Sternobrachia



Sternobrachia is an order of faunal organisms within the class Devoratoria that resemble a cross between Earth Fish and Cephalopods. They are active predatory generalists that typically use their advanced sense of smell and developing eyes to hunt and consume any organism small enough to fit into their mouths. They have closed circulatory systems and Hemerythrin in their blood, making it appear pink. Their defining characteristics are:

- 3 chitinous plate-rings to help them hold their form and protect against crushing by other Devorators and stabbing or slicing by prey items.

- A chitinous endoskeletal plate in their tail-fin.

- An orb-eye made of chitin covered by a non-motile lens.

Evolutionary Constraints and Survival Mechanisms
- Devorators rely on brute strength and muscles to kill prey due to the lack of sharp cutting implements, meaning that they must be larger than their prey to hunt it effectively, especially if the prey has a shell or tough exoskseleton. They are not capable of cutting prey up and must use their powerful tentacles to crush it into a small enough size to be eaten.

- Their gills do not have muscles to draw water in and force it out, meaning that they must swim forward constantly to remain alive. Additionally, their intestinal waste is released through the expulsion side of the cavity, meaning that swimming backwards is dangerous.

- Devorators incorporate materials such as mineralised chitin into their chitinous rings from prey items. This means that devorators that prey heavily on shelled or hard-bodied organisms will incorporate their prey's body/shell materials into its chitinous rings, meaning that they will likely have rings made partially out of the aforementioned materials.

- Devorators have specialised adaptations for repelling pathogens and internal parasites, helping them to resist disease.

Biology
Devorators have skin covered in tiny pieces of chitin for defence on the skin between their chitinous rings for added defence. Their non-chitin covered skin is smooth and soft. Their large chitin rings are tough and rigid, functioning as both armour and an exoskeleton that helps the creature hold a solid form. They use their 4 tentacles to kill and/or manipulate prey. Their tail fin contains a large chitinous endoskeletal form to keep it rigid against the sea, as it is the primary method of locomotion for the Devorators, who's bodies are rigid.

Senses
Smell Members of the order use their advanced sense of smell to locate prey and carcasses within the vicinity.

Sight Devorators have relatively advanced eyes with a non-motile lens, which are capable of perceiving both UV and visible light, primarily to locate members of its own species and sight other bioluminescent carpotestans. Their eyes are large chitinous orbs with cones inside. It functions similarly to vertebrate eyes, except that the iris is inflexible, due to being made from chitin. Muscles move the orb around to allow light to enter from different angles. Electroreceptors Devorators have simple electroreceptors that allow them to detect movement between and near their tentacles.

Psychology
Devorators do not communicate with each other but interact through mating and fighting. Members of the same gender that happen to meet will fight until one is dead or flees, whereas opposite sexes will mate. They are not very intelligent compared to advanced Earth life, possessing roughly the same intelligence as an insect.

Organs and internals


Original Devorator Anatomy, with the positions of organs based on a side-view, as well as a front-view at each plate-ring. Devorators possess a number of organ systems:

Digestive tract including:

- Large chitin-plated stomach filled with immobilising acidic gel which is directly attached to a mouth-hole. The stomach contains tentacle shaped projections that push objects out of the stomach that cannot be digested or incorporated into the chitin rings.

- Intestine attached to the end of the gill cavity.

- Enzyme organ to assist in digesting materials such as chitin.

Respiratory and Cardiovascular system including:

- Large gill cavity where water is sucked through gill openings and then ejected through the gill's opposite side.

- Single-chamber ball-shaped heart that pumps Hemerythrin pink-purple blood around the body through simple veins and arteries.

Nerve and Sensory Organs:

- Cerebral ganglion with 3 notochords.

- Eyes with a tissue-based lens. UV and coloured light perception.

- Simple chemoreceptors in the face that are capable of detecting the odour of blood and corpses up to 10m away.

- UV bulbs that release UV light directly ahead that bounces off of reflective items and is then perceived by the eyes, allowing the Devorator to tell what prey it is looking at.

- Ampullae of Lorenzini-like primitive electroreceptors in the tentacles to detect nearby movement between and near the tentacles, with the former being a blindspot.

Primasternobrachidae(Family):
The oldest and most archaic members of the order.

Genus: Primadevoratorus:

- Primadevoratorus Primis (Devorator)