New mini series is starting. I love marine biology so I think it would be fun to look at (in a bit too much detail) all the features which the marine creatures in sonaria have, and potential reasons for these!
So let's start with Kohikii,
Kohikii is a mix of Bobbit worm, Spotfin Lionfish and Horror-Film Worms. Kohikii has a pair of Bobbit-Worm pincers, two antenna appendages on its head and shorter antenna stemming from its Maxilar. presents with Triple Dorsal fins, two pectoral fins, smaller pelvic fins, spiny anal fin, small-finley protrusions, a 3-finned homocercal caudal vertical tail and bioluminescent diamonds with plate-like details covering their body.
Now, let's start with the parts, which i have tried to label as accurately as i can
The antennae were especially confusing as the Antennules appears to be both Flagellate and Segmented, a flagellate antennules have muscle attachments at the base which act as a hinge for the flagellum which is a flexible string of annuli which are not connected via muscle and a Segmented Antennules is when the Annuli are separated from other Annuli by an individual muscle attachment.
When looking at Kohikii’s antennules, they appear to have a hinge at the base, but are also segmented, upon looking at swimming animations on the page the muscle hinge does not move the antennules and they move in a way which would make them segmented, which makes me believe Kohikiis antennules are in fact segmented and do not need the hinge at the base of them. The rest of Kohikiis antennae appear to be Flagellate as they are not segmented at all but simply have bioluminescent ends and do not appear to move on the animations.
I have no issues or questions about any of the fins. Although i find the description of the tail being Homocercal to be quite interesting, a homocercal fin, definition is as follows “the fin usually appears superficially symmetric but in fact the vertebrae extend for a very short distance into the upper lobe of the fin.” The tail being Homocercal would not make sense for Kohikii as it would appear that the Vertebrae extend very high into both the upper and lower lobe, although homocercal does make sense in the “symmetric” sense, the vertebrae does not but it is the most accurate definition of Kohikiis caudal fin.
So, let's move onto the next section of Kohikii,

Although the description for kohikii does say that it does not have a lot of defence and only has a few plates, i have marked what i believe would be, or is plated sections of the kohikii, these plates would likely be under the skin and centered more around the face, mandibles and back (as far as i can tell from the reference) and then in the antennae. Although plating or shells are primarily seen as a defensive evolutionary trait, seen in things like Armadillos, turtles and Pangolins. Plates are not just for defensive purposes, an old example of this being the Dunkleosteus, the Dunkleosteus was an Apex Predator during the Devonian Period, its teeth and head were made of plates which it used to catch its prey, they were not for defence, but more for attacking/avoiding injury, similar to this, i believe that Kohikiis head, mandibles and antennae would be plated to avoid injury or damage while it hunts, especially to the antennae as it is completely blind and has to use them to sense its surroundings.
As for the bioluminescence, I find it interesting that Kohikiis apparently lower the brightness of their bioluminescence when hunting, which means kohikiis have Non-Visual photoreception meaning they can sense light levels without the need for eyes. Although it is surprising they would lower bioluminescence considering that in other sea creatures, bioluminescence is used to hunt, seen in Angler fish, some cuttlefish and specifically cookie-cutter sharks which attract things like squid using bioluminescence on their stomachs to then grab them. The bioluminescence on Kohikiis mandibles and teeth would likely be used in a similar way, to attract prey towards it, and suddenly grab them with the mandibles.
Now to move onto the last and arguably largest section, the rough biology of the anatomy of Kohikii
I will be going through this in colour order. (i meant to put Chitin instead of Keratin)
So, let's start with the cartilage and keratin of the Kohikii, kohikii would have to have cartilage in each fin and especially around the face and jaws, the antennules would be made up of a Chitin shell, like that of crustaceans and its spines be made of Chitin as well, however if we are specific to the fact that kohikii are partially based on Lionfish, then they would actually be made of a mineralised collagen-like material, however the spines on a lionfish are specialised to inject toxins which is why i believe they are more likely to be made of Chitin. Spines are usually made of bone or modified scales on fish, so on a kohikii it is likely to be made of modified scales.
red muscle is used for sustained, slow swimming and is rich in oxygen and mitochondria meaning it produces a lot of energy, white muscle is used for fast bursts of speed and pink muscle is an intermediate between the two, used for moderate swimming and sustaining fast swimming speeds. Kohikii is described as being a quick and speedy killer, meaning it likely has a large mass of white muscle, around its tails and main body, while still having red muscles, especially around the mandibles, jaw and front of the body.
The organs on a kohikii would likely be found closer to the front of the body (the larger, main organs anyway) like liver and stomach. What i find interesting is that kohikii is described as having a very fast metabolism, in nature, the lager the creature, the lower the metabolic rate, however for kohikii it is different, they are quite large creatures and yet have a high metabolic rate which could be caused by a number of things, these being how active a creature is, endothermy (keeping the body at a certain temperature), oxygen delivery, environment, and evolutionary trade-offs. Seeing as though kohikii is also described as having a bit of an insatiable hunger then they would be quite an active creature which could explain the high metabolic rate, but it does appear that the hunger is caused by the metabolic rate rather than the other way around. Endothermy could be another factor, kohikii could require itself to keep a specific internal body temperature which would require a lot of energy to maintain, it could also be due to kohikiis environment (however i do not know much of its environment and can only make assumptions). Meaning it is likely an evolutionary trade off, to be fast, strong and deadly, but require a lot of energy leading to high metabolism.
I believe that just about covers everything there is about kohikii, I am by no means an expert on this and a lot of this is personal opinions with research into existing sea life.
This was just a silly project that took me two days to complete, not sure which aquatic i will do next