The 40-odd species of the Cedunasauria form (along with the alvarezsaurs) the rather impoverished Australasian theropod fauna. The living cedunasaurs are an extremely varied group of animals and external generalizations are difficult. All extant forms have lost their hallux and often possess a long, extendible tongue. DNA hybridization confirms the monophyly of this group.
The exact origins of Cedunasauria are unclear; these dinosaurs are clearly coelurosaurs, but lack true feathers and maniraptor-style forelimbs. The Gondwanan fossil record for small Cretaceous theropods is very sparse, however a possible relative might be the African coelurosaur Nqwebasaurus (although studies show that Nqwebasaurus is a kind of ornithomimosaur, meaning the Cendasaurs are either unrelated, or are the only ornithomimosaurs that are alive today).
Fragments of possible cedunasaurs are known from the Early Eocene Tingamarra fauna. The group becomes common in the Oligocene as small, gracile predators, of which similar forms survive to this day. Cedunasaurs soon branched out into several specialized families including toothless ornithomimosaur and therizinosaur analogues.
However, recent examinations have revealed something rather interesting. The earliest known cedunasaur comes from the Eocene of Messel Pit in Europe, having certainly shared its habitat with early errosaurs and a wide variety of other theropods such as abelisaurs and ornithomimids. Body shape wise, its fairly similar to modern basal cedunasaurs, having a body design typical of "generic" coelurosaurs; based on the very well preserved specimens, it was covered in a coat of down, except for the legs and the belly and tail underside, which were scaly. The asian origins of cedunasaurs, which seem extremely out of place in a world dominated by more "advanced" coelurosaurs like tryannosaurs and maniraptoriformes, suggest these animals are of Indian origins, later having spread on Eurasia. the later arrival of mattiraptors and manticorants from Africa reduced most cedunasaurs to dust, except the mere handfull of species that made it into Australia.
Two species are known, Protocedunosaurus foxi and Protocedunosaurus messelensis. The first is chicken sized, the later was as big as an heron and there are several anatomical reasons to think it lived like one too.
Perhaps owing to the extinction of Australia's abelisaurs and deinonychosaurs, cedunasauria briefly dominated the continent's large predatory guilds during the Oligocene, producing bulky, carnosaur-like forms (the torvodontids). But at the start of the Neogene, the group began to face stiff competition from the early rhynchoraptors as these killer ornithopods became increasingly large and carnivorous, the same case can be applied to flightless pterosaurs.
Throughout the Miocene, the torvodonts were edged out by the rhynchoraptors and flightless pterosaurs until only a few huge species remained. During the Tortonian, they produced their final and most impressive offering, the 15-meter-long Pikodon maximus. With the extinction of this tyrannosaur-like monster at the end of the Miocene, control of the large predatory niches fell entirely to the rhynchoraptors and carnocursors.
However, many of the smaller cedunasaurs survived, including the edentulous non-predators. These flourished throughout the Neogene evolving many strange forms, most of which survive to this day. Despite this, their only major competition being a group of small predatory mammals native in the area.
CEDUNASAURIDAE (Warriguls and cedunsaurs)
Cedunasaurids are the basal-most members of Cedunasauria, and are the most common family in the group. These conservative little predators adhere to the basic coelurosaur body-plan, possessing a long neck and tail, powerful hindlimbs, small forelimbs, and a mouth full of needle-like teeth. In sum, cedunasaurids very much resemble primitive coelurosaurs like Compsognathus, which thrived in the Jurassic, over 150 million years ago. Most cedunasaurids are small, though some exceed two meters in length, and all are carnivores subsisting on small game. Many species of rhynchoraptors compete for similar niches, but partitioning has allowed the cedunasaurids to survive alongside these ornithopod upstarts. While rhynchoraptors are pursuit predators (with a hunting strategy similar to RL dogs), cedunasaurs are generally ambush predators (like cats). A few pursuit-predator cedunasaurs do survive, but these are restricted to the island of Tasmania, where the rhynchoraptors have so far failed to gain footing, their only compeition being a few species of flightless pterosaurs.
Warrigul (Cedunasaurus vulgaris)
Bushbarker (Cedunasaurus latrator)Bushbarkers are among the largest predatory cedunasaurs, second only to warriguls. They seem to have evolved convergently with deinonychosaurs and troodontids but aren't quite as effective predators as their laurasian counterparts. Bushbarkers have enlargened claws on their inner pedal digits, but the toes are not hyperextendable. This along with some other evidence suggests that they started off on this evolutionary path relatively recently.These predators were named after their loud doglike barking sounds before a single specimen was caught. Bushbarkers are crepuscular hunters, usually going after small mammals, birds, reptiles and anything else they can catch. Several subspecies are found in different parts of Australia and one in Tasmania, with a size range between 1 and 5 kg. Two subspecies have been known to exist, Clive's bushbarker, Cedunasaurus latrator barkeri and thick-tailed bushbarker, Cedunasaurus latrator crassicaudatus.
Puffindingo (Dingolophosaurus abramsi)
Glasseye Cedunasaur (Microcedunasaurus kiddi)
This tiny, rare theropod is restricted to the dense forests of the southwest. It is a nocturnal insectivore of the forest floor, disappearing into the brush at the slightest danger. Its secretive nature results in very little being known about it.
Fancypants (Microcedunasaurus regalis)Probably the rarest of the cedunasaurs, the fancypants is known from only a single preserved specimen and a handful of eyewitness reports. Fancypantses dwell deep within the forests of eastern Australia, and probably favor a predatory lifestyle like their close relatives, the glasseye cedunasaurs Often over a meter in length, fancypantses are slightly larger than their western cousins, but are similarly skittish, and so few of these creatures have ever been seen.
The holotype specimen, taken near Spec's Brisbane, is the only tangible evidence of the this species exsistance. This male (presumed adult) sports a coat of vividly-colored plumage, with a naked head dyed brilliant red, yellow and green. Scientists speculate that this coloration is a sexual display, but beyond this assumption, the behavior of the fancypants is unknown.
The Austrsliatheres are a small group (two genera and species are currently known) of very large cednusaurs. Although they superficially resemble torvodonts they are a far more recent group, originating in the Pliocene. Both species are most common in the most arid regions of Australia, where Carnocursorids and Rhynchoraptors are scarce.
Lightning Ridge Snagger (Australiatherium fulguriugo)
Australiatherium fulguriugo (Australia's beast from lightning ridge), commonly known as The Giant or Lightning ridge Snagger. They are the largest confirmed australiathere, measuring up to 18 feet, still not huge for a theropod. It is found mostly in Centralmost Australia but was first discovered in Lightning ridge, hence the name. Unlike it's smaller cousin, it is a complete carnivore and uses its huge claws to dispatch it's prey, which mainly includes Euclasaurs. It is a sandy brown, with distinctive black markings on its back.
Humpback Monster (Irrisaurus ukranensis)
This smaller cousin of the Lightning Ridge Snapper lives exclusively in the Australian Outback. While most of its body is covered in dull grey protofeathers and scales, it has a huge sail on its back with a rainbow of colors, hence the name. The colorful quills on it's back are poisonous. The reason for the eccentric coloration are unknown, probably for mating or other display. Not much more is known about this reclusive species.
The high-browsing chimerasaurs get their name from their seemingly composite bodies that combine the long legs of an extinct ornithomimosaur, the sharp foreclaws of a therizinosaur, a featherless body and a sauropod-like head. Despite their carnivorous ancestry, these creatures are actually gentle herbivores.
Giant Chimeasaur (Chimerasaurus maximus)The giant chimerasaur (Chimerasaurus maximus) is the largest living cedunasaurian at 10 meters (mostly neck and tail) but, at less than 2 tons, is extremely light for its size. Chimerasaurs are built for high browsing with long legs and neck plus an extendible tongue for reaching otherwise inaccessible foliage. Their primary defense against the predatory pterosaurs and rhynchoraptors is their speed, but when cornered they attack viciously with powerful kicks and swipes of their long claws.
Chimerasaurs are animals of sclerophyll forests, and have developed a unique way of coping with the p-Eucalyptus leaves that form the bulk of their diet. These plants produce oil-rich foliage containing phenolic compounds and cyanide precursors. To cope with this, the gizzard of a chimerasaur contains a unique flora of symbiotic fungi which secrete an orlistatic chemical that suppresses the gut's ability to absorb oils. Much of the oil thus passes straight through the digestive tract and results in extremely pungent-smelling droppings. The animal also has a very large liver that detoxifies what oil is absorbed and phenolic compounds.
Spiny Chimerasaur (Chimerasaurus biggasi)The spiny chimerasaur (Chimerasaurus biggasi) is a poorly known chimerasaur species five to six meters long. It is more robustly built than its larger cousin, the giant chimerasaur. The defining characters of this species are stiff quill-like spines on its neck, back and tail and rows of bony scutes protecting its belly.
- Brian Choo, Daniel Bensen, Clayton Bell, and Matti Aumala
,=C. vulgaris (Warrigul) ,=Cedunasaurus=| | `=C. latrator (Bushbarker) ,=| | `=Dingolophosaurus abramsi (Puffindingo) ,=Cedunasauridae=| | | ,=M. kiddi (Glasseye cedunasaur) =Cedunasauria=| `=Microcedunasaurus=| | `=M. regalis (Fancypants) | | ,=C. biggasi (Spiny chimerasaur) `=Chimerasauridae=Chimerasaurus| `=C. maximus (Giant Chimerasaur)