Concavotheria

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

## Evolution and taxonomy

Concavotherians are the basalmost spinodontians. Spinodontians are a derived clade of spinocaputians, the so called "jawed crucissymbioticans". These are more derived for having more plasticity in their proboscis arrangement. Spinodontians first evolved in the Scelusian, 171 million years ago. Concavotherians themselves represent a basal branch whose modern members diverged from each other in the late Scelusian, 161 million years ago. Concavotheria is the sister clade to megadontians, which differs from concavotherians for having a lower jaw made out of the central proboscis, while the concavotherians have jaws made out of the lateral proboscis. Megadontians have evolved after the Scelusian-Variagene extinction event, with the first ones having evolved 123 million years ago.

Spinodontia (171-0)

* Concavotheria (161-0)
	+ Concavoculus
	+ Delgutitotherium
* Megadontia (123-0)

## Characteristics

Concavotherians have various basal and derived characteristics that make them unique creatures in their environment. The basal concavothere had semi-fused three proboscis with hardened tips, useful to grab prey. However the gradual evolution of these went to radical changes. The evolution of their jaws is believed to have been simillar to that of the even more derived, but more basal, alcyoneucaputians. The Concavoculus clade is known for having primitive extinct members, dating back to the end of the Scelusian, close to the origin of the concavotherians. They shared many characteristics that point to how the evolution of their mouths occured. Fused three proboscis had three armoured tips to grab prey. These proboscis eventually ramified into three longer tips, attached to the base of the proboscis that branched into a long string. This is found in primitive concavoculians, such as the parasitic oculosangiroids, where the three "jaw parts" are attached to long strings of proboscis. The more derived concavoculians have lost these branched proboscis strings in favour of keeping a large "beak", each part belonging to a proboscis, and the feeding orifice being found at the base of these. Delgutitotherium diverged earlier, but shares simillar evolutionary achievements. It has long string-like proboscis, with each lateral proboscis attached to a large armored plate that works like a jaw... different result from the jaw evolution of concavoculians, but certainly derived from the same original proccess. To aid in the motion of their jaws, the concavotheres evolved cartilaginous rods to help move them. The evolution of the eyes is particularly unique. The first concavothere had what is known as a "interconnected ocular organ", a procces that allowed the compound eyes to merge under the skin and into various different chambers. The first concavoculian is known to have had three chambers for the eyes to fuse underneath the skin, which resulted in the formation of three ocular openings. Some concavoculians eventually lost those, like the basal oculusangiroids, with only one opening for the fused eye, but most retained them and kept the three openings. Delgutitotherium has the interconnected ocular organ way weirder. The two compound eyes are just partially fused under the skin, but have eventually morphed and protruded into four openings, making Delgutitotherium, essentially, a four eyed creature. Their orifices are also differently placed. All concavotheres retain olfactory orifices at the tip of their rostrum. In advanced concavoculians, they have attached to the base of the upper jaw, which is now fused with the rostrum. The respiratory orifices have also migrated and changed arrangements. Initially migrating to the front of the body, with the orifices closer to the rear being more atrophied, as seen in Delgutitotherium. However modern concavoculians have one major orifice at the front and five to three breathing orifices further behind the body and more oriented to the top of the body, allowing the evolution of some benthic-based species. The presence of external armor is also variable. Delgutitotherium has an armored rostrum and its dorso is filled with external bony armor that is formed randomly across the skin, which forms unique patterns for the identification of each individual. Concavoculians basally have four segments of dorsal armor, but some eventually lost them all, for streamlining movements, like the oculusangiroids, while more advanced concavoculians retained the four segments or lost one of them. The basal concavotheres have evolved large flippers for underwater motion, instead of perfecting their tail fins. Although the largest and basalmost concavoculians have a tail fluke, Delgutitotherium and benthic concavoculians do not and rely on their wide flippers for underwater motion, like a ray or a plesiosaur. Basally concavotheres have eight limbs, but many eventually lost the use of the atrophied last pair of limbs, being the largest concavoculian the only one that still retains that last pair of limbs. They have a cartilaginous skeleton, including the skull, just like every crucissymbiotican. The only ossified part of its endoskeleton is the bony supports on their limbs that stabilize the large muscular flippers.

Concavotheres are one of the largest oceanic predators of Wallace II, only surpassed by a few carnivorous gomphiobians in length. The largest concavoculian is *Oculocean* *rostrum*, that has a maximum length of 20 meters, making this one of the apex predators of the world's oceans. Delgutitotherium, is smaller, but still pretty big for a predator, measuring six meters in length.

## Distribution and habitat

Concavotheres are found in every oceanic water of the globe, no matter how cold, no matter how warm. They are perfectly adaptable to be one of the most notable oceanic predators of the globe, wielding a title only gomphiobians did before their inception. Delgutitotherium is found in every ocean of the world as a formidable predator. Concavoculians are also found in every ocean of the world. A few benthic species prefer shallower waters and they are often observed visiting brackish and swampy waters.

## Diet

All concavotheres are carnivorous. They all use their hyper specialized "jaws" and sharp proboscis to grib and crunch prey. The basal concavoculian oculusangiroids are parasites, though, as they feed on bodily fluids from hosts, such as blood.

## Behaviour and sociality

Concavotheres are largely solitary, but in occasion they are seen hanging out in small groups. They practice echolocation, by clapping their jaws quickly as a form of creating vibrations to find their surroundings. This way they are able to detect things in the darkest depths and nights or in the murkiest waters, and dictates their good sense of hearing. Concavotheres good sense of hearing is not far from the level of its good sense of smell, but its sight is a bit less sensitive in dark and murky waters, as they require good amounts of light to let their eyes guide them. They are however very good at distinguishing color.

## Reproduction

Concavotheres perform interesting sexual displays. They have a very good color vision and they actually rely on color to determine and classify a potential mate. Delgutitotherium males extend their proboscis strings that display a vibrant color, in an attempt to impress the female. Concavoculians also perform a simillar strategy, though for those that do not have stringy proboscis, just opening their jaws to show their vibrant oral interior is enough, which gets particularly vibrant in males during the mating season. Once the female accepts the male, the female will lay her eggs in shallow waters, where the male will proceed to fertilize them. The eggs are not taken care by the parents, and the babies hatch completely independent, spending the first moments of their life in shallow waters, before being able to go to the deeper and/or more open waters their parents frequently visit. The lifespan of concavotheres can be long. The largest concavoculian can reach a lifespan of 65 wallacian years.