Pteranastera
- This article is about the specific clade of spardis that are capable of flight. You may be looking for Pteranasteramorpha, the clade that contains all spardis.
Pteranastera (meaning "winged frog-stars") is a clade which contains all flying spardis. They are a subgroup of the broader "spardi" clade, Pteranasteramorpha. Though not all spardis are technically members of Pteranastera, it is very common for people to say "spardis" when they only mean to refer to pteranasteran spardis.
Anatomy
Pteranasterans, as stinzers, typically have four limbs in a diamond arrangement, but the front limb--the "raptorial arm"--is placed very far back on the body and is often reduced. As in most other tripods, all limbs are attached to a single solid girdle, the pelvic ring; in pteranasterans, the pelvic ring serves as a major attachment site for flight muscles, including the ventral faces being modified into a keel.
Ancestrally, the anal arm of Pteranasterans is long and skinny, reducing its weight but restricting the potential size of their offspring.
Locomotion
Pteranasterans are ancestrally capable of flight. When not in the air, they typically move in a sprawled bipedal posture.
Notably, the Long-Footed Spardi regained use of the raptorial arm and became a tripod--but with the middle leg in the back instead of the front, unlike other stinzers.