u/Emrozial — reddlx

Oastanian creatures do not use calcium phosphate bones, as they are incompatible with Oastanian chemistry.
Instead, they use silica-organic composite bones, which are resistant to Oastans biological chemistry.
These bones are called safís, from the greek word for clear, and the skeleton of an Oastanian creature is called the Gyasoma, from gyálino ostó, glass bone in greek.

Cartilage is also present in many creatures, used for flexibility in predators or even prey. But as cartilage also isn’t compatible with Oastanian chemistry, they use strofí, coming from the greek word for bend, strofí is a cartilage-analogue, though more rigid, it’s still a flexible structural tissue that connects stiff parts of the gyasoma to increase flexibility and support tension that’s focused in that area.

Chrysós, the red blood cell analogue on Oastan, carry fuel molecules, ( methyl hydride compounds ).
Págos carry the oxidiser molecules, ( hydrogen peroxide compounds ).
They both deliver to specialised reaction tissues and do not mix under any circumstances during circulation.
In Oastanian veins, a flexible membrane seperates chrysós cells and págos cells into 2 channels, this membrane is constantly maintained by vascular cells and is called the diairón.
Each channel has a slightly different density, viscosity and flow speed, in order to create a self-stabilising laminar flow.
Each cell also has a similar surface charge pattern, creating a weak but constant repulsive force that keeps them in their own channels.
The diairón can also shift position slightly, thicken on one side if flow imbalance occurs and repair micro-tears instantly because any mixing could potentially be lethal to the organism.
Respectively, chyrsós cells range from ambers to golds, and págos cells range from cyan to icy blue.
Side note: technically, chrysós and págos can mix during circulation. Over sight on my hand. But, specialised cells, called kaloúpi, are able to immediately detect any mixing through thermal sensitivity and chemical signature detection.
Once triggered, they rush to the sight, and absorb both fuel and oxidiser to neutralise internally. But that does mean they also die in the process.
Due to this method and the urgency for kaloúpi cells, all Oastanian animals have 2 small organs located at the far end of the body that constantly make them and release them into the organism.