Thalassan

Biology

Anatomy & Morphology

Thalassans are somewhat cephalopod-like shelled dodecapods, possessing a segmented shell-like exoskeleton that can either curl into a spiral shape or unfurl to a straight, almost blade-like flattened cone. The open end of the shell has a wide, crescent-shaped plate to protect the soft body of the creature, whose beaked mouth, eyestalks, and twelve tentacles emerge from the chitinous shell. Nauts are unique among known sophonts in that their vascular system relies on not one but two oxygen carriers: hemocyanin, a copper-based protein that turns bright blue when oxidized; and chlorocruorin, an iron-based protein that turns light green when oxidized.   Thalassans can walk terrestrially on their tentacles under gravity up to ~4 m/s², but since they are dependent on internal gills for breathing, their spacecraft are typically filled with water. This allows them to move about much faster: they jet-propel themselves with their spiracles in a manner similar to terragenid molluscs.

Perception & Sensory Capabilities

Visual

Thalassans are highly visual sophonts, having unique triocular vision facilitated by three compound eyes with millions of tiny crystalline lenses. These eyes are sensitive to a broad range of the electromagnetic spectrum, from near-infrared all the way to high-frequency ultraviolet. Color is a critical part of Thalassan written language, which is why other species struggle to read it.  

Auditory

Thalassans have considerably worse hearing than other known sophont species, though they are still capable of discerning auditory input. Their auditory sense is facilitated by a pair of statocysts; small, sac-like internal organs containing a mineralized mass and lined with sensitive filaments.

Ecology

Geographic Origin & Distribution

There are two major populations of Thalassans. The population which remains on their homeworld are traditionalists, having dismantled most of their more advanced technologies -especially those that emit excess electromagnetic or chemical signatures. By contrast, the exo-Thalassans are highly advanced spacefarers but also reclusive xenophobes, opting to only inhabit a scattering of solitary substar systems. How they travel between these systems is uncertain, though some scholars theorize that the nauts have mastered traversable wormhole technology. In any case, the exo-Thalassans almost never leave their refuges, barring a major catastrophe.  

Habitat & Survival Factors

Though they can operate out of water for extended periods of time thanks to internal water storage chambers, the nauts are highly dependent on water for their survival as it is their primary medium of respiration. Thalassans are quite technologically adaptable, and thus they will manage to survive if given an environment with liquid water of appropriate dissolved oxygen content.