Here's a little study on a random female Armolin if you were wondering how they can vary in appearances. Basically, they always retain the heavy body armor and are always larger than the males of their species. Colors and patterns are as diverse as fingerprints and so are additional features like antennae and tailfins.

Males tend to be little bitches, to be honest. Some don't even have any body armor other than the distinctive craniums all Armolin and Pangdillo are distinguished by. Antennae and tailfins are never present in any Armolin male.

The antennae on Matile work exactly the same way as they do on any other species. They're sensory organs, sensitive to vibrations and scent. They don't actually smell with them, but rather detect chemical changes in the air around them.

Tailfins on the other hand have multiple uses for these marvelous creatures. Its where the pheromones of females are dispersed from and in larger individuals, pheromones are shed in the form of flakes. They're generally so strong, courtship can be a very fragrant occurrence. Tailfins also aid them in swimming... and on hot days, females have been observed fanning each other with them. The privilege is also shared with males and other species. Whoever's present at the time, really.