Square-Headed Dignathophagus

Dignathophagus comewaii is a species of Dignathoid Armadillodorsaloid amphibian from the arctic waters under the Ice sheet.
The animal can be commonly found in units from one to three of the ice sheets but it was also sighted in units four to six, although much more sparsely; as the light gets dimmer the more you approach the mouth of the underworld, the rarer the animal gets in favour of other Dignathoids.
The species feeds on smaller amphibians such as Cinerichthyds and Esavelids but will also use the inner dentition to scrape off of the Icy ceiling invertebrates and other small animals hiding in upside down forests; another main component of the animal's diet is composed by carrion, which they can easily break down in group using the inner jaw.
Usually found in medium-sized schools of a few dozen specimens, the animals will insulate by staying very close together and, like most other cold water amphibians, using the third skin layer to agitate and heat the water of the second layer to create an artificial coat.
The peculiar inner dentition grows on a mobile gum which can extend outwards and be used by the animal to grab prey and drag it towards the Sphaera Lania, making the ingestion process faster, especially useful when scavenging as it's often just a matter of time before something larger comes by to claim it in their stead.
The slim body and modest size allow the animal to seek shelter in crevasses among the ice ceiling, where most predators wouldn't be able to reach them.
When threatened and with nowhere to run, the species will employ a second tactic to defend itself by showing the fully extended gum: Extending outward and sideways the gum the animal makes its mouth look much bigger than itself in what is often referred to as a "grin", possibly spooking predators for the time needed for the group to escape.
As more and more fishing companies of the northern shores turn their heads to the arctic waters, the future of this species looks uncertain; overfishing of the smaller species of Esavelids coupled with private Cinerichthyd extermination projects are the main cause of this species' decline in the first units of the Ice sheet, where trawlers can still break through.
Although not edible, the peculiar inner dentition of this and other animals of the family is a partial reason why they're fished and killed to be sold in the international trade.
Although these activities might seem to spell doom to the animal, in many areas, especially around scientific outposts, fishing activities are forbidden, creating safe havens for the animal; the largest reserve to date is around Precursor's Hearth in the Oliben Complex where, under Deshivohai jurisdiction, it is forbidden to alter the environment.

Basic Information

Anatomy

• Head square shaped, inner dentition can extrude outside the mouth's natural reach.


• Maxillo-massenteric plate square shaped, attaching to the Fronto-temporal plate above the eye level.


• Presence of a Lacrimo-parietal plate segmented from the Fronto-temporal.


• Postcranial armour composed by two very large dorsal plates and four small pseudo-aculei at the base of the dorsal fin.


• Dorsal plate II triangular in shape, if seen from a dorsal view.


• Armour briefly opens up above the Sexual Hoplos.


• Pectoral fins very reduced, characterized by a cartilagineous pseudo-digit.


• Dorsal fin veiled and subtriangular.


• Anal fins long and thin, spear shaped.


• Gill Tail and Gill Fan connected to the body seamlessly, reducing heat dispertion.

Genetics and Reproduction

Promiscuous species.
D. comewaii mates in the early summer but the exact mating period seems to change slightly the deeper you go into the units of the Ice sheet, possibly due to changes in light intensity and food availability.
The various members of the shoal will mate with several different partners to ensure the highest possible spread of the genes in the group is achieved.
Although there's still quite a degree of uncertainty on how the mates are selected or if it even exists an internal hierarchy to begin with, it is known that the species lays the eggs in communal nests along with two or three other shoals, caring for the eggs cooperatively.
The eggs are laid in ceiling flats in single rows suspended in the water by long mucous filaments, creating egg braids usually called "Bead curtains".
The construction of said nesting sites is equally divided between males and females: -The males will excrete the specialized mucous from the parapenis, manoeuvring it with precision to follow closely the female as she lays her eggs as to catch them the moment they're out of the duct, enveloping them in the string -The female will lay the eggs at regular intervals, adjusting the water levels and position in the second layer to sink vertically and regaining buoyancy.
The communal nest will be kept clean from scavengers and other pests by the entire colony until the eggs hatch.
The various schools will distribute the young between themselves and disband; it's not uncommon for some specimens to switch communities during these events.

Growth Rate & Stages

Ontogenesis in the species not incredibly marked.
Young specimens are born with a fused fronto-temporal plate and no opening atop the Sexual Hoplos.
Loss of natal aculeus along the top section of the armour, which detaches as a whole in what is known as the natal plate.

Ecology and Habitats

Epipelagic species found living under the ice sheet at depths not superior to 100 m.
Lives right under the Ice ceiling, in areas with a moderate amount of vegetation and plenty of crevasses in which they can find shelter.

Dietary Needs and Habits

Carnivorous species feeding on a large array of small amphibians and invertebrates.
Its diet is also composed by carrion they injest as quickly as possible before other bigger animals come by.

Biological Cycle

Seasonal species entering a state of reduced activity in Autumn and Winter.

Additional Information

Social Structure

Social animal living in moderately sized groups.
It will congregate in larger communities during the mating season, where they'll care for the communal nest and eggs until they hatch.

Domestication

Although not impossible to domesticate, the species is not kept in captivity due to the difficulty to extract safely the animal from its native habitat.

Uses, Products & Exploitation

Of no use to human activities outside of a small market for the inner dentition as a souvenir.
Populations in decline due to human overfishing of prey species and extermination campaigns of cinerichthyds.

Geographic Origin and Distribution

Units from one to three of the external Ice sheet, becomes rarer beyond unit four, although its still seldomly sighted.

Perception and Sensory Capabilities

Adeguate eyesight, good hearing.

Symbiotic and Parasitic organisms

None known.

Scientific Name

Eoichthyia; Armadilloarmatia; Armadillodorsaloidea; Dignathoidae; Dignathophagus; D. comewaii

Lifespan

13 Years

Conservation Status

Vulnerable: No measures underway to protect the species.
Population Trend: DECLINE

Average Weight

400 gr to 4.6 kg

Average Length

30 cm (male) , 45 cm (female)

Body Tint, Colouring and Marking

Blue to teal body, lighter armour.
Single purple band along the middle point of the body, same colour seen in the four pseudo-aculei at the base of the dorsal fin.
Purple gums.