Zealandia



Australia is often regarded as the sixth of the seven continents, but in reality there are eight continents. The forgotten continent split off from Australia during the early Jurassic, and has been hosting even more bizarre animals than in Australia ever since. In our timeline it is submerged underwater and is mostly islands, but in Spec Zealandia is a large chunk of land to the side of Australia, and located a little closer to Antarctica. The top section of Zealandia includes New Caledonia, which harbors mainly primitive conifers, like araucaria's. To the south is New Zealand, which has mainly tree ferns.

Once split from Australia in the early Jurassic, Zealandia had fewer therapsids and more non therapsids. Rhynchocephalians were incredibly diverse. In Australia reptiles were represented by lizards, but in Zealandia lizards were non existent. Rhynchocephalians were mainly small, although some larger forms did exist. Some were herbivorous, others were carnivorous, and some even plunged into the waters surrounding Zealandia. New Caledonia experienced higher temperatures in the Jurassic than did New Zealand. Here, dwarf therapsids roamed, mainly cynodonts. At this time, New Caledonia and New Zealand where separated by water, which means both had very different fauna. New Caledonia harbored more anapsid reptiles, like mesosaurs on the coast. Terrestrial fauna was very small indeed, cynodonts didn't even grow to 15 centimeters. The climate was semi arid, with araucaria trees sparsely scattered across the landscape.

New Zealand was different. It was a more elevated landscape, as in it was highly mountainous and had on average more precipitation, and lower temperatures. Here, temnospondyls were even more diverse than in Australia, and rhynchocephalians were the dominant animals. New Zealand had a large array of tree fern forests, and temperatures got low enough to produce snow most of the time. The warming cycle at the end of the Jurassic caused sea levels to rise, flooding more of Zealandia. Rhynchocephalians started to become less diverse, and their population dropped.

At the start of the Cretaceous, sea levels slowly began to drop, but New Caledonia and New Zealand were still separated. When the archosaurs entered Australia, they also entered Zealandia. At the same time, Chiropteramimids from Africa migrated into New Zealand, as it was colder. Archosaurs seemed to have spread into different sections of Zealandia, depending on what type of archosaurs they were. Those with slower metabolic rates, like Suchimorphs and Younginiformes entered New Caledonia. Those with faster metabolic rates, the paramammaliaformes, entered into New Zealand. At this time, apart from the Chiropteramimids, the therapsids were "functionally" extinct in Zealandia. In New Caledonia, dome headed suchimorphs evolved, similar to pachycephalosaurs, but had much longer tails, and five toes instead of three, as well as many other anatomical differences. Predatory suchimorphs would be the equivalent of †Mekosuchus, arboreal, and highly dangerous and aggressive.

New Zealand was much more bizarre. The Chiropteramimids became increasingly diverse. One species, †Anuropterus, became flightless and fed on the weta, a large flightless, nocturnal cricket. Rhynchocephalians became less and less diverse, but their population was only minorly affected. Paramammaliaformes were diverse, and a variety evolved. Some, like †Rodentinia, were hoppers, with a body like an elephant shrew, but with the head of a lizard. A large paramammaliaforme, †Megalatrymimus, even evolved large, somewhat wing like structures, and enormous ear rings, used for display. However, the predators here were more terrifying than anywhere else. †Endocyclaus was reminiscent of a wolverine, but could also run on its hindlimbs. †Bubomimus from Australia, migrated to New Zealand, and evolved more maniraptoran like forms.

The Campanian glaciation had dropped the sea levels in Zealandia slightly. This coincided with the evolution of semi-aquatic and aquatic paramammaliaformes. One evolved, very similar to †Ambulocetus. While some of them were highly adapted to the water, they still needed to go back onto land to lay their eggs. This made many coastal predators, which helped avoid competition with pinnedonts. Younginiformes in New Caledonia also migrated down towards New Zealand, although they didn't interact with the aquatic archosaurs there.

After a short warming cycle, the Maastrichtian glaciation began, which had a profound effect on Zealandia. The sea levels dropped, and New Caledonia and New Zealand were finally joined together. The ice caps reached right into New Zealand, which had a very profound effect on all of Zealandia. New Caledonia was hotter and turned more arid, while New Zealand became much colder, and even Antarctic. Tree ferns and rhynchocephalians were pushed towards New Caledonia as a result. Conifers took their place, and this became a much more complex world. Fossils at this time are not that well known, as the ice cap ended up carrying all the fossils away and when they later melted the fossils were in the deep ocean and likely destroyed. However, in North New Zealand there are still fossils to show that archosaurs had, apart from Chiropteramimids and rhynchocephalians, completely taken over Zealandia. This remained this way into early Cenozoic. More to be added soon...