So, this may not be entirely the best way to start things off, but I'll stream-of-consciousness this and we'll try to re-organize my thoughts later, so please forgive me if some snippets appear unlinked to a greater narrative (bit tired, running low on caffeine, simulations had to be restarted, batch queuing system had to be circumvented, all sorts of assorted "fun")
Firstly, please don't take anything said in the following as anything other than a detailing of my reactions and thoughts concerning to the differences between my ideas for the Aera and what has been drawn. I'm very pleased that this is being worked on, and I appreciate the difficulty that comes from working from the limited visually-oriented information existing. Generating the aforementioned has proven far more difficult than I ever initially imagined it would be.
The first thing I think about is how this corresponds to the distant ancestors of the modern Aera, with forelimbs less specialized, and a hexapod gait. I am constantly regretting the use of the term "centauroid" in their initial description, as all I really meant at the time was "has two limbs that are used primarily as 'arms' and four 'legs' in the human sense of the manipulator/locomotor split between 'arms' and 'legs'. When I envision the Aera, I always start by thinking about them, not in their alert, active, somewhat upright posture for local manipulation, but in their nearly-parallel to the ground moving posture.
The legs on your drawing seem to me too short - as mentioned in the wiki, if a large Aera measures the better part of 3 meters from tooth to tailtip, then that Aera will be around 120cm or so high at the shoulder (we could call it a hip, if that makes what is being measured any more clear). The four legs are all noticeably stocky in comparison to the arms, easily differentiating the forelimbs as manipulators and the legs as primarily locomotors, but they aren't stodgy -- the Aera is not without agility. The midlimbs are the most stout, being capable of supporting an Aeran's body weight -- in a sense analogous to how a human can stand and, to limited degree, maneuver on one leg, an Aera may balance and shift on it's midlimbs. The toes on the midlimbs are the strongest, and least dexterous, but can provide a vise-like grip. Aeran hips are extend somewhat up and to the sides, interrupting their streamlined form. The hips for the midlimbs orient the midlimbs at minimal side-splay, allowing a primarily fore-to-back progression when running. The longer rear limbs are offset just enough to the side and splay that they may swing outside the midlimbs when running. The rear limbs are just long enough they must remain slightly bent when the midlimbs are erect, and the body parallel to the ground. The rearlimb toes have a coarse dexterity, but also the most prominent remnants of what were once impressive multi-tasked claws, still dangerous in anger and of utility in tree-purchase, if no longer vicious. The Aera are still prone to make use of their arms when running, not for propulsion, but as a maneuvering and braking aid (remembering that the Aera evolved amid the cluttered underlayers of vast, sprawling, mult-canopied forests, and even and flat terrain was extremely rare while undergrowth and above-ground roots and vines and whatnot were extremely common)
The somewhat upright stance of the Aera is more of a sitting affair than a standing one, with the tail and rearmost body touching the ground, and the midlimbs locked into a slightly foreward position, propping up the fore-torso as it angles up.
The bulk of the fore-torso is taken up by lungs that extend most of the fore-torso's length, although the two (primary) hearts (of the four total Aeran hearts) are also sizable and located in the fore-torso. The esophageal pipe passes through to the rear body segment. Aside from assorted glands, the hearts and lungs are the only notable organs in the fore-torso, the vitals being relegated to the rear-body. There are two lungs, but each is asymmetrically bifurcated.
The shoulders on your Aeran sketch, one might even say, the fore-torso taken as a whole, is somewhat anthropic, and this is not as I envisioned. The Aeran fore-torso, like it's entire main body, though not cylindrical, is not as broad and flat as a human's, and the arms do not sprout from the vertical terminus of the torso, free to twist up and in to frame a neck, but have a somewhat more lateral origin. This difference is heavily linked to the Aeran neck having to be much more significant in girth in order to support the Aeran head in a non-vertical position. The Aeran neck is nearly as wide as the torso, and the skeletal attachments for some neck muscles interplay a bit in places with the positioning of the arm attachment points.
As for the head (ever a mess of details)---
Jaw: Only runs ~2/3 - 3/4 the length of the head
Eyes: Further out from the rest of the head, orbital socket > 180 degrees & independent eye tracking => can both focus both eyes on forward target and glance backward with either eye with limited body movement (i.e. not breaking stride)
Tympanum-analogs: hard to see presence in current sketch
Vocal-rumblers: should be visible on the underside of the head-neck joint region.
I think we would be well served to move a little bit further from some aspects of familiar forms. We should remind ourselves that we don't have to work from the single-spine-with-ribs-and-head-and-tail form that terran vertebrates are formed around (admittedly, form and function are not unrelated, but there are more than fish in the sea (to mangle a metaphor). ). I happen to like thinking of Aera with three, hip-interrupted vertebra-esque columns (two dorsal and one ventral, with ribs from each partially overlapped/interleaved rather than fused), but it's not key to my vision of them. What is key is that, even if, as with the Rlaan, we cannot escape some sort of semblance of familiarity, even if only in chimerical form, the Aerans are visibly clearly alien, and appropriately unsettling in their alien-ness.
For the skin, it would be nice to see some lenticel-like patterns (like those seen on a birch tree
http://upload.wikimedia.org/wikipedia/c ... h_bark.jpg )
... my apologies for not writing more at this juncture, but I'm very tired now and I'm trailing off. I'm sure we'll continue to chat about this over the next few days as we (both) try to figure out what exactly I (might have) said.