18-Scorpii-4 Fauna: Basal Octopods

The octopods of 18Scorpii form the second dominant group of the planet's macrofauna. Classified at the base of this group of four-legged animals, there is one group whose appearance is reminiscent of ancient animals from our world.
This group was nicknamed after known Earth animals that appear to have merged, resulting in the animals of this group: the Amphibian-Arachnids (code name: AAR).
Currently, three subgroups of these AARs have been identified, with a strong difference in morphology between the first and the other two groups, but sharing many common anatomical details and, above all, a fairly similar biological development, requiring high humidity (like Earth's amphibians).
The first group classified as AAR appears to be the most basal of these; it has been nicknamed "Salamandr." Recognizable by their streamlined bodies and limbs adapted for swimming or crawling in humid environments, their behavior has been poorly documented because these animals appear to be rare or elusive.
The second group was initially named "tarantula frogs" but was later simplified to "Kaeru" (the Japanese word for frog). This group is distinguished by its stockier build, large rounded jaws resembling two large pincers, and eight short legs with disc-shaped pads. Most are ambush predators or opportunists.
The third group was classified in the same group as the "tarantula frogs" before being placed in their own group. The reason is that although their bodies are quite similar to the "Kaeru" in their stocky build and eight-legged gait… but their mouthparts are quite different, featuring a larger labrum, the absence of disc pads, and, most notably, an abdomen with long, feathery structures. This characteristic, along with their ability to produce a very unpleasant-smelling ammonia-like fluid, has earned these animals the nickname "MuffetBugs."