Tuesday, 24 December 2013

Influence of the rostrum linkage system on forage volume in Brontorusps (Brontocrambis brucus)

A Christmas Special!
Ahead of the normal schedule, and with dinosaurs, rusps and biomechanics!

Click to enlarge; copyright Gert van Dijk
The title of this post sounds like that of a proper scientific paper, doesn't it? Something out of the 'Journal of Astrobiological Biomechanics', I guess. It's time to look at rusps again. My big rusp painting is finished, and as it is meant as a double-page spread, it is large: 7200 by 2700 pixels. A spoiler is shown above showing a fragment of a rusp in the background of the painting. The fragment has been halved in size and its area represents just 2% of that of the entire painting. The painting is based on earlier sketches. For more on rusps, either visit the main Furaha site or look at these posts: sketches, anatomy, predation, concept paintings, etc.  

The evolution of new Furahan animals gets more complicated with time. In the beginning I just sketched a pleasing shape and started painting right away. Now, I worry more whether the animal makes evolutionary, mechanical and ecological sense. Well, up to a point; this is science fiction and supposed to be fun, after all. 

Here are some of the steps in rusp 'ontology': they started with some quick sketches, and then the slow evolution began: successive legs were offset medially and laterally to avoid legs bumping into one another, followed by an arrangement for their skeleton. Their fore and aft whips are long and held horizontally rather like the tails and necks of sauropods, and hence have a similar system of internal trusses as compressive elements at the bottom and ligaments at the top to withstand tensile stress. The whip is held up passively by these forces, so avoiding the high cost of doing that with muscle force only. The last stage involved refining the head of the rusp, and in particular its snout, or 'rostrum'. In an earlier post this rusp species was called Mammoth Rusp / Megacrambis, but now it is the Brontorusp / Brontocrambis; yes, that means 'Thunder Caterpillar'!  The Mammoth Rusp still had some intricate limbs functioning as additional feeding aids under its snout. I was not too certain of that arrangement, and my doubts were confirmed by comments on that post. So the Brontorusp no longer has these additional mouth parts. The thing is, now we have a massive animal with a large head. How does it feed itself?

The mouth of the rusp is in its head, which seems obvious but in speculative biology not many things are obvious. Also note that rusps are large herbivores: they need a lot of food and spend much of their time eating. Moving about is costly, so it would be best if they moved the least possible amount to get their food, which does not sound as if there is much room to save energy. Let's tackle that by considering the problem of getting an animal's mouth on vegetation; there appear to be four solutions to do so; rusps use the fourth, but we'll come to that. The first solution, always necessary as vegetation will not come to you, involves walking to the food source.

Click to enlarge; copyright Klein et al; Biology of the sauropod dinosaurs. Indiana University Press 2011
But once an animal arrives at its 'foraging station' a nice way to save energy is to keep most of the body motionless and to have a long neck allowing the head and mouth to move about independently of the gut. For very large animals, needing to feed all day, it pays to divide their anatomy in mouth and guts; the rest is just 'other bits'. Sauropod dinosaurs used that method, and the image above is from a study on how far sauropod mouths could reach, depending on neck length and leg length. The idea is that the neck can move in a horizontal plane 90 degrees to the right and the left, and in a vertical plane straight up and down. If the animal is lying on the ground the volume of space that it can reach is one quarter of a sphere. If the base of the neck is higher up, when the animal is standing, the volume increases. The authors assume that the bottom part of the volume then is cylindrical whereas I would assume that to be spherical as well, but never mind.

Click to enlarge; copyright Gert van Dijk
Swans and geese have very flexible necks and can probably reach every point within that envelope, but if an animal has a neck less flexible than a swan's, only part of the volume is accessible to the mouth. If this is the first time you realised that geese and sauropods might have long necks for a similar reason, good!

The image above shows an adapted 'forage volume' for a sauropod: the outer red sphere is the outer limit of where it can reach, and the inner blue sphere represents the inner limit, assuming that the neck is too stiff for the animal to reach a point closer to its body. The human ('Marlene') is just there to keep the sauropod in its proper place. 

The third solution to get the mouth near food is to use an appendage to shovel food towards the mouth. The best example I can think of is the elephant's trunk, which greatly increases the elephant's reach. The erstwhile rusp mouth limbs were short and not at all good as harvester limbs, and I did not wish to elongate them tenfold; they are gone. I also did not wish to turn the whip into a grasping organ. Rusp whips are not built for that, although in a pickle they can probably be used to knock a branch off a tree. Instead, rusps use a fourth system which is really just a combination of the last two: they carry their mouths towards the food without moving the rest of the head. The 'mouth extender' is extensible and based on a mechanical linkage system. In itself this is certainly not a new idea: Earth fish have such systems in abundance.

Click to enlarge; copyright Gert van Dijk
This image shows a schematic view of the rusp rostrum. Start with the red shape in the foreground: it consists of two V-shapes starting from a vertical axis. All places where elements meet are in fact joints. The pink axis shows that the whole ensemble can rotate, but it can do other things as well: if the two Vs rotate towards one another, the whole shape will become longer and narrower. At its right end, the shape ends in two points on a horizontal line. Now copy the shape, rotate it by 90 degrees, and you get the blue shape in the foreground. The two points where the red shape ends act as connection points for the blue shape. Once connected, some movements from the red shape are connected to the blue one, but not all, and that makes the rusp rostrum quite versatile. In the back you see how the rostrum is formed by stringing red and blue shapes together. In reality the trusses are not formed by straight bones, but by curved ones, so the section of the rostrum is circular rather than rhombic. The cylinder on the right attempts to show the outlines of the bones on a cylinder.

Click to enlarge; copyright Gert van Dijk
And this image shows an as yet unmentioned aspect of movement: if the two starting points are brought closer together, this changes the section of the rostrum as well as its length. The right one is extended, the middle one shortened, and the right one is in neutral position. I expect rusp rostra (yes, that's the plural) to be able to double in length.

Click to enlarge; copyright Gert van Dijk
But we need more flexibility, and that is achieved by rotating the shapes and using the angle between the Vs for additional control. The stylised skeleton in the back shows what can be achieved. So there we are: an extensible and steerable system to get rusp mouths where they would otherwise not reach.

Click to enlarge; copyright Gert van Dijk
Here are two views of an adapted Sculptris model of a rusp head. I take it you will recognise the system of trusses under its hide.

Click to enlarge; copyright Gert van Dijk
And finally, a schematic rusp foraging volume, rather like that of the sauropod (the whip of this model is truncated). Note that the rusp can access a larger portion of the outer foraging volume than the sauropod. The volume itself is smaller though, as rusps are smaller than sauropods, and their rostra extend their reach, bot nearly as much as the sauropod's neck does. Marlene is standing in the forage volume, something I would definitely NOT recommend! In practice, rusps are ground feeders, not bothering about high branches. Have I told you about the ecology of the spotted plains where they live, where post of forests alternate with plains and how rusp feeding habits are to blame for that? No? Oh well, that is another story.  

Saturday, 14 December 2013

More future evolution in Japan

Sometimes I like to revisit sites to see whether there is anything new. In this post I will show a few interesting species that came up in this way. The site in question was visited in 2010, and shows the work of the Japanese author and illustrator Satoshi Kawasaki. He specialises in palaeontological illustrations but does not shy away from extending the time line of his work well into the future, up to 200 million years from now, in fact. In palaeontological papers and books you sometimes read 'mya' as an abbreviation for 'million years ago'. As the world of speculative biology is less hampered by ugly facts, perhaps it could profit from having a similar term for 'million years from now': myfn, or perhaps 'million years on': myo.

Click to enlarge; Copyright Satoshi Kawasaki

As I wrote before, Mr. Kawasaki has the sense of humour that allows him not to take his creatures equally seriously, something I like very much (I find mere monsters boring). Some of the animals on the pages showing life 100 and 200 myo are apparently drawn by other artists than himself, so het lets others play along, another nice trait. I would have like to exchange emails, but previous attempts to contact him failed. Let's have a look at some of the creatures.

Click to enlarge; Copyright Satoshi Kawasaki
In Google's translation this one is called 'Nereusu'. By omitting some of the Japanese characters I found out that Nereusu is simply a transliteration of the Japanese characters, so I could not translate it.  I therefore suppose the name refers to Nereus, the mythical being from classical Greece Nereus, who was after all as sort of sea god. Somewhat ironically, there is of course another Nereus in speculative biology...

Anyway, the animal is obviously a large marine predatory bird descendant (probably descended from penguin stock). Students of speculative biology will note that such creatures are very abundant in fictional future seas, as they apparently tend to evolve in the minds of many creators. I do not really mind if such a concept is not completely original; after all, all of science fiction is full of common ideas. While I applaud originality, there is also pleasure in seeing a job well done. Mr. Kawasaki is a very adroit illustrator, and this is an excellent 'future orca-like penguin-descendant marine predatory beast'.

Click to enlarge; Copyright Satoshi Kawasaki
Have a look at this drawing, and you will probably guess what it is about without having to read the text. It can only be a social crab modelled on the pattern of ants, bees and similar colony dwellers. There is one giant 'mother' laying lots of eggs, here very neatly held in a redeveloped abdomen. The ones in the front must be soldiers, and the little ones in the middle must be workers. I cannot see whether or not they have pincers, but assume they do; otherwise, what will workers work with?

Click to enlarge; Copyright Satoshi Kawasaki
Sometimes Mr Kawasaki works on a theme; in my previous post I showed terrestrial cephalopods (I know, I know...), and this time I will focus on a group of his animals that do not seem to enjoy the common attention of future evolutionists: starfish! There is only one on the 100 myo page, shown above. It is not drawn by Kawasaki but by someone else. It may also be the most original of all the future Asteroidea ('starfish'). You cannot beat Google Translate for creating a sense of wonder, particularly where one was not intended: "One of the arm portion becomes large, the remaining portion forms a head lump pseudo part." I guess we would have guessed that anyway: four of the five original arms have shrunken and are now appendages around what is now a proper head. As a result, the animal is now bilaterally symmetrical. I do not quite see how evolution would set off in this particular direction, but like the result. I do not think I have seen anyone else designing this before, either.

Click to enlarge; Copyright Satoshi Kawasaki
The world of 200 myo has more future Asteroidea.The one above is a pseudoplant, a Parasasuteru. It lives in Australian swamps and -I think!- envelops animals moving in its shade, only to digest them at leisure.

Click to enlarge; Copyright Satoshi Kawasaki
And finally, one I rather like: the 'Di pedal stell' ; could that be a 'bipedal star', I wonder? If you count the number of limbs, you will find six rather then five, but the texts suggests that one of the original arms has split to form two legs: "Part of the two-that looks like a foot is what arm once was transformed." Probably. Have a look at Mr Kawaski's site for other interesting creatures, or, if you like palaeontological illustrations -who doesn't?- visit his pages of the past world.

And now something somewhat different
I have been looking for other projects of speculative biology, but have not found any new ones. I searched in various languages, albeit my skills are limited to Germanic and Romance ones. If readers know of projects that deserve attention, let me know, particularly ones I am likely to miss, such as ones in Slavic or non-European languages.

Finally, I have begun considering ending this blog. It is in its sixth year and I feel that some of the freshness has gone. The number of readers has not diminished, by the way: it is stable and in fact grows slowly. I find it a bit more difficult to come up with new subjects, and after more than five years the blog has perhaps become a fixture in the little world of speculative biology, not something that attracts much attention. Perhaps blogs are a bit like television series; at some point you stop caring about the characters, and that may be the time to consider a final episode. 

Sunday, 1 December 2013

Red leaves, swaying in an alien breeze...

Readers who have followed my series of posts on alien plants and photosynthesis (here, here and here) will know that I have no objection against plants on other world not being green, so that is why there is  'red' in the title of this post. But this post will not be about photosynthesis, as I think that theme has been dealt with sufficiently. The next theme on plants will probably be about biomechanics, but I have not started that one yet.

This post is about portraying alien plants. Obviously it is possible to do a painting, and that is fine, but it is also a lot of work. Can't computers do part of the work? There are not that many software choices available to populate a landscape with alien plants. The one I have been using over the years is Vue by E-on software. Vue is difficult to handle, in part because there are many options that are not all well-explained in the manual, but also because the software can be very unforgiving depending the hardware you are using. In other words, it may crash. It is the kind of programme that you can easily develop a love/hate relationship with.

It has an ecosystem feature, in which you choose plants or objects, adjust their rations and relative sizes, and when you then press 'populate' the programme does just that. It can even take matters such as height or slope of a landscape into account, placing some species there and others not. The problem in designing alien forests was that Vue's innate plant designer was inadequate: it let you design variations of Earth plants, but made it impossible to design something more interesting from scratch. For that I used XFrog 3.5, a programme that allows the user to come up with intricate new shapes. The XFrog plants could be imported into Vue, and did allow worlds to be populated with alien plants. Some examples of my earlier efforts are here for Epona and here and here for Furahan swamps.

However, there was one disadvantage: Vue's own plants could sway in an imaginary wind, but the imported XFrog plants were static objects. For static images that is obviously not a problem, but for animations a forest in which no leaf moves is just odd. I have stopped doing Vue animations for that reason.

Recently, E-on introduced a new programme: The Plant Factory (TPF), which does let the user design plants from scratch, with the promise of having the result sway the wind. That was attractive, so I decided to try it, even though the user forum made it clear that this is a typical E-on product: it can do amazing things but often in a roundabout or unexpected manner, and sometimes it simply does not deliver. TPF has no manual whatsoever, so anyone wishing to use it should treat it as a voyage of exploration rather than as a productivity tool. There is a 'personal learning' version, so everyone can test it without spending (rather a lot of) money on it.

Click to enlarge; copyright Gert van Dijk
 I first tried whether I could make it design oddly shaped plants, and here is one of first attempts. I tried to obtain a results resembling an earlier XFrog design, and that went reasonably well, as you can see above. As you can see, this tree has its major branches growing from a central trunk as do Earth trees. Its branches curve through the air to reach the ground, where they may take root, providing water and nourishment or simply offer structural support. The proportions are not right yet, it is a start.

Click to enlarge; copyright Gert van Dijk
The image above shows a hillside populated with two species of simple plants, home made in TPF. The scene was intended to experiment with wind animation. The first result was disappointing in that there was hardly any movement. There are lots of sliders controlling wind, which I had left at their original settings. Apparently those are meant for an unnaturally calm day. Very well, let's turn the wind setting up to 100%. That did not do too much either. I remembered an earlier surprise in Vue, dealing with lens blurring; there too a setting of 100% was almost negligible; someone at a forum told me to not to treat 100% as a limit, and so here too I set wind animation to 500%, and now at least the leaves move. Apparently this is more or less a dimensionless unit; just one of those odd Vue quirks.

And here is the result; better, I think! It's not a storm yet, but at least there is movement! The quality of videos on blogger is not very good, so it can look a lot better. Meanwhile, there is still a very large number of options to discover or, given the lack of a manual, to blunder into, so do not expect a to see a marblebill brachiating through a Furahan forest. Not quite yet, anyway.