Originally from the Navareo System, Navareans are a humanoid species that was brought into the system by one of the precursor comets. They evolved into more or less the same species on all five planets and maintained cross-breeding capabilities.
They are a sexually dimorphic humanoid species with a two-stage cardiovascular system that pumps purple blood through their system, with their two hearts being responsible for oxygen rich and oxygen deprived blood respectively. Its purple colour comes from the oxygen binding protein Hemerythrin that binds oxygen and transfers it through the system to the other organs.
Genetically, they are unique in the galaxy in that they have a triple-helix DNA that is highly resistant to ambient modification and mutation. This caused them to evolve very slowly - in fact, it is believed that proto-Navareans looked more or less identical to their modern versions, albeit with less evolved brains.
Another quirk is their ability to produce a wide range of dye proteins that leave a colourful residue in body and head hair. However, they can only produce one of the about 30 different colours - making their hair colour genetically coded. Colours range from the entire spectrum from red to blue, with colder colours like violet and blue being more common due to being dominant traits.
Not much is known of this gelatinous silica-based species. The Varyn are amorphous, presumably single-celled organisms that are made of silica-based gel that conducts neural activity. Essentially, Varyn are all brain - and neural activity is carried through their entire bodies. By shifting biomass to different parts of their body and changing local density, they can simulate facial expressions, appendages and even vocal cords.
Varyn are sexless and genderfluid, meaning that while they do not have physical identifiers of their sex, they have since the contact with humanoid di- and trimorphic species started to identify on a spectrum of gender - usually the dimorphic model most of the galaxy is familiar with. Their gender identity changes with their mood and the situation, and most Varyn choose to represent this with their bodies.
With the exception of indigenous Varyn that reside on the surface of Planet Varyn (which is comprised of the same biomass as the Varyn themselves), Varyn usually choose to take an approximate humanoid form with a head, a torso, two arms and two legs, although this standard can be deviated from at any time if desired.
Varyn reproduce asexually by mitosis and acquire energy though an as of now barely understood process similar to photosynthesis. This however does not mean that they do not posess libidos - in fact, while little is known of sexual desires and pleasures in Varyn pre-contact, many humanoid-varyn sexual relationships are documented.
While visually almost indistinguishable from Navareans, Talosians have a vastly different biology. Research and restoration of the Opportunity Archives lead researchers to believe that Talosians and Humans share a common ancestor - the most probable theory is that a precursor comet brought their common blueprint to both the Sol and the Eris system. However, this is statistically impossible.
Like humans, they are a dimorphic race that reproduces sexually. A quirk of their anatomy however is that they, if they are born on Talos and exposed to the sunlight of the Eris for their childhood years, never develop Melanin. This is because the star of Eris does not give off UV light, so Melanin production will not be triggered. However, simulated sunlight and onboard spaceship lighting give off trace amounts of UV, so while Talosian grounders will always be as white as possible, satellitists and stationeers usually have a darker skin tone.
A bipedal amphibian species that is known for being brilliant scientists and engineers. Their brains are impressive biological computers that work on a very different principle than mammalian brains - instead of having motor and sensor corteces, the respective muscle regions have autonomous control that is only influenced by their cognitive cortex.
This causes their actual brain to be able to work much more efficiently - evo-devo-biologists believe this incredible capability to multi task is a remainder from the era when Delta were primarily ocean-bound. Quick movements and avoidance of predators was important, so movement was relegated to the periphery instead of being an active decision process.
Ever since the planet of Delton fell to a massive ecological collapse, all remaining Delta holed up in one of three cities that form an atmospheric triangle around the only source of water on the planet. The Delta had to learn to adapt, and billions of their kind perished.