Oseodontida

**Oseodontids** are a clade of celernantids that are alive today.

## Evolution and taxonomy

Oseodontids are a sister clade to Venenumaxima, together being part of the Pedescephalia clade. The pedescephalians originated 201 million years ago, in the early Scelusian. This clade is different from other relatives, like oculians, brevralexians, sporafiliians and patellajulians, for being able to lay their eggs in which the babies hatch already capable of air-breathing. Oseodontids themselves are basal pedescephalians that only diverged from each other 134 million years ago in the Variagene, after the Scelusian-Variagene extinction event, where they start their first tries at developing jaws. Boxhead's very complicated jaw morphology demonstrates its basality to the oseophaethontians, that first evolved 67 million years ago in the Compsogene, native to Media Insula, today. Their jaw morphology is based on hardened proboscis, unlike the hyoid jaws of patelladromeans.

Just like every celeramontian, the oseodontids were once believed to be ambulospeculids, until genetic analysis confirms they are celernantids instead.

Pedescephalia (201-0)

* Oseodontida (134-0)
	+ Boxhead
	+ Oseophaethontia (67-0)
		- Leophaethon
		- Oseodonta
* Venenumaxima (176-0)

## Characteristics

Oseodontids are usually distinguished from venenumaximans for having "jaws". The arrangement of these jaws depends with the species. Boxhead's mouth is likely the oddest and most derived. Its mouth is divided in three armored plates that open. The two lower armored parts are attached to relatively weak "hyoid" jaws. The upper plate is attached to the central proboscis which is highly modified. Two armored and articulated branches start to diverge from the main proboscis, that are used to grab pieces of flesh into the main mouth. As the mouth opens, two long proboscises with serrated bony tips slice the flesh of the prey. The food is swallowed and consumed by the main oral orifice at the base and center of the mouth, no longer using the proboscises themselves to feed. Oseophaethontians lack this complicated mouth arrangement. Instead the central proboscis is a tubular "tongue" that consumes the food, and the two proboscis have become covered in a hardened exterior and turned into two lower jaws to proccess food. Leophaethon jaws are fused together by flesh, but oseodontans have their jaws separated or semi-separated. The compound eyes of oseodontans are traditional-looking, with the exception of oseodontans that have more complex eyes with pupils to better focus their preys or predators. Oseodontans and the boxhead had many armour covering its body for protection. Leophaethon, in contrast only has a row of spikes in the dorso and neck to protect itself, conserving its speed and agility. All oseodontids have eight limbs. Boxhead is octopedal, walking on its full eight limbs. Oseodontans walk on six limbs, with the frontal pair evolving into pincers. Leophaethon is quadrupedal, with the central pair of limbs being atrophied, yet articulated to grab and drag prey. Their respiratory system is characterized by a unified lung, evolved from the chain lungs of the basal viridimaximans, as seen in sporafiliians, for example. Oseodontid lungs connect all the spiracles. Oseophaethontian complex spiracle net allows the formation of eight "vocal cords" that allow them to create complex sounds and calls, allowing for efficient communication between different members.

Oseodontids have a limited variation in size. Oseodontans are the most diverse, ranging from 1,5 meters to 3 meters in length, the smallest oseodontids belonging to this clade. Leophaethon can reach large lengths of 2-4 meters in length, making them one of the largest

## Distribution and habitat

Oseodontids are very diverse and abundant in Media Insula, with Leophaethon dominating the forests and savannas of the continent as formidable predators. The oseodontans are very diverse and are encountered in a myriad od Media Insulan ecosystems, avoiding the too arid deserts, though. Outside of Media Insula, only the boxhead exists, in the secluded forests of Occidentis, also, as a formidable predator.

## Diet

Most oseodontids are carnivores, however oseodontans display its fair share of omnivorous and herbivorous species. *Cristatus* is a sidobosivore, hunting sidobosians by preference. *Lignumexuge* is a herbivore, using its pointy rostrum to perforate polyspeculates and feed on its sap. Leophaethon uses its powerful jaws to crush bones and flesh, dictating its hyper carnivorous lifestyle. Boxheads hunt large prey, despite being shorter than a man. Its long serrated proboscis dictate fierce wounds and even venom is injected to make the kill easier. Eventually the boxhead may follow the weak and wounded prey until it succumbs to its fate.

## Behaviour, sociality and intelligence

Oseodontids are largely solitary creatures, defending their space of territory. The difference might be in the plain living and large species of Leophaethon, which hunt in packs. This allows them to hunt down prey larger than themselves, like the giant sustansurisups. Other smaller species of Leophaethon, live in jungles and are solitary. The intelligence of oseodontids is particularly advanced. When comparing the intelligence of the boxhead, it has been discovered they are at the same level to a dog or a wolf.

## Reproduction

The reproduction habits of oseodontids are rather interesting. Some species are decently colorful as males. The oseodontan *Cristatus* has a blue and yellow crest behind the head and a tail fan with the same colour. These are used to attract females, whose colors are more dull. The tip of the "proboscis snout" of the boxhead is also of a colorful red in males. Their sexual intercourse is made back to back, due to the way their reproductive organs are arranged. Unlike more basal terrestrial celernantids, like the oculians, brevralexians, sporafiliians and patellajulians, they do not need to lay their eggs in moist or watery environments. Females differ from the males for having a special chamber where the eggs are laid there. There the eggs are developed away from the hazards of the outside. Its not exactly ovoviviparity, though one can argue their eggs are laid in a "pouch", of sorts, like a marsupial. Oseodontids perform external fertilization, which is somewhat what happens with other basal viridimaximans, like with brevralexians and oculians, though some sporafiliian females instead store the male's sperm to later fertilize the eggs they have laid after. With oseodontids, the eggs in the pouch are fertilized by the male and then they will incubate in the female's pouch. Once they hatch, thet babies will grab themselves to special glands that secrete nutritious fluid that feeds the babies, but often there's not enough glands for every chck, and if there's too many, the chicks that got nothing, will die, and are food for the survivors. They will then exit the pouch when they are able to walk, and from then they will fend and live their life for themselves, and the mother will no longer pursue parental care after that.