Iarans

Overview

Iarans are found all across the oceans and rivers of the world, but are concentrated mostly in colder waters in the north, especially in the aptly named Iaran Gulf. They are a more basal form of merfolk than Nix, who have since evolved in a more traditionally fish-like direction. Iarans have smooth skin like that of a ray, cartilagenous skeletons, simple, lobular fins¹, and countershaded, cryptic coloration. They are known by tellurans for their song and have been the subject of superstition, especially by sailors, as result, but are more often held in kind regard for their medicinal and scientific achievements and their closeness to telluran societies.

Physiology

All merfolk are predators, but iarans are strictly carnivores, while nix are omnivores. Iarans also historically lived farther out in the oceans, in the abyssal plains, than nix, but they are now found almost anywhere the water is deep enough to support them. As such, iarans have retained a camouflage in their coloration that nix now lack. Skin colors range from off-white, silver, grey and tan to black, deep brown, and blue-grey. Some exclusively river-dwelling iarans, over generations, have adopted greener hues, but these are rarely seen in marine environments. Almost all iarans sport countershading- lighter undersides and darker backs- to better blend into their oceanic environment.

Iarans possess a pair of lung-like air sacs that allow them to sing. They cannot breathe with these- no gas exchange takes place- but they inhale and exhale to move air across structures almost identical to mammalian vocal chords, making sound. In deep evolutionary history, this ability was used to lure tellurans for predation, but extant merfolk, no longer humanoid predators, have honed it to speech as well as song.

Since they don't use them to actually breathe, iarans exhale all of the air from these air sacs when diving so it does not impede the function of their swim bladder. The passageway closes (they do not need to conciously do this) to prevent it from filling with water until they surface once more. Upon surfacing, they need to again fill the air sacs before they can speak or sing. In the case water does enter, it must simply be expelled before they can speak once more- an uncomfortable, but ultimately harmless, process.

Iarans have a nose structure, but it almost purely aesthetic for mimicry purposes- it is not connected to the mouth or the air system. The nostrils, actually, are only small divets, not connected to any cavity at all. They do house chemoreceptors, giving iarans (and all merfolk) a sense of smell underwater, but it's not a terribly acute sense. Because they lack nasal sinuses, iarans lack the 'head voice' of most humanoids. Iaran's song, then, is more consistently full and resonant, though, essentially, still very often in higher pitches, as their vocal chords themselves are slightly shorter to give them a 'feminine'-sounding voice. All iarans speak and sing in the register typical of a human woman, regardless of gender.

Iarans are perfect euryhalines, meaning they can live in either salt or fresh water. This allows them to populate inland waters as well as marine ones, leading to river and lake populations of merfolk as far inland as they can physically find their way to.

Language

Iarans, like nix, converse primarily in Optimana, a sign language developed by nix for use underwater. Most also know Sign: a similar language shaped by telluran use above water. Because they are capable of speech, however, most iarans are also fluent in Solan, used to speak with tellurans and ocassionally with other iarans above water. Their vocal ability makes many iarans function as translators between nix and tellurans when necessary, though if a telluran lives in an area populated densely by nix, it is considered polite to learn Sign to dissolve this language barrier.

Culture