I did not see that written content was not allowed on the subreddit in regards to this, so I registered here to submit the entry proper.

The many radiations of mussel munchers:

With some competitors out of the way, mussel munchers became common in many coastal communities. But it was only a matter of time before strange, new forms would appear.

Some would develop live birth and dive deeper and deeper for food, feeding on more than just molluscs, but various fish and other smaller animals as well. They would also begin to head further and further north, as well. Some would start moving back inland and take on various forms of large animals. However, due to competition with much larger relatives, this primarily occurred on smaller landmasses.

On one landmass, due to a lack of competition, they would begin to move inland, once more, and start taking up various niches formerly held there by various animals.

Tusked Glutton - A species of dicynodont that grew huge, they are entirely aquatic and feed primarily on various aquatic animals. They will not even hesitate to snag up things like the few whales that exist here, being extremely greedy when it comes to food. When feeding, they use their powerful jaws to simply shear prey in half, and scarf down the remains. They primarily patrol the open oceans around Edmonstonia, but make large migratory treks to Murilandia's coastal waters every year or so to calve. Despite their nature, they seem to exhibit some level of parental care for offspring, compared to a lot of other dicynodonts. They reach a length of 8.3 meters, and have a somewhat sleek, torpedo-like body with numerous raised bumps. Unlike their ancestors, they do not have a trunk, but do have a pair of upwards facing nostrils. They are known for loud, guttural calls that can be heard for kilometers. Their body is heavily counter-shaded, as to hide from both larger animals and to gain the upper hand on smaller animals.

Spear-snouted Glutton - A smaller species of Glutton, these small reptiles have black and white hourglass-like patterns throughout their entire body, with mottling here and there. Patterns are unique between individuals, and can be used to identify said individuals. While normally solitary, if given the chance, they will take on the role of a opportunistic predator, cuing to others nearby to begin feeding, but otherwise, they primarily feed on the various mollusc-based reefs present, and are often found near the reefs and atolls around Edmonstonia's southern shore. They reach a length of 2.3 meters. They are one of the primitive-most species of glutton, as unlike the tusked glutton, they have two pairs of fins, with one main pair in the front of their body, and a smaller pair in the back that are more like reduced legs.

Pygmy Muncher - One of several oddball species that went further inland to Edmonstonia, this species began to specialize on eating various plants once more, straying away from its traditional diet of molluscs. Due to the size of the landmass however, it shrunk heavily in size, but still towers over many native animals. Unlike the gluttons, they still lay eggs, as opposed to giving live birth. Of note is that it has a fairly armored body, with scute-like structures dominating their entire body, making it harder for larger animals to attack them. They reach a length of 2.1 meters long. Their noses have become heavily reduced, for a trunk-like condition is no longer needed on land.

Spined Terror - A rather large predator found inland, while still dwarfed by their coastal and aquatic cousins, they have become a dominant predator in Edmonstonia, becoming reaching a length of 3.4 meters, and as they share a common ancestor with the Pygmy Muncher, they would develop scute-like growths, but on top of this, they developed various forms of horny ornamentation on their head, which, while found in both sexes, is much more pronounced in males. They also have two spikes, one on each shoulder. Their noses have become heavily reduced, for a trunk-like condition is no longer needed on land. Unlike many secondarily-terrestrial munchers, they retained their carnivorous habits, and directed them towards preying on any organism smaller than themselves. However, they cannot be classed as true hypercarnivores, as they will still supplement their diet with a substantial amount of plant matter.

Bahamut - An extremely massive muncher, this species is native primarily to Edmonstonia and Wallacea, and are known for having males with absurdly large sizes, reaching up to 7.4 meters long in this case at the absolute max. Like all amphibious munchers, it comes onto land to lay eggs, but before it is remotely time to begin egg laying, males engaging in epic battles on the coasts, and will roar and bellow at each other, slamming their massive bodies into one another, rearing the tusks as well, in an attempt to stab one another's rather fatty body. Whoever tires out first is driven off by the more successful male, and said successful male proceeds to mate with as many females as possible, unless a stronger rival comes along. Their diet consists of various fish, molluscs, squids, rays, and sometimes, some gluttons and munchers and some avians, slicing them all in half with their powerful beak. Their body, as mentioned above, is covered in blubber, and their limbs have turned into seal-like flippers. Their noses have become larger, but solely to use in threat displays, and to amplify their calls.

Selkie - A much smaller amphibious species, like it's larger relative, the Bahamut, it has specialized heavily into the ocean, and usually only comes on land to mate. Compared to it's relative though, it is far less aggressive, but can still be just as insidious, as they will sometimes prey on bahamut eggs. Eggs do not comprise their diet though, and their diet is fairly similar to their relative, but they rarely attack terrestrial organisms for food except out of desperation. They reach a length of 4.3 meters long. Their trunk is reduced, but still present. Their tusks, meanwhile, have completely atrophied. Like their relative, they have a blubbery body. They are found in Edmonstonia, Wallacea, and Maathalia. Compared to their relative, they are far more monogamous, and live in small family units comprised of one male, one female, and their pups.

Snout Rat - A really small species of dicynodont, like many of the mussel munchers of Edmonstonia, it is secondarily terrestrial, and moved onto land in light of many vacant niches. While the trunk has become reduced, it is still present, and is far more muscular than many of it's relatives. This trunk, along with their powerful arms, are used to dig massive tunnels, in which they reside in. The trunk allows them to get air without having to fully leave their nest, and also plays a part in clearing obstacles for the tunnel. They feed primarily on various insects, and will rip apart logs to eat the insects hiding inside. They will also take in various tuberous vegetables found underground. Reaching around 0.26 meters long, they are one of the smallest dicynodonts found on Edmonstonia. Unlike many of the secondarily terrestrial dicynodonts of Edmonstonia, it gives live birth, and has litter sizes of 2 - 5 pups.

Common Bee-Eater - With the diversity of hymenoptera found on Edmonstonia, one species would specialize entirely in preying on them. This species reaches a length of 1.35 meters long, and unlike many terrestrial dicynodonts, lacks any tusks. However, it does not need tusks, as its front limbs are heavily muscular and terminate in very long claws. They use this to rip open logs for food. On top of this, they have an extremely long tongue, which they use to siphon hymenopterans out of hiding. Their snout has become slimmer, in comparison to their ancestor, to help reach into hard to reach areas. They are one of the few animals that can challenge Spined Terrors, as usually a swipe from their massive claws is enough to make them back down. They share a common ancestor with the Snout Rat, but unlike them, they lay eggs.

Barrel-Gut - Another large dicynodont, they reach a length of 2.7 meters long, and feed primarily on foliage. Their bodies are known for an unusual barrel-like shape, and a large amount of scute-like structures covering them. Males have unusually large tusks, even for their size. They are fairly social, moving in herds to avoid being attacked by Spined Terrors or territorial Bee-Eaters. These herds usually consist of females and their young, as males are extremely aggressive and only stay with a female solely to mate, and then leave. Barrel-Guts have been known to attack Selkies, Spined Terrors, and Bahamuts, seemingly with no provocation. Males are also known to fight with Common Bee-Eaters, but the long claws of the Bee-Eater are able to leave permanent scars on their faces, or even blind them. It is believed this behavior is territorial, as most of the time, males will only fight against other males. Of note is that they are known dispersers of unberribles, as they seem to have developed a tolerance to the caustic sap and freely eat the fruit, or climb on the plants briefly, knocking many fruit off.

Hook-Nails - Another small but somewhat specialist dicynodont, they reach a length of 0.22 meters long. They are arboreal, and have rather long and hooked claws that ensure they stay attached to a tree. They are capable of somewhat jumping from tree to tree, but it is nowhere as complex as a primate, and usually only happens if disturbed by something, as otherwise, they stay on a specific tree for quite some time. They feed primarily on fruit and leaves, but will also sometimes take some insects. They are known for being skittish, and flee upon seeing large wildlife of any kind.