A marblebill in progress (also known as the becdacier)

No time this fortnight to write anything elaborate, unfortunately. Some posts take much more time than others. The ones that take most time are those that require checking the physical aspect of some matters, not just because finding sources and digesting the content takes time, but usually also because I then need to do some programming of my own or I have to make some specific illustrations. In short, the heavy science bits take a lot of time. Over the years I have written quite a few words on such subjects, and I started wondering whether I should perhaps bundle them, work them over, write some new chapters, and produce a book on the biomechanics of alien life. Something like 'Darwinian creativity in a Newtonian Universe'. The title is probably much too enigmatic for the book to sell, but perhaps it could be a subtitle. Mind you, it would be completely separate from the Furaha book. But would anyone buy it? Let me hear what you think.

Anyone, I have been working on an update of the marblebill. I showed you another such update once before, and the marblebill is on the Furaha website but featured previously on this blog as well. You may recognise some general update principles. The eyes on stalks are now less prominent, but certainly still occur in various species. There is also eye specialisation. The images below are taken from the sculpting program Sculptris, a free programme I recommend unreservedly.

Click to enlarge; copyright Gert van Dijk

The marblebill is an arboreal brachiating predator, and has two forward facing eyes to help it judge distances and fixate its prey. As is the case for dragonflies, the size of the ommatidia (the individual eyelets in a compound eye) depends on where you are in the eye: they are smaller in the part of the eye facing directly forward. This increases visual resolution at the price of sensitivity to light. The marblebill is a diurnal creature, which makes sense I think: you would need impossibly good vision to allow an animal to hurl itself from branch to branch at high speed at night.

Click to enlarge; copyright Gert van Dijk

There is another pair of eyes, the 'oculi posteriores'. Note that these were not posteriorly placed in ancestral hexapods, whose four eyes were placed around the head. What became the anterior eyes were once the bottom ones, and the posterior ones are the former upper ones. Anyway, in the marblebill lineage the upper ones, alresdy in the posterior position, over time migrated outwards, providing an all around vision, not just in the horizontal but in the vertical plane as well. For an animal living in three dimensions this is more important than for a grazing animal. One result is that it would not be easy to sneak up on a marblebill. Not that there is any other predator up there in the trees that would perform such sneakish acts anyway: it would be too dangerous. The marblebill also does not need much vertical vision for its territorial disputes, as these involve no sneaking whatsoever, but are announced frighteningly loudly. But detecting prey is another matter, and for that these eyes are superb.

Click to enlarge; copyright Gert van Dijk

Here is the painting in progress. I used to work out perspective and draw everything completely without any aid except for the occasional ruler, but I now make use of what the digital age has to offer. So I exported the sculpted head into Vue infinite, made certain the lighting came from the correct direction, adjusted the perspective angle and produced two renders. Cut out the head, place them on a separate layer in Painter 12 (to be deleted later), and everything is in place to start painting. Now all I need is the time to do so...