Lesser Sideray

All along the northern shorelines of tropical Miesjeta, you can find a most peculiar looking creature swimming through the sand. From a glance it resembles a Batomorph from Earth, better known as a ray, but the resemblance is only superficial.

Upon closer inspection the differences become more apparent. One anatomical trait that instantly determines this animal to not be a Batomorph is the fact it has gills on its "upper side". To those less knowledgeable on the anatomy of Batomorphs, there is another trait this Eryobian animal possesses that should make it clear that this no true ray.

The creature has but a singular eye on its entire body, adorned with a pupil possessing three prongs to form a "Y" shape. No vertebrate animal from Earth is known to naturally have such a trait. For this reason, many researchers refer to these ray like creatures as cyclopses. Unfortunately for them, the scientific name of Cylopoida is already taken by a group of copepod crustaceans from Earth. Instead, a name that is often used in addition to cyclops is sideray. There are also many researchers who prefer to refer to these creatures by their scientific name solely, as Monobatopsids.

Further research revealed Monobatopsids to actually not only be related to nienktvissen, but that they are actually very derived members of this group. In hindisight, it should have been quite obvious that siderays are nienktvissen. They share some key characteristics such as the lack of jaws, but presence of well developed plate like tooth elements. The six individual gillslits should also have been a dead giveaway since no other non-conodont animal on Eryobis possesses this trait. The presence of a number of barbels sprouting from the lips is also a strong indicator of their identity as nienktvissen.

So it became clear that cylopses are merely nienktvissen that opted for a demersal lifestyle by laying on their sides, but they are not born this way.

When siderays hatch from their eggs, they are extremely small and are virtually indistinguishable from other, related nienktvis larvae. For their first weeks of life, they develop much like other nienktvissen, gaining their characteristic large fins to propel themselves with and this stage, they possess two eyes, one on each side of the body.

But as they mature, they start changing. They start living closer to the seafloor and begin favoring one side over the other. Whether this is left or right usually differs per species or subfamily. They start living near the substrate and will instinctively hide in the sand. It is at this stage that the eye on the side that faces the seafloor starts atrophying until it is completely resorbed into the body.

Why this happens instead of the migration of the eye like is seen in Pleuronectiformes and Planosolincolans is unclear. One would be forgiven for thinking that the entirely cartilage "skulls" of nienktvissen would make such a migration easier than if the skull was bone.

One of the first aquatic animals to ever be encountered on Eryobis by explorers was the lesser sideray (Rajacyclops minor). This creature can commonly seen inhabiting the shallow coastal waters all along the northern coast of Bloëcan Miesjeta, which is ofcourse where the first landing site and colony were made.

It is a small critter, barely two hands wide and only a few centimeters thick. This makes it perfectly adapted for a life in the sand in waters where few predators can reach it.

Yet this little cyclops is often the largest predator in its sandy environment. It feeds on a plethora of invertebrates such as gastropods, sedentary bivalves, pectinauts, brachiopods and small llamplelgans. 

As with many sideray species, the lesser sideray possesses a three pronged pupil in its singular eye. It is thought that this peculiar shape helps siderays see from multiple angles. An imperative ability for an animal that spends most of its time hidden in the sand.