Biogeography

The biogeography of *The New Dinosaurs* is explained throughly here. Biogeography is, essentially, the distribution of species in their ecosystems across the globe. There are multiple categories of biogeography, but in this speculative evolution project, the major focus is **zoobiogeography**, the distribution of animals in their ecosystems across the globe.

There are several zoogeographic realms here, which consist of...

* Americas (North and South America)
* Oriental (Australasia and some parts of Asia)
* Eurasia (Most parts of Asia and Europe)
* Polar (Antarctica and the Arctic)

## The Americas

Regarding events such as the Great Biotic Interchange, the evolution of various creatures of the Americas is driven by the isolation, diversification and weather patterns of the two connected continents.

### North America

North America is distinguished by its separated seasons and differing terrain. There are deserts, plains, forests and mountainous areas. Here, there are large tyrannosaurs, species like the Californian beach-comber or the sail-backed spixus. A common sight are ornithopods; like the ceratopsids roaming throughout the continent, the ungulusaurs, a group of monodactyl hadrosauroids with hooves, hadrosaurs themselves, large megafaunal ornithopods, and a lot more medium-sized or small ornithopods throughout the country, however the ankylosaurs still remain, some having much more defensive builds with fused osteoderms on their tails and necks. Pachycephalosaurs are also extremely prevalent.

Due to the Great Biotic Interchange, there are also abelisaurs and the almost-extinct sauropods live in Central America and some parts of North America, but never gaining a secure foothold. There are also the dromaeosaurs of both continents, and their descendants, the avian dinosaurs. The avian dinosaurs, or birds are highly diverse, ranging from flightless aberrant enantiornithines, to swift jay-like neoavians. Ornithomimids and oviraptorosaurs are also very common.

### South America

The southern continent has seen a variety of environments. From the steaming hot jungles of the Amazon, to the wide open plains. Here, there are large oviraptorosaurs and ornithomimids, large ankylosaurs, slender piscivorous dromaeosaurs and abelisaurs. It is one of the places where tyrannosaurs have an almost secure foothold — they haven't completely had useless arms, and are more versatile at holding down prey.

It is one of the places where leptoceratopsids are more common than ceratopsids, as they presumably rafted to South America *before* the ceratopsids, and thus possibly have gained a more secure foothold. Here, there are also a lot of predator birds in the southern reaches of South America, like the hookjaw. There are also the Galapagos, the stretch of islands west of northern South America, which is well known for its unusual and unique fauna.

## Asia

*Australasia has its own section below.*

Asia might be one of the most biodiverse areas in the world of *New Dinosaurs*. Featuring a baffling diversity of ceratopsians, abelisaurs, ornithopods and a whole lot of other animals that are (mostly) unique to this landmass. The environment here is diverse; parts like what would be Mongolia are dry deserts, Yunnan is characterised by its thick cloud forests, and Russia is known for the taiga and tundras. When India, the subcontinent, crashed into Asia, large abelisaurs were introduced, alongside contemporary Indian fauna. It also fused with North America at one point, introducing the ungulusaurs to this continent. Africa also introduced fast, swift abelisaurs, some types of relict sauropods and other types, like coelurosaurian dinosaurs and some flightless birds. Pachycephalosaurs originating from Mongolia also appeared, becoming extremely specialised like the kappacephalids.

Australasia is also unique, having its own tropical, steamy jungles and quagmires, and its own biogeography is discussed below.

## Africa

Before crashing into Asia, Africa was an isolated continent, without much. Relict species thrived in this isolated, savannah environment. Thick, bulky sauropods, macropredatory abelisaurs and even large crocodile relatives ruled this land. For millions of years, it remained untouched. But after connecting with Asia, a lot of things changed. New species such as ceratopsians, ankylosaurs and a myriad of other dinosaurs had migrated over to Africa. Many large abelisaurs and sauropods went extinct due to this sudden change. Currently, the environment is mostly deserts, savannahs and some jungles.

## Australasia

Australasia consists of South East Asia, Papa New Guinea, Australia and corresponding islands. In this weird and wonderful place, there are a lot of unusual things. For one, there are **marsupial whales** and a high biodiversity of marsupials, avian dinosaurs and monotremes. Dinosaurs are more common around the Asian part of Australasia, but in Australia, mammals and birds are some of the most common. Dinosaurs here range from large, moa-like birds, ornithurines and many neoavian species. Another group of common dinosaurs are coelurosaurs and ornithopods, like ankylosaurs, dryosaur relatives and hadrosaurs.

Insular dwarfism and insular gigantism play a *major* role in this environment. There are dwarf ankylosaurs, hadrosaurs and giant ungulopterids, a group of flightless, hooved pterosaurs, massive marsupials and large paravians.

## Europe

Europe is well known for its unusual fauna. Ungulopterids originated here, aberrant, flightless pterosaurs with hooves as well as many clades of minorids, a widespread group of unusual, small hadrosauroids that live around Eurasia. There are also a large diversity of dinosaurs here, living in the crisp air of Europe. Many dinosaurs here are in fact, feathered. The cold, chilly winters here are long and desolate, and thus have evolved many features (ability to muscle quiver often to create heat, feathers, etc.) adapted for this harsh environment. It is one of the few places with few tyrannosaurs — most tyrannosauroids here are smaller, maybe because of the harsher environment. Many islands have the same insular dwarfism/gigantism traits that define other islands.

## Islands

I cannot fully do *all* islands, but you should know that islands are well known for unusual environments, and is a prime example of evolution. Take the Galapagos, an archipelago that surprisingly are dominated by *oviraptorosaurs,* of all dinosaurs. Madagascar, for example is an island with dwarf abelisaurs, omnivorous ornithopods and giant dromaeosaurs. From the Galapagos to Fiji, islands truly are some of the pinnacles of evolution.

## The Poles

The ice worlds of the extreme latitudes of the north and south host a unique array of dinosaurs and pterosaurs. This is a comprehensive summary of the species and the environment of all the glorious worlds of the Arctic and the Antarctic.

### Arctic

An ice world of snow, ice and sea, giant troodonts patrol the land, dwarf tyrannosaurids hunt for ungulosaurids and hadrosaurs in this environment. A huge diversity of maniraptoriformes are present, such as therizinosaurs, struthiomimids, troodonts, dromaeosaurs and paravians live in this cold world. Avialans are present in a huge diversity in this polar too, neornithines and their relatives present.

### Antarctic

Antarctica is a different story. There are no terrestrial non-avian dinosaurs, instead there are birds, pterosaurs and many species of mosasaurs and plesiosaurs in the deep, frigid depths.