polyp forms a stomach cavity.  I assume haootia absorbed nutrients through the walls of its body cavity, but the fossil shows no sign of a mouth.