Dicynodontia




 * Class Therapsida
 * Clade Anomodontia
 * Order †Dicynodontomorpha
 * Suborder †Dicynodontia
 * Superfamily †Pylaecephaloidea
 * Family †Stahleckeriidae
 * Family †Cetornithidae
 * Family †Mangeridae
 * Family †Kannemeyeriidae

Dicynodonts first evolved in the Mid Permian, and soon radiated across the world. They were not affected at all by the Permian-Triassic Extinction, and lived on the Triassic. From then on they evolved into a myriad of weird and awesome forms.

The first are the Pylaecephalidae who lived on until the Cretaceous. In the late Triassic, the mustellamimids evolved. These dicynodonts resembled stoats from out timeline, and filled a similar niche, feeding on small archosaurs, insects, and other small vertebrates, including fish, and the eggs of various herbivores and carnivores. These late Triassic forms have long, hair like integument, called tuskfluff, which resulted in an elevated metabolism. This trait was carried on to the rest of mustellemimids. They had long beaks, and their tusks became specialized killing tools. They also underwent a radical change, not seen in any other dicynodont family before it. They started to loose their beaks, and develop teeth inside their mouths. Most are small, the biggest only a metre long. They also filled many niches in many environments. Most were forest dwellers, living in temperate zones. The majority were adapted for life in the trees, so well in fact, that they never touched the ground. Only a few were burrowers. Some nocturnal species lived in deserts, and a few even became aquatic, taking on otter-like forms, and a flattened tail. They were strictly freshwater however. These were the Hydramimines. Many fed on worms and soft bodied animals, but some were adapted for crushing shells and catching fish. Some evolved extremely serpentine shapes, to the point that the arms of one species, †Anurocheirus vagatiensis, lost their digits and became fuzzy stubs, making them fully aquatic and viviparous. The plains mustellemimids are unusual, as they are mainly diurnal, and while they live in burrows, they are huge, the biggest at 1.5 metres long, taking on the roll of midsize predator in the ecosystem. They even made it into Arctic areas, and most were semi-aquatic animals who were only active during the dark winter months, those exceptions did exist. Mustellemimids were oviparous, and laid reptilian like eggs, which, when hatched, were poorly developed and so relied on milky secretions from their mother and fathers skin. †Anurocheirus did not exhibit parental care, and its young were already fully developed when born. Despite their enormous success, mustellemimids began to decline by the early Maastrichtian. With the Maastrichtian Ice Age in its birth, they radiated into the north pole, where the majority of the, were semiaquatic. However, this radiation only lasted for a million years, before the ice age worsened and they began to decline. By the mid Maastrichtian, the last mustellemimmid, †Osklova kienstel, which lived in Siberia, alongside the last gorgonopsid, became extinct, thus ending the Pylaecephalidae's time on Earth.

Marine dicynodonts were another hugely successful group. These dicynodonts are mainly descended from the marine lystrosaurids, who appeared in the early Triassic. These are among the most interesting of all dicynodonts. They are highly adaptable, and have an unusually high range of diet. They are known to scavenge carrion off beaches, and during low tide will dig up clams and eat them. They have palatal teeth that crushes clams. They also eat sea urchins, sand dollars, gastropods, ammonites, sea jellies, sea stars, and sponges. They also are agile enough to catch the fast coastal fish and squid that inhabit the coastal waters of Egypt. They also hunt small sharks and rays. They also feed on horsetails, sea weed, salps, pyrosomes, coral polyps, and sea pens. While mainly coastal animals, when females are left in the burrow to incubate the eggs, the males will go out into the deep ocean and dive for food, including deep sea squid, chimaera's, small eugenodonts, and kilsets, a type of fish related to chimaeras. Once they retune the eggs would have hatched and the males will regurgitate their meals to their pups, before the female leaves to do the same deed. Cannibalism is common among these lystrosaurids. Despite their amazing success, they died out when the first cooling of the Cretaceous began, unable to adapt quick enough. However, several other groups of marine dicynodonts evolved.

The first group of semi aquatic dicynodonts were hippo like stahleckeriidae. Only one specimen has been found, relatively well preserved, but is unnamed. It dates to the mid Triassic of the Chinle Formation. Its body is long with webbed feet, and dense bones, making it three tonnes. It feeds on underwater plants. The second group of aquatic dicynodonts were the cetornithids, and these were more whale-like creatures. Their origins go back even further than the pinnedonts. They first appeared in the early Jurassic, as little burrowing dicynodonts from the Kingoriidae family. As they became more aquatic, their bodies became longer and their limbs shorter, until they developed tail fins to help them swim and lost their hindlimbs. At first, they were largely herbivorous, feeding on kelp, but then sprang out across the oceans, and many took on a planktivorous diet and piscivorous diets. Some, like †Walwala korgiech, were the apex predators of the coast, similar to orcas, and fed mainly on pinnedonts. The group were not affected by the end Mesozoic extinction, but became extinct for reasons unknown by the mid Oligocene.

Dicynodonts on land were not all small. As the temperate forests spread in the Jurassic, many took on to become huge, like the Mangeridae. These forest dwelling dicynodonts were more slender in build, having long necks and legs, and became almost elephant like. One group, Willowsuckers, evolved their tusks to remove tree bark, and evolved a long tongue to lick up colonial insects. However the majority were herbivores, feeding on the tops of trees. Their tusks where small, and they had enormous tongues to help pull vegetation into their mouths. This made them the sauropods of the Mesozoic. They thrived until the end of the Jurassic and clung on in remote areas, mostly mountainous terrain until the mid Early Cretaceous. <p style="font-family:Times New Roman;"><span style="font-size:16px;color:black(255,105,180);">Other terrestrial dicynodonts, like the Jurassic Kannemeyeriidae, grew armour under their skin, like pareiasaurs, for protection. However, as gorgonopsids evolved armour crushing teeth, they evolved external armour, with the most heavily armoured genus being †Porochelys of China. They also reached enormous sizes, the biggest being the biggest terrestrial dicynodont known. That was †Geyamorphus, a four meter long and 6.5 tonne Kannemeyeriidae from the late Jurassic of Scotland.

<p style="font-family:Times New Roman;"><span style="font-size:16px;color:black(255,105,180);">The majority of the terrestrial dicynodonts were like those in our timeline, but as time went on they got bigger, and bigger, and were all herbivorous. The only carnivorous dicynodonts were the mustellemimids and the marine dicynodonts. As time went on, the dicynodont radiation collapsed on land, and they nearly became extinct in the early Eocene. By the late Oligocene, the terrestrial dicynodonts became extinct.