The Yixian formation biota

Not all of course! But a lot! 

Ok, so I've decided to do it more like a field guide style, with more info on the animals and the formation itself, and I have put extra work in it to make it more badass.
Cuz Yixian deserves that.
And you voted for it. :I 


*takes a deep breath*



The Yixian formation is an early cretaceous geological formation from Jinzhou, Liaoning in China.
It is well renowned for it's huge ammount of fossils, including many exquisitely preserved ones, to such an extent that we could figure out the colours of some of the animals.
In the early cretaceous, the Yixian would have had a moderate year round temperature, and was able to support a rich aboreal fauna, with many species of enantiorniths (primitive birds) , pterosaurs, and climbing deinonychosaurs such as Sinornithosaurus millennii.
The formation was wel-watered with lots of streams crossing the ancient landscape, and volcanoes (both of which accounted for the extremely nice preservational conditions).
While the formation is mainly known from it's tiny feathered denizens, it also supported some ferocious beasts and big herbivores, namely the famous fuzzed 9m tyrannosauroid Yutyrannus huali and the bulky 14m long ophistocoelicaudine Dongbeititan dongi.
The formation's flora was comprised mostly of many species of conifers, ferns, ginkgo's, horsetails and even a lot of flowering plants, among which was the oldest carnivorous plant known thus far.
There are also many known arthropods from the formation, ranging from a few species of flies and wasps, to spiders and dragonflies, eaten by the local birds, pterosaurs and maybe some non avian dinosaurs.

Let's get started to the specific animals that I have illustrated here:
*behaviours and colours are speculative unless otherwise noted*

1. Callobatrachus sanyanensis : this ~10cm long anuran is considered the most basal member of the discoglossidae family, and was likely prey to many aquatic and semi-aquatic animals, as well as birds such as Changchengornis and some piscivorous pterosaurs.

2. Repenomanus robustus: Often being hailed as ''the mammal that ate dinosaurs!!1!!!'' this carnivorous mammal was indeed very big by mammalian standards of it's age.
It was however, just under 3 ft long and was preyed upon by many Yixian dinosaurs, and was pressed away into the niche of small generalistic forager.
It's larger cousing would have been 12-16 kg.

3. Sinocalliopteryx gigas: this fluffy predator is the largest compsognathid discovered thus far, and would have been a deadly predator.
The holotype was 2,4 m long, but a larger specimen has been discovered since then.
It would have been an agile predator of smaller animals, which are abundantly represented in the fossil record of the Yixian.

4.Beipiaosaurus inexpectus: this basal therizinosaur is prey to Yutyrannus and if unlucky also to Sinocalliopteryx, but it did have good ways of defending itself: it had strong arms topped with 3 large, curved claws, and it could climb trees.
The fossils preserve feathers, and before Yutyrannus, it was the largest non-avian dinosaur with feathers discovered.
Through research it was found out that it's neck fuzz was partially brown.

5.Hyphalosaurus lingyuanensis : This aquatic reptile represented a major part of the yixian formation aquatic biota, with literally thousands of fossils representing it. It would have been an agile swimmer preying on small fish and swimming invertebrates.
It would have been prey to the larger pterosaurs from the yixian, as well as small theropods that would have ''fished' occasionally.

6. Protopsephurus liui : A 80cm long paddlefish related to, and really similar to, modern paddlefish.
Their noses are highly sensitive and are used to sense movement in the water.
These fish feed by filtering water through their gills and open mouth, like a miniature basking shark.
A fairly common prey item for fishing theropods.

7. Sinornithosaurus millenni: An aboreal, gliding dromaeosaurid with large wings.
It is the bane of all things small, like it's cousin Microraptor and Changyuraptor also were.
The range of prey items is quite impressive: they hunt fish, birds, other non-avian dinosaurs such as Jeholosaurus and juveniles of many species, as well as the eggs. 
I have illustrated it slighly too big here btw.

8. Caudipteryx zoui : A chicken-like theropod that scurries around in the underbrush, moving in small flocks of 3-7 individuals.
They usually eat seeds, tubers and larvae, as well as fallen fruits and small vertebrates such as lizards (Liushusaurus, Xianglong etc).
A favourite prey item of Sinocallopteryx, as well as Dilong.
they take care of their chicks.
[It was black instead of the colour shown here, I found out after I made this drawing]

9.Dilong paradoxus: The tiny tyrant.
This 1,6m tyrannosauroid (this is not fully grown, adults may have been 2m or slighly more) is a very swift hunter in loosely organized mobs.
They often move in groups with a hierarchy similar to groups of crocodiles, and can easily overwhelm Beipiaosaurus.
Though they prefer less fierce prey most of the time.

10. Jeholosaurus shangyuanensis: is the Yixian equivalent of a rabbit: it is small, fast, nervous and burrows.
The holotype was around 70cm long and 30cm tall, but it was not fully grown. Adult size is not known.
They breed very quickly, and get killed off very quickly because many predators eat them.
Jeholosaurus' diet mainly consists of seeds, leaves, fruits and small insects.

11. Zhenyuanlong suni : this large-winged dromaeosaurid is the first terrestrial ''raptor'' with well preserved feather covering, so it is quite significant for our understanding of dromaeosaurid integument.
It is a roughly 1,7m long predator that mainly hunts smaller animals, but also occasionally hunts animals as large or slighly larger than itself.
They are solitary predators and mate for life, like raptors.

12. Bolong yixianensis: is a common low browser that moves in loose herds of a few individuals, mixed ages.
They are often quite calm because not many animals hunt them, but a large Yutyrannus huali can easily pick one off, but subadult Yutyrannus have to watch out for the fury of angered herds.
They have strong hands and beaks for more tough plant material than most herbivores in the formation.

13. Yutyrannus huali : The unchallenged apex predator of the formation (except for that undescribed possible carnosaur :I).
It is a primitive, 9m long tyrannosauroid, and was completely covered in simple feathers, with the longest ones of the neck and arms.
In hunting style it is more similar to carnosaurs than to Tyrannosaurus itself: with cutting teeth and long claws.
They sometimes hunt in small units, but these can split apart when food is scarce, and form again when food is abundant: a large group is the only animal capable of killing (almost)adult (but sick) Dongbeititan dongi.

14. Psittacosaurus lujiatunensis: a basal 1,7m long ceratopsian with quills on it's tail.
It is the only mesozoic scaly animal with a known colour scheme, as depicted here.
It eats anything that fits in it's mouth and is digestible, meaning it eats lots of fibrous plant material, as well as small invertebrates and lizards, not unlike a modern boar.
It's temperament is also boar-like, it can deliver a nasty bite or a spiky tail slap.

15. Dongbeititan dongi: the true titan of the formation (though still small by sauropod standards) towers over all animals except Euhelopus sp..
It's bulky body and armor make it nearly immume to predation when adult, but juveniles are very vulnerable.
It feeds of the higher vegetation, and often pushes over trees to make them easier to reach.
No predator wants to mess with these.

16. Moganopterys zhuiana: the largest Yixian pterosaur is a delicate animal that feeds on aquatic animals such as fish, slugs and small Hyphalosaurus.
It has a wingspan of over 5m, possibly 7m, making it quite imposing, but it is really light.
They are almost exclusively found around the abundant Yixian lakes, and stroll through the shallow water like a heron or a stork, probing the ground with it's needle-like jaw.

17. Gladocephaloides jingangshanensis: Are small pterosaurs that fly around the well-watered marshes on the hunt for tiny shellfish and crustaceans and fish.
They are great flyers but also spend a lot of time swimming, diving after their preferred prey items.
Their wingspan is a little over 60cm.

18. Beipiaopterus chenianus: is a ctenochasmid pterosaur, overall very similar to Glabocephaloides but instead filters microscopic life from the water, and is overall a little larger.

19. Bohaiornis guoi: the largest enantiornithine, and likely raptorial in nature, this beefy bird is a winged menace to many smaller animals, including pterosaurs.
It has a broad snout lined with sharp teeth and it has strong claws used to dispatch prey.
They don't have the wings suited for long flight and soaring: instead, it flies from brach to branch and takes a vantage point to attack other animals, not unlike a goshawk.
Crap: made a scaling error, making the individual shown here too big!

20. Shanweiniao cooperorum: a relatively small bird that feeds on seeds and other plant matter, it lives in small, lively flocks and cheerfully tweets through the forest. :3
They are agile flyers, but still sometimes prey to Bohaiornis.

21. Confuciornis sanctus: this generalistic, beautiful bird is the oldest bird with a beak, making it look pretty modern.
Until you see it's large manual claws, probably used to cling on treebark and rockfaces, as well as titanosauriforms.
They have large ribbon-like feathers on it's tail, with beautiful feathers.
Their flight skills aren't the best though.

22. Lichnoplecia kovalevi: at the base of the foodchain we find this diminutive fly. Poor thing. Located next to that black spot. 
XD


PHEW. That is a long description, so here is a TD;LR: Yixian is awesome!

I hope you guys enjoyed it 

References used do not belong to me, they belong to:
BricksmashTV
GetAwayTrike
Pteros
Frans-Jozef
Randomdinos
rest is extrapolated from fossils.