Sunday, 22 October 2017

The Trench Gobbler

For once I will show a complete painting. Well, more or less. The painting in question is part of a two page spread concerning 'Fishes VI'. The six groups of 'Fishes' are part of the hexapod family tree, with Fishes I, II, III and V as the direct ancestors of terrestrial hexapods, and Fishes IV and VI as parallel aquatic groups. Mind you, I wondered about using 'Fish' instead of 'Fishes', as 'Fish' in English can be both singular as well as plural. A singular language, English.  I found that 'Fishes' can be used to describe multiple species, so that seemed the right choice.

In Fishes VI the third, i.e. the last, pair of flippers have fused to form a horizontal fluke, very much like that of whales. The problem with making 'Fish' alien is the high probability that a torpedo-like streamlined shape is rather likely to evolve as a 'universal' feature. I chose to accept that, so 'Fishes' superficially look much like Terran animals. But they share their world with cloakfish, kwals and aquatic wadudu, so there are definitely some odd shapes to be found too. And Fishes VI are not all that 'earthy': after all, they have four jaws, four eyes, their respiratory system is completely separate from the digestive tract, etc.

The painting combines several themes. I will split it in four panels that show various species of Fishes VI in 'powers of 10', meaning each species is 10 times as large as the previous one, starting at 4.5 cm. Each panel will also show the species eating, so food webs can be illustrated as well.

Click to enlarge; copyright Gert van Dijk
This is the Trench Gobbler; I haven't thought of a binomen yet. This painting forms the second panel of the four. The Gobbler is a typical deep sea species. In this biotope, the only light is that produced by lifeforms, and these are scattered far and wide. This is in fact a very barren ecosystem, which is due to the fact that it is almost entirely based on a slow and sparse trickle of organic material from above. Before anyone asks, I do not know whether there are hydrothermal vents. Animals need to conserve energy here. The water is largely still, and there is no need to swim fast habitually. Hence, there are no fast swimmers here, so there is no overriding advantage in streamlining. If the rare opportunity to catch some fresh food presents itself, it must be jumped upon, because there may not be a second chance anytime soon. These two influences together have resulted in very odd shapes, just as on Earth. The Trench Gobbler has elongated lateral jaws to grab anything possibly edible. In this image, it is attacking a tentacled creature, probably some larval Cthulhuoid. The larva has just emitted a cloud of bioluminescent ink to try to escape, a trick that seems to be working.

Click to enlarge; copyright Gert van Dijk
And here is a detail, for once at full resolution. It is fun to paint such structures, in particular the somewhat glassy structures of the teeth and fins.      

(PS: There is something wrong with my access to the main Furaha website, so I cannot update the loading screen for a while. To check for new posts you should check here directly)

6 comments:

Keavan Ѳ said...

I wonder, do you think there's any reason why jaws/mandibles/ tend to be situated orthogonally, or come in pairs? Would diagonally oriented jaws be less biomechanically viable for the average organism?

Sigmund Nastrazzurro said...

Keavan: very good question about diagnonal jaws! Which, of course, to an extent means 'Why have I not thought of that?' I did to some extent...
Hexapod jaws started out radially: there were originally six, so only two of the six were placed either purely vertically or horizontally. I got that wrong at one point, in fact: http://planetfuraha.blogspot.nl/2013/08/hexapod-evolution-in-twist.html
Later I though more about interactions between jaws. If all that jaws have to do is drive teeth into a prey, without touching another jaw, then each jaw can be designed as a separate spear. But if the jaws have to crush a prey they probably have to work directly opposing one another's forces, and it probably does not matter much what the general direction is. With bilaterally symmetrical animals I guess that vertical or horizontal pairs are the most likely. In such cases having four jaws is probably the more difficult solution mechanically. That is just a hunch though. This assumption is probably why I often let lateral jaws evolve into something else.
Jaws can also be used as shears, and if the plane of the shears is parallel to the mouth opening, then I see no reason why adjacent plates cannot work together, and there can be many.
I need to think harder about all this; thank you for putting me on the track.

Anonymous said...

I hadn't known before that hexapods had invaded the land four times on Furaha. Intriging and fascinating.

And whether or not there are hydrothermal vents*, wouldn't really matter in the open waters of the deep sea.
* = I would assume so, but then I assume Furaha is still tectonically active.

This is a terrrific image of two remarkable criters; kudos!
-Anthony Docimo

Keavan Ѳ said...

Another question about jaws: in many vertebrates the skull is fused into the upper jaw, containing the brain and main sensory organs. Functionally, only the lower jaw moves independently of the head, and the upper and lower jaws are radically differently specialised. I've seen art of a hypothetical animal in which this specialisation was reversed, leaving the upper jaw mobile, and the lower jaw relatively stationary. It looked quite intriguing, and very alien, but I suspect it would require different feeding behaviour. To what extent is comparable specialisation and simplification present in the animals of furaha?

Petr said...

I am lost for words! Such a beautiful image!

You did not go easy on yourself here, the anatomies are alien, the lighting conditions are very out of the ordinary, and you needed to depict two different liquids interacting with one another.

The result is mind-boggling to me. I love it.

Sigmund Nastrazzurro said...

Anthony: I did not describe hexapod ancestry very clearly. I'ss try to do better: Fishes I, II and III are clades that evolved successively, with Fishes I and II dying out, mostly. Fishes III divided into three parallel groups: IV, V and VI. Of the three, only V seems to have given rise to trerrestrial descendants. this suggests that terrestrial hexpods are monophyletic, although hexpods on one isolated continent are so different that they make you wonder whether this is true.
And Furaha is indeed tectonically active, so there are probably vents somewhere.

Kevin: in hexapods all four jaws in principle articulate with the skull, so the movement of the jaws looks different from what we see in Earth's terrestrial vertebrates. but during evolution things can change, and giving up on a joint can be advantageous as it can increase stregth and is simpler. Of course, this affects the reach and direction of the jaws, so whether this happens wil depend on whether food is up, down, etc. In some groups lateral jaws disappeared together, for instance. There are highly evolved terrestrial hexapods with four fully mobile jaws.

Petr: thank you (blushing)