Sheet Spardi
The Sheet Spardi, named for its broad flat shape, is a Spardi which has abandoned parachuting in favor of only gliding, increasing the extent of its patagia to include its entire anal arm. It has greatly enlarged its anal hand, creating more surface area than it would have otherwise. Its climbing ability has also improved as a result, its left and right anal fingers being very useful for holding onto branches. Like its cousin, the Monket, it relies on arboreal flora and other spardis as a source of food, but it is far less predatory, allowing for niche partitioning—Monkets eat more meat than flora, while Sheet Spardis eat more flora than meat. It catches prey with its lateral mandibles, and it breaks into flora with its “normal” jaws.
Notably, the Sheet Spardi has finally resolved the issue of bite strength and ocular injury. Compared to distant ancestors, the quadrate vertebra is almost completely inside-out, placing the attachments for the jaws on the outside of the skull instead of the inside. A pair of zygomatic arch-like ribs jutting from the frontal vertebrae—two in number, due to a duplicated gene in the Sheet Spardi’s ancestry—curve around and join to form a Y-shape, adding more space for muscle attachment for both the lower jaw and the lateral mandibles and supporting the eye to some extent. The eyes are also placed further forward on the skull. These changes allow the jaws to be much stronger, as the muscles involved no longer have a size limit and they have no impact on the eyes. They are still limited to a simple hinge joint, however; as mastication with the tongue is efficient enough, there is little need to go much further. Regardless, this gave the Sheet Spardi access to the jaw strength needed to break into the comparatively large petrolignopsid crystals.
As the Sheet Spardi’s climbing method made having a large raptorial arm disadvantageous, its raptorial arm is smaller. However, it is not vestigial. Patagia stretching between its fingers and the underside of its body arm have made this limb effective for a new purpose: holding its babies. Like the roamers of another time and place, the Sheet Spardi carries larval babies under it with this hand, now known as an arm-pouch. This allows it to quickly transport its babies as the need arises. Indeed, it will even give birth directly into this hand by curling its anal arm so that its cloaca is positioned over its raptorial palm. Males also have this feature, so if his mate is injured or the babies need to be transported quickly after already growing significantly he can provide assistance. When not being transported, babies will still reside in trees clinging to branches with their rope-like limbs. Like its ancestor, the Sheet Spardi gives live birth to pseudo-radial larval young and it hibernates under leaf litter in the winter.
Mating
With its ludicrously massive anal hand, one would expect Sheet Spardi mating to involve equally massive hand-holding. Indeed, the default instinctive method is to face away from one another and clasp their anal hands together. However, as mating is usually done in trees and the Sheet Spardi’s center of gravity is far behind the limbs it will be using to hold onto the branch, this can sometimes be difficult to accomplish without one of them losing its balance and falling—and pulling its mate down with it. Pairs which have had this happen to them once may attempt to approach the act differently in the future, resulting in the emergence of several new positions.
A common method is for the pair to lay on top of a branch, either facing one another or laying side by side in opposite directions, with their anal arms hanging down and clasping beneath them. This method has its own challenges, however: they cannot do this successfully on a branch that’s too thick, and if it’s too thin it might snap under their combined weight. The risk of losing balance and both spardis falling out of the tree is also still present. Another method is to find a stable location, such as a tree hollow, and mate belly to belly either laying on their sides or with one on top of the other, still holding hands. This method is the safest in terms of not falling out of the tree, but suitable locations cannot always be found.
There is one method which balances safety and availability: mounting. This is accomplished by one standing on a branch, using the left and right anal fingers like a pair of legs, and moving its middle anal finger out of the way so that the other can climb on top and curl its anal hand underneath. Whether the male or the female is on top doesn’t matter, as they are still merely performing a cloacal kiss. This method can be done anywhere and has very little risk of the pair falling from the tree, and even if they do it will usually only be the one on top and not both of them. However, this method also comes with the downside of putting pressure on the back of the one on bottom, which would remind it instinctively of a predator attacking from above. While the Sheet Spardi is intelligent enough to recognize that this is not the case, this can still make the entire act incredibly uncomfortable, so very few pairs have this as their preferred mating position.
Ordinarily, in any given species which must change its mating method, eventually one will win out and become the new instinctive method. But with no single good option and the objectively “best” one potentially requiring a necessary survival instinct to be dulled, a given mated pair of Sheet Spardis must decide for themselves which mating position works best for them. This has resulted in them potentially being the least intelligent species in all the cosmos where individual-specific mating position preferences are common across their entire population.