Hexapod evolution in a twist

Just a short post this time, as I am busy painting. The painting in question involves the early evolution of hexapods, something also discussed in a post titled 'The lateral fin theory and mackerel mode'.  

Click to enlarge; copyright Gert van Dijk

Above you see the specimen of 'Fishes II' that was shown in the previous post. It was digitally sculpted and painted in Sculptris. Such sculpts help define the perspective of the undulating fins. Once you have such a shape in your computer, you can go two ways: the first is to  perfect digital sculpting, which at present probably means mastering ZBrush. That road does result in a 2D image, taken as a snapshot of the model, but do do that the models need to be sculpted with much more finesse that the rough ones I produce. Readers of this blog will know the work of Marc Boulay, who does all this at the expert level.

But I chose to stick with regular figurative painting, because there is something about a painterly look that I like. It is not that easy to define 'figurative painting' in such a way that it excludedes digital sculpting. Perhaps it is creating the illusion of a three-dimensional object by placing colours on a two-dimensional surface. This includes digital painting as well as classical painting using oils or water colours or any such technique (I sometimes encounter a resistance against digital paintings in art circles, which must mean they see it something else than it is: just another technique).

In this process, 3D sculpt programs are aids to get the perspective or the lighting right. As with any technique they have their own unique problems. People will accept any perspective on a photograph or computer rendering, but not on a drawing (see here for an explanation).

Click to enlarge; copyright Gert van Dijk

Anyway, I try to produce a painterly effect. The two images above show two versions of the head of the Fishes II species Vexilloscissus. The left one was based on the 3D sculpt. I thought the painting was finished, and suddenly realised that there was no way that the six protojaws seen here could evolve into the typical four jaws of the basic terrestrial hexapod Bauplan. That design involves upper and lower jaws with two rows of teeth each, and two lateral jaws with one row each.  While sculpting I had forgotten that, so I had rotated the ensemble of six jaws incorrectly, with jaws in the midline in the upper and lower positions, and no jaw in the lateral positions. In world building it is hard to keep tracks of all the details, or at least that is my excuse for the mistake.  

So I had to erase the jaws and paint them again in the correct position. The result is at the right. It's a  pity really, as I rather preferred the left one. Oh well, never mind...      

Ballonts in Gas Giants ('Ballonts V')

More ballonts? Well, yes: I had previously explored whether it is possible to produce a fairly small life form floating around using the lighter-than-air mechanism, but there were some loose ends left. As the last one was posted in 2011, it may be wise to recapitulate a bit (or work your way up from here, through here, to this one).

Click to enlarge; copyright Gert van Dijk

The image above show a scene on Earth on sea level at about 20 degrees Centigrade. A default local sophont (let's call him 'Julius') holds a stick indicating two meters. There is also a balloon with a radius of 62.03 cm. Why 62 cm? Because that yields a sphere with a volume of exactly one cubic meter (m^3). The skin is made of a 0.1 mm thick mylar-like material with a mass of 0.5802 kg. The balloon is filled with the lightest possible gas, hydrogen. Hydrogen has a density of about 0.0899 kg/m^3 at 20 degrees, while the air has a density of 1.2019 kg/m^3. So, the 1 m^3 balloon has 0.0899 kg of hydrogen in it, while the corresponding volume of air has a mass of 1.2019 kg. The balloon can therefore lift 1.2019-0.0899 = 1.1120 kg (that is the part needed to understand how balloons work). As the skin masses 0.5802 kg, that leaves 1.1120-0.5802 = 0.5318 kg to build a nice body out of. That is not a nice big body at all; given a body density of 1.1 kg/m^3, which is like our bodies a bit heavier than water, we can hang a spherical body with a radius of just 4.9 cm under our balloon, and the ensemble will then just float. Of course, a real animal would have tentacles and limbs and mouthpieces etc.

As said, I wanted ballonts with a body mass of, say, 10 kg but with only a moderately sized sac. As the example above shows that does not work on Earth. The hydrogen inside the balloon cannot be made lighter, but we can alter the atmosphere outside it; this is speculative biology after all. There are two ways of doing so: the first is to stuff the atmosphere with very heavy gases such as argon, but such elements are quite rare in the universe. The other is to add mass by increasing pressure, as that will squeeze more mass in the same volume. So, let's explore gas giants, where high pressures are easily found.

Click to enlarge; Source: Brian Vanderwende University Colorado

The pictures above show information about 'our' gas giants: the composition of the atmosphere, the temperature and the pressure. Not surprisingly, atmospheric pressure increases the deeper you descend into the atmosphere. For our first try, we should perhaps be a bit conservative and stay with biology in fluid water. A temperature of 20 degree centigrade should not upset Julius; it is the same as 293 degrees Kelvin. For Jupiter, the 293 Kelvin zone results in an atmospheric pressure of some 9-10 times that of Earth, which sounds like a decent start. Instead of jumping in directly, it may be easier to take it in stages, building on the Earth model shown above.

Click to enlarge; copyright Gert van Dijk

The image above shows the first step: Earth's atmosphere is changed to a Jovian one at one atmosphere and 20 degrees centigrade. Internet sources show that the Jovian atmosphere consists of about 86% hydrogen, 14% helium and a smattering of other compounds. Based on the densities of hydrogen (0.0899 kg/m^3) and helium (0.1664 kg/m^3) the density of a 86:14 hydrogen/helium mixture should be 0.1006 kg/m^3. Oops! That is only very slightly denser than pure hydrogen, which we need to fill the ballont with! If you thought Earth air was a bad medium for ballonts, think again. So what are the effects? Well, the liftable mass is 0.1006-0.0899= 0.0107 kg. Remember that the skin had a mass of 0.5802 kg? There's nothing left for a body, so this balloon is not getting off the ground at all.

Click to enlarge; copyright Gert van Dijk

We were aiming for high pressures, so let's increase the pressure to 10 atmospheres. The mass in the balloon will be 10 times higher, and so will the mass of the equivalent volume of air. So the liftable mass also becomes 10 times larger: 10 x 0.0107= 0.107 g. That's still nowhere near the mass of the skin, so this balloon isn't going up either.

Click to enlarge; copyright Gert van Dijk

Let's leave Jupiter and find a ballont-friendlier place. Uranus and Neptune have atmospheric pressures about 50 times Earth's at the 293 Kelvin range. That's better, and apparently the Uranian atmosphere is heavier, with 2.3% methane thrown in. I make the density of its mixture to be 0.1148 kg/m^3 at 1 atmosphere and at 20 degrees C. So, the 1 m^3 balloon can lift 0.1148-0.0899 =0.0249 kg. That is not good enough, but at 50 atmospheres the liftable mass is 50 times that, or 1.2450 kg. Subtracting the skin leaves 0.6648 kg. Finally, a floating balloon! Hurrah!

Or perhaps not 'hurrah', as that is only a tiny bit more than what we had on Earth to start with... Let's go up to 200 atmospheres in Uranus: the liftable mass, skin already subtracted, would be 4.4 kg, and at 500 atmospheres it would be 11.9 kg. Finally we have what we wanted!

Well, not really; these values are not yet adapted for the lower temperature. Julius is left behind, as we need a wholly new biochemistry. The atmosphere is now also so soupy that you would not want to think about the wind or moving in it. Adding even more problems, there is another potential disaster lurking in these gas giants: gravity. The gravity constant for Uranus is nice at 8.85 m.s^-2, a bit less than Earth's at 9.8 m.s^-2. But Jupiter has a value of over 25, so if you thought you could get away with a nice fragile ballont there, waving its slight tendrils through the air and looping in prey with slender tentacles, think again: the animal would need the sturdy limbs befitting a 2.5G environment.

It really does seem as if the universe is trying to sabotage ballonts, doesn't it? Gas giants do have high atmospheric pressures, but their beneficial effects are counteracted by the fact that the atmospheres consist of very light elements. It seems that the only way to get a viable (pun intended) ballont on a Jovian planet is to make the ballont extremely large. But that is where we started... I am beginning to think that there may not be any appreciable advantage in locating ballonts in gas giants, even though science fiction is full of them. They do about as poorly there as they do on terrestrial planets, meaning they can in fact work, but they have to be big, very big. Perhaps gas giants have other advantages for ballonts: there's certainly a lot of atmosphere to play with in them.

Ca I still claim that ballonts are so common in gas giants that they are boring? Yes, but they will be big, as usual; perhaps that's what makes them boring. The best way out for small ballonts seems to be offered by terrrestrial planets with heavy gases and high pressures: Venusian analogues? Perhaps there will be a 'Ballonts VI', one day.   

Evolving another aggie

Click to enlarge; copyright Gert van Dijk

What you see here is a sketch of the 'aggie', the favourite prey of the marblebill. The pages detailing the marblebill in The Book have this to say regarding the aggie:

"The marblebill’s favourite prey is the ‘Aggie’ (Agitator augur), a tree-dwelling fructivore. Once caught, the victim’s feeble attempts at defence have little chance of success against the marblebill’s armoured chest and abdomen. There is little time for resistance anyway, as marblebills usually disarm their victims quickly by snapping its cervical medullae."  

 "A troop of Aggies, admittedly not the brightest of beasts, may suddenly see a branch swaying and a baignac falling. Only when they hear the marblebill’s triumphant howl does it dawn upon them that one of their comrades had just now been sitting on that branch and been munching that baignac."

That's all that is known in the entire universe regarding the aggie. I have started sketching them several times, but was never too happy with the result. The sketch you see here is not the definitive aggie either. This particular one is a brachiator, just like the marblebill. The degree of adaptation of the marblebill to its arboreal brachiating life style suggests that its environment has been around for quite a while. If so, other species could be equally well adapted to an arboreal way of life. That does not necessarily imply brachiation (see here and here); the animal could be a jumper, a climber, or even a glider. But this one is a hexapod brachiator.

Click to enlarge; copyright Gert van Dijk

In previous versions I toyed with the idea of using the second pair of legs as the main. In fact, here is an old very quick and dirty sketch showing that approach (Brynn Metheny also did one once, the 'pygmy esorifleu', which I discussed previously). In the 'Mark I' the body is suspended from the middle limbs, and the front and aft ends hang down. It must have evolved from basic hexapod stock, and it is hard to imagine an ancestral species with six more or less equally-sized legs preferring to grasp branches with its second rather than its first pair of limbs. You can see the 'Mark II' next to it. That sketch was ancestral to the marblebill's design, and they still swing from their front limbs.

Click to enlarge; copyright Gert van Dijk

Still, there may be a way to evolve a brachiator with 'middle limb suspension'; take a typical Furahan neocarnivore, one of those animals exhibiting centaurism. As you may remember their first pair of legs are not used for locomotion but to catch prey. If such an animal started climbing trees, it might keep its weapons intact, and adapt its second and third pair of legs for locomotion among the branches. Its offspring could become either become jumpers of climbers, using four more or less equal limbs, but they could also turn into brachiators. If so, they would swing from their middle limbs and use their front legs as weapons. In my mind, I  see the hexapod evolutionary tree sprouting a new branch even while I am writing this...
Then again, a neocarnivore taking to the trees might use its spears or clubs to hook a branch. Being at the front of the body they are well placed to do so. If these limbs then become brachiating arms they would resume a locomotor function again; I see another evolutionary branch exploding into view with an almost audible 'whoomph'. By the way, that latter branch is also the first official example of 'decentaurism', or the reversal of nonlocomotor limb use to a secondary locomotor purpose.

Anyway, back to the aggie. Have a look at some of its features.

• It sits upright, which may make sense for a brachiator: its body is held vertical while brachiating, and it might easily keep doing so at rest.
• Its limbs are attached to the body with joints that allow three axes of rotation. The brachiating arms are attached to the body through a short bone that ends at the 'shoulder'. Unlike Earth primates, the shoulder girdle is attached through bones to the axial body skeleton rather than through muscles only, but the animal still needs thick muscles to control the position of the body with regard to the arm. The unfortunate result is that the attachment looks much like a primate shoulder girdle; parallel evolution or a limit of my imagination?
• You might just make out the ancestral hexapod toe branching pattern (more about that here). 
• This particular aggie version has a pot belly. While sketching it I had forgotten about it being a fructivore with a preference for baignacs (remind me to show you a baignac one of these days). Fruits usually offer high quality food, so animals does not need many of them. While sketching I had low-grade food in mind, say fibrous leaves, and such food requires a lot of processing and a sizable gut. Specialising on low-grade food has the advantage that there will not be much competition, but the end point might be a slow animal that is not at all energetic: something like an Earth sloth. While sloths are preyed upon by harpy eagles, the dense parts of the forests are probably closed to eagles. But introduce the marblebill, and anything as slow as a sloth has a problem. So, the aggie cannot be too slow. It should probably lose its potbelly and resume a high-energy fruit diet. Of course, it should perhaps be better able to defend itself, or use its social skills, or perhaps...

...never mind; thinking about the aggie has once more led to interesting predators rather than their prey. One of these days I will design the definitive aggie; this is not yet it.

Fiddling with photosynthesis (Alien Plants IV)

'Alien Plants IV'? Where are the other 'alien plant' posts? Well, 'Alien plants I' and 'II' were published a long time ago, and 'Alien Plants III' was not labelled as such: that would be the post 'The black, black grass of home...' posted one year ago. That one was more serious than the first two, and  dealt with the colour of plants on Earth. To be succinct: green does not equal photosynthesis.

Click to enlarge. Copyright 2007 University of Chicago. From: Nature's palette by David Lee

As can be seen from the absorption spectrum of chlorophyll above, photosynthesis does not use the green portion of the spectrum, so that portion gets reflected for us to see. In doing so plants ignore much energy potentially available to them, as green is right in the part of the spectrum where the sun emits a lot of light. You might think that photosynthesis would evolve to make the most of the light falling on it, and, if so, you would predict that Earth plants should be purple (see the 'black grass'  post for speculations why some bacteria are purple but plants are not).

Some people wonder whether we can predict the colour of plants on a planet by looking at the spectrum of its sun. Earth's example definitely suggests that we cannot, so I personally see no problems with filling hypothetical planets with plants of just about any colour; well, as long as the absorbed colour is present in that sun's spectrum, of course. A perfect photosynthesis process would be able to use light of every frequency equally well, with the effect that such plants would be grey or black.

After writing the 'black grass' post I returned to the question why it is difficult to come up with alien-looking plants. Intuition suggested that there would be only so much you could do with plant shapes: flat leaves fixed to the ends of a branching structure seem so sensible that they are probably universal, so plants everywhere would look similar. Perhaps so, but intuition is not a reliable predictor in science, so some old-fashioned studying was called for. I recommend 'The Life of a Leaf' by Steven Vogel, who also wrote a fine book on biomechanics.

The fun part will be designing new plant shapes, if possible, but before we get to that there is some work to do, I am afraid. This post starts with photosynthesis on Earth, to find out if it can be tweaked to produce plants with a high degree of 'alienosity'.

Click to enlarge; Based on Long SP et al. Can improvement in photosynthesis increase crop yields? Plant, cell , and environment 2006; 29: 315-330

1. Efficiency of photosynthesis
The job of photosynthesis is to take water, CO2 and light, and turn out carbohydrates to use as energy sources and building materials, with O2 as a leftover waste product. Although the total energy capture by photosynthesis outranks human power consumption by far, photosynthesis is less efficient than the photovoltaic process used in solar panels. Photosynthesis is surprisingly inefficient.  The image above is based on analyses done by scientists looking for ways to improve crop yield. The 'black grass' post explained that only a portion of sunlight is used for photosynthesis, and the papers show that portion to be about half of the available energy. The graph above states the efficiency of each step, which is which fraction of energy gets passed on to the next step. The efficiency of the first step is 0.5: of 100% light to start with, 50% is left. That's a big loss. 
   The efficiency of the next step is 0.9. In terms of the original amount of light 45% goes on to the next step. And so it goes on, multiplying all the efficiency factors in turn, step by step, until only about 5% of the original energy is left at the end. As I said, not impressive at all. I should add that this holds for the so-called C3 photosynthesis type. The C4 type does better, managing to end up at 6 to 6.5%.  That does not seem like a big improvement, but it is still up to 30% better than C3 photosynthesis.      

One biochemical step deserves additional mention: 'photorespiration'. The reactions that take in H2O, CO2 and light to turn them into sugars and O2 are not exactly simple; an important enzyme capturing CO2 is ribulose-1,5-bisphosphate carboxylase oxygenase (no wonder that it is called 'Rubisco'). Rubisco deserves to be known, if only because it is probably the most common protein on Earth. Its job is to speed up the reaction binding CO2 that ultimately ends in O2. Oddly, Rubisco binds quite readily with O2, driving a process in the wrong direction! This backwards process is called 'photorespiration' and has puzzled biologists a lot. Its presence suggested that it might have some use, but apparently plants do quite well in artificial atmospheres without any O2 at all, so photorespiration seems to be a gigantic and puzzling waste.

2. Bright light: photosynthesis saturation
As if the above series of limitations is not enough, there is another one: photosynthesis saturates. Photosynthesis normally increases with the level of light but only up to a point. If light intensity increases beyond that point, photosynthesis cannot increase with it (it may apparently even decrease to protect the plant). Whether this is an important limitation depends on where you are: to catching the maximum amount of light to reach the Earth's surface, you will have to stand at the equator, at noon, on a clear day. The C3 type of photosynthesis can only use about a quarter of the light there! If you were to add that step to the image above, the scheme would start with a giant loss of 75% right at the start. Seen in that light (pun intended) the overall efficiency of 5% becomes an even less impressive 1.25%.

Then again, it is a bit unfair to set light at noon in the tropics on a cloudless day as the standard. Living at higher latitudes, clouds and shadows from mountains or leaves will limit the amount of light that reaches a plant, so in many cases the saturation point will never be reached. That is fine for those plants, but the tropics are still there, and photosynthesis could do a lot more for tropical plants  if their saturation point would lie at a higher intensity.

3. Shadows: the photosynthesis compensation point      
Plant cells burn molecules with the help of oxygen to free stored energy and use that for their metabolic needs, exactly like animal cells. This process is called cellular respiration and does the opposite of photosynthesis. As the amount of light decreases, photosynthesis will be less effective and produce less oxygen, while cellular respiration keeps using it a stable rate. At some shadowy light intensity the two processes are matched: the compensation point. When light levels drop beyond that point, plants become net users of oxygen and energy instead of producers. Plants can survive that state and in fact do so every night, but over time there must be a net profit. There are many places, such as the floor of dense forests, where it permanently too dark for photosynthesis to work.

"It's photosynthesis, Jim, but not photosynthesis as we know it". 
With all this in mind there seems to be ample opportunity to tinker with the process and design an alien photosynthesis. Mind you, photosynthesis could well be even less efficient on an alien planet than on Earth, and that possibility should not be dismissed out of hand. World builders have a strong tendency to design super-organisms, better than what Earth has to offer, but that is not very realistic. For once I will follow the flow and aim to improve on Earth's state of affairs. The following list concerns my suggestions how to improve on off-the-shelf photosynthesis:

Alien photosynthetic to-do list
- Have your photosynthesis process use a larger portion of the light falling on it
- Increase its affinity for CO2 (abolish photorespiration!) and improve reaction speed 
- Increase its saturation point so it can use intense light
- Lower the compensation point so it can work with less light.    

This 'to-do list' assumes that there are numerous biochemical pathways that can take in CO2, H2O and light and produce carbohydrates. Such processes may be centred on completely different pigments, sensitive to other wavelengths.

Click to enlarge; copyright University of Chicago. From: Nature's palette by David Lee

The illustration above has nothing to do with photosynthesis itself, but illustrates that there are many pigments in vision that are sensitive to varying wavelengths and to varying ranges of wavelengths. The pigment of the nectar-varying bat is interesting in that it is sensitive to a very broad range of light with a broad peak in the green area. A pigment like that, used for photosynthesis, would result in plants using light best where there is most of it, without throwing the rest away. Such plants would probably be a boring dark purplish grey.   

You may well ask whether all this biochemical tinkering will make plants look different. If they still look like Earth plants but grow faster the exercise loses much of its appeal, doesn't it? I think they would look different: if leaves can use all light falling on them, that will have consequences for any leaves underneath; simple blobs or needles might replace complex leaves; the ability to have fewer leaves might induce trees to grow higher; plants might continue to grow through winter, etc., etc.

Click to enlarge; by Ghedoghedo

Of course, apart from biochemistry different biomechanical design principles will also result in differently looking plants. To see whether that approach yields interesting choices, we may need to travel back to the Silurian and Devonian and have a look at designs principles that came into being when land plants first struggled against gravity. Changing designs and changing plant biochemistry ought to result in enough 'alienosity' to please anyone. We'll see...

"All yesterdays" by Conway, Kosemen and Naish

This post departs a bit from my self-imposed limit of life on other planets. That was not a strict limitation anyway, as I have also written about future evolution. But both are easily classified as 'speculative biology', and the subject of this post, the reconstruction of extinct animals, is not usually regarded as such. Reconstruction of extinct animals feature in almost any book on the history of life, and there are even some books devoted completely to the imagery of extinct life forms. This specialised form of nature illustration has even acquired its own name: palaeoart. If you would like to see examples of recent -mostly- excellent art, consider this book. It leans heavily towards the current photorealistic style, whereas I personally find a painterly style much more evocative. If you are interested in the early history of palaeoart, I recommend this one ( I think it was the first to coin the term 'deep time'). Sadly, there is no name yet for the 'art of depicting speculative life forms on planets other than Earth', so perhaps one should be invented, even though the number of such books is sadly low. Possible contenders are 'astrobioart' or 'exobioart', not to be confused it with 'biofuturart' (the last one definitely needs to be improved).

The reason to pick out one particular palaeoart book is that this one stresses the speculative aspect of palaeoart, and shows that palaeoart is in fact fairly close to speculative biology. The book is written and illustrated by Darren Naish (from Tetrapod Zoology), Mehmet Kosemen (from Snaiad), and John Conway, a palaeoartist with a refreshingly original style (and a painterly one at that!). The three of them should be able to come up with something very original and they did. The book can be obtained in digital as well as a printed form. The book appeared in 2012, so this is not exactly a quick review. I do not care that much; with food the 'slow food' movement has things to say about eating, and many other things deserve the 'slow' treatment as well; some things are worth being savoured. 

The introductory text of 'All Yesterdays' discusses how palaeoart should be based on a thorough understanding of animal anatomy, but is limited nevertheless because so much of an animal's appearance is determined by its integument. As you know that can range from smooth and shiny through dry and scaly to shape-distorting feathers and pelts for Earth tetrapods. The authors then proceed to play with that idea in two ways, and those are what make the book interesting.

Click to enlarge; copyright John Conway

In the first part of the book, the authors take on Mesozoic animals and add a twist to conventional 'wisdom' of animal reconstructions. They add fatty humps to animals with large vertebral spines, where convention simply stretches a sail between the spines. They seem to have a particular dislike of the 'skinny' way of reconstructing animals, in which the skin is stretched tautly over an animal's skeleton. I agree with them that this style has been overdone. I suppose the underlying reasons to stick to skinny reconstructions for dinosaurs are lingering ideas about them being 'reptiles', and perhaps by a wish to conserve weight. Well, here you will find fat dinosaurs, with stumpy legs emerging from mounds of meat. The image above shows a rather rotund triceratops, which besides being less then athletic also has a range of spikes protruding from its hide.

Click to enlarge; copyright John Conway

The authors also play around with animal behaviour,  a field where reconstruction is nearly entirely  guesswork. Many artists paint Mesozoic landscapes with more animals than there are people in a city park on a sunny Sunday; Here, you find a lone animal on a hillside, with not even one single rampaging predator coming toward it full throttle. There are also plesiosaurs displaying who can lift its neck the highest out of the water; a very nice idea. The image above shows the cover of the book, showing protoceratops in a tree. In a tree? Well, yes. After all, you would not guess that goats could climb trees, but they can. The reasoning here is largely that they have climbed the tree because they could...  

The second part of the book is the truly original part. Here the authors take remnants of present day Earth animals and have some palaeoartists of an undetermined species in the far future have a go at reconstructions.

Click to enlarge: Copyright John Conway

The above is a cat... Very well, a cat whose skull was apparently preserved, but the palaeontologists could only guess at everything else. They came up with this fictional scaly and skinny hide, without cheeks or fur. I like this concept very much, and am tempted to find images of animal skulls and have a go at such fake restorations myself.

Click to enlarge; Copyright CM Kosemen

And this? Well, you are probably familiar with the extinct amphibian whose remains where first taken for those of a human drowned in the biblical great flood. In fairness, that particular mistake was made in 1726, well before palaeontology was underway, and before Linnaeus introduced his biological classification. The animal was later formally classified and named after its inventor, Johann Scheuchzer: it is now Andrias scheuchzeri. In 'All tomorrows', Mehmet Kosemen produced the image of a salamander man shown above, as an example of mistaken identity. The authors label it 'Homo diluvii', the 'man of the deluge'. Spelled with a capital 'H' the name looks like it is an official zoological name. So far I had always seen it referred to as 'homo diluvii testis'. The literal translation of that phrase is 'man, of the flood a witness' (the Romans were not at all particular about word order). That suggests that we are just dealing with a description in the scientific language of the time, not with a formal scientific binomen. I tried to find the scanned book on the internet to check the source but failed. It matters little; this is a great 'Salamander Man'!

All in all, this is an amusing book that makes you think. Mind you, I am not one of those people who think that 'amusing' has a belittling connotation. The combination of amusing and thought-provoking should appeal to everyone interested in speculative biology. The book provides an eye-opener in showing how much of palaeoart, an as yet more 'respected' genre than astrobioart, is full of speculation. In many cases we have become so accustomed to ways of portraying dinosaurs that it has become difficult to look at the reconstructions anew. It is very likely that speculative biology is equally full of such 'familiar faces', and it may be equally difficult to forget them. Still, that may be necessary to take a fresh look. Now, where is that large completely empty sheet of sketching paper?  

Spidrids and rusps: works in progress

The main Furaha site hasn't seen any significant change for quite some time now, which makes me feel a bit irresponsible. I have devoted the time I spend on this project wholly on the blog and on new paintings. As for the site,  I will get around to a complete 'redecoration' one of these days, and the blog is what you are reading right now, so there.

I am keeping the new paintings for the book but can show you bits of works in progress now and then, both of paintings and of blog material. In this post I will show progress on two themes, not that odd as I usually work on several themes at once (a major interest at present is working out which aspects of plants can be tweaked on other worlds, and what the results would look like; that is progressing nicely).

Copyright Gert van Dijk

I have discussed spidrids here several times, the last time here. That post showed them walking on uneven terrain in a variety of gaits. Those animations, done in Matlab showed how an animal with radial symmetry changed direction without turning. Although the animations showed that well, a proper 3D animation would be better. I am not aiming to achieve the quality of Avatar or Walking with Dinosaurs, but getting to a point in that general direction would be nice. The challenge then was to translate sets of coordinates of one system (matlab) into rotation and translation values for objects in a completely different format (Vue), and then controlling Vue to make an animation one frame at a time (Python). I won't bother you with the details. As you can see above, I am now at the stage where I can control the legs and have them end up on the right orientation and position. It really looks much better at a larger size, but blogger does not allow that. The low light was chosen so I could see whether the feet end up on the correct spots of the surface: their shadows just touch them, so that works! But when the innermost segment moves beyond the vertical, that segment flips around, so my rotation subroutine isn't quite right yet. I'll solve it. Meanwhile, it's starting to look real, isn't it? Now just imagine a body in between, texture on the ground, plants and shrubs with leaves swaying in the breeze, the sound of spidrid legs on the floor, and the occasional 'chikking' of the spidrid itself. I can see it already; perhaps imagination is better than animation...

Click to enlarge; copyright Gert van Dijk

Rusps! After my last encounter with them I thought some more about a possible painting. I decided it would look good as a double page spread, occupying the top of both pages. That results in a very wide format, just the thing for an animal that is itself long and horizontal. I decided to 'stagger' successive legs: segment x has the legs placed a bit to the inside, and segment x+1 has the placed to the outside, x+2 to the inside again, etc. In that way the stride might be long without the animal knocking its legs together. As there are so many legs, each one can be skinny. So I took the 3D model of a segment I did earlier, strung them together and starting playing in Vue with positions and curves. But I also needed a head, so I sculpted one roughly in Sculptris. I do not need a detailed sculpt as the sculpt is only a simple aid to produce the painting, not an end in itself. (Then again, if I did that, I could perhaps sell you models of spidrids and rusps). That is what you see above.

Click to enlarge; copyright Gert van Dijk

Here is another view of the rusp head. You cannot see the inner design of the snout, but the story is as follows.This particular rusp species, Megacrambis brucus, is very large and has an accordingly large head. It always pays to conserve energy, so moving that massive head or even the entire body to eat one bite is wasteful. It is better to stick a small head on a long neck (sauropods) or extend the reach in another way (arms, trunks, hooks). Inside the rusps' snout, technically a  'rostrum', there are rings connected to one anther at right angles to allow pointing the rostrum in all directions. Then there is one of those intriguing linkage systems that fish in our world excel at. Putting that in action extends the reach of the rostrum two- to threefold. Finally, at the end there are some grasping mouthparts. I put some more conventional mouth parts underneath; they are probably part of the overall rusp design.

Click to enlarge; copyright Gert van Dijk

Anyway, I put all he 3D parts together in Vue and played some more, seen at the top. Below you see  a quick over painting of the result. I was aiming for an overall diagonal effect in the composition, of which the shadow falling over the rusps's body is a part. I am not certain whether I will keep it though. I will keep the strong light against the dark clouds, as it helps to highlight the front whip. Megacrambis' English name will be 'Mammoth rusp', but I am not certain yet. Furaha was first discovered by Swahili speakers, so some of their names survived. I am also considering 'Mdudu Mzee' , roughly translated as 'respected elderly bug'. Any preferences?

Predatory penguin's evolution in Brussels' future evolution back on course.

Regular readers may have noted a predilection for incomprehensible titles, or let's say titles that need a lot of knowledge to be comprehensible. This one fits that bill, I think. The previous post dealt with models of future animals in the Brussels museum of natural history. One thing that struck me was that the model of a Neopygoscelis, a penguin descendant, differed quite a bit from the earlier published design. The feet had expanded at the cost of the flippers, an evolution that I would not have expected. The designers, Marc Boulay and Jean-Sébastien Steyer, explained that the actual models had been produced without much control by themselves, explaining the changes. Marc and Sébastien are working on a book about future evolution that will appear in 2014, as told here previously (you can read starting here or here).

My discussion of the odd 'evolution' of the Neopygoscelis model persuaded them to send me two photographs of Neopygoscelis as it will appear in the book, meaning 'Furahan Biology and Allied Matters' gets another exclusive preview of that work.

Click to enlarge

The photograph above shows clearly that the model maker had evolved the enormous hind legs of the museum model quite separately from the designers' ideas. The ratio of flipper to feet size clearly shows that the flippers are still the primary propulsion method of this animal. The feet with their long nails do look formidable though, but not as a propulsion organ. The eyes are large, so the animal does not seem that large to me; the size of 4 m as stated for tye museum model seems too large for this particular animal. Note that the nails differ in size between the two animals, so I guess that we are looking at sexual dimorphism here, with one a male and one a female. I do not know which one is which, though: Marc and Sébastien sent me the photographs, but no accompanying text. That is probably wise: always leave the reader wishing for more...

Click to enlarge

The image above shows a pair of Neopygoscelis in their habitat in photorealistic mode. A very nice addition. So there are now three versions of Neopygoscelis: the digital illustration  originally shown in the magazine, the grey model in the museum that we should probably regard as a largely 'unauthorised' version, and the one in this post, that will make it into the book. That is, unless the designers feel a last-minute need to change something before the book goes to press.

I have in the past reworked oil paintings, sometimes more than once, but doing so was a big job: it involved scraping off layers of paint before adding new ones, so the process was quite destructive. Working digitally means you can do the same thing without losing anything. Most older Furaha animals were designed for visual attraction than a coherent body plan, but I am remedying that slowly, whole keeping visual appeal intact -in fact I try to improve it-. There is always a temptation to go back and push and pull at a design some more. Obviously, the same temptation works for the designers of 'Demain: les animaux du futur', but there is one big difference: there is a publisher, so there is a deadline, and so at some point the image is finished and you cannot go back any more; what a luxury.

I can't wait for the book. When it appears I will write about it here, and perhaps earlier than that as well...