The Nemegt formation biota

Because the Yixian was so well received, I decided to make another one! (More coming up btw!)
The Nemegt was 2nd in the poll so it gets before those.

The Nemegt is a well known late cretaceous formation from Mongolia, dating back to approximately 70 million years ago.
It's a dry landscape nowadays, which is why the formation is often shown as an arid ecosystem, but the formation's fossils show it would have been a lush floodplain with numerous rivers, lakes and mudflats able to support a rich fauna consisting of many multitonne animals.
Overall it maybe was comparable to Hell Creek in how it looked, but a bit wetter with more water and being a bit more tropical.

The formation's fossils don't include as much small animals as the Yixian, due to less favourable preservational conditions, but smaller animals from the formation include the mammal Buginbataar (not on the chart), the poorly known hesperornith Judinornis (which couldn't make it to the chart due to scaling issues: I can not find measurements) and the duck-like presbyornith/anseriform Teviornis and the more traditional Gurilynia.

The larger fauna mainly consisted of coelurosaurs: the herbivorous, high-browsing Therizinosaurus cheloniformis, the omnivorous oddball Deinocheirus mirificus and the area's top predator: Tarbosaurus bataar.
The formation includes 2 more ornithomimosaurs besided Deinocheirus: the more popular Gallimimus and the relatively obscure Anserimimus planinychus, both of which were likely prey to Alioramus altai (individual shown here is a sub-adult, the only adult material is in private hands).

On to the specifics of the fauna then!
*behaviour and colours are all speculative in this formation*

1. Teviornis gobiensis: this anseriform waterfowl is ecologically similar to ducks, and filters small animals from the water.
It is prey to many animals, if they can catch it, because it can fly well.
Scaling Teviornis is hard people, the size here is veeery rough, not precise.

2. Prenocephale prenes: A fairly small herbivore compared to the larger dinosaurs from the formation, this pachycephalosaur is still about boar sized, and equiped with a keratin-covered domehead.
They may have lived in small groups for protection, or maybe they were lone animals that preferred the dense bushing near the lakes, where it could easily break through with it's casque, like a cassowarry.

3. Gurilynia nesovi: just as imprecise as Teviornis 
This relatively mudane enantiornithine is respectably sized, but not outlandish.
It feeds of seeds and other plant matter and maybe occasionally small animals.

4. Mononykus olecranus: are small quirky little fuzzballs that are likely specialized insectivores, but may at times eat other small invertebrates.
With their long hindlimbs, they run very fast and often rush away with the slightest sound.
They use their small arms with hooked claws for breaking open insect burrows.

5.Adasaurus mongoliensis: A poorly known dromaeosaurid that may be a dromaeosaurine, or a velociraptorine.
It is ~1,8m long and weighs between 10 and 15kg like it's close(and much more popular) cousin Velociraptor.
They hunt smaller animals such as Teviornis, Mononykus, juveniles of many dinosaurs, small mammals and eggs.

6. Nomingia gobiensis: a 1,7m long, 20+ kg generalistic omnivore.
They are quick, cassowarry like animals that forage in the forest for most things that fit in it's beak.
That includes plant matter such as fruits and seeds and leaves, but also eggs and small animals such as lizards and mammals.
A study of oviraptorosaur foot morphology suggest they could kick quite hard, like a secretary bird.

7.Borogovia gracillicrus: Nemegt has a lot of troodontids, but Borogovia stands out because of it's unusual feet.
Instead of having 2 weight bearing toes and one sickle claw, Borogovia has 3 weight bearing toes, like the Naze dromaeosaur.
The tibiotarsus is also really elongated, suggesting this animal was very cursorial and agile.
It was roughly 2m long and 20 kg heavy.

8.Anserimimus planinychus: an obscure ornithomimid.
It is about 3m long and a little bit over 50 kg heavy, likely omnivorous.
It was fairly normal for ornithomimid standards, barring it's longer, more powerful front limbs.
This may have implications on it's ecology, it probably used it's hands a lot more, maybe they sustained longer wings than illustrated here.

9.Saichania chulsanensis: the smaller of the 2 ankylosaurs of the formation, being slighly smaller than Tarchia.
Being between 6,6 m and 5,2m, this extremely armored animal is no pushover, even compared to the largest Tarbosaurus.
I've speculated that their ecology was similar to hippos here fav.me/daj2u0m
A well aimed hit from that tail club can easily dislocate or break a Tarbosaurus jaw, hence, they are not commonly preyed upon.

10.Alioramus altai: falls between Tarbosaurus and Adasaurus in ecology.
It is faster and more gracile than both of those two predators, making them more inclined to hunting very fast, lighly prey, such as Anserimimus and subadult Gallimimus.
The individual shown here is a subadult, the only adult material is in private hands.

11. Tarbosaurus bataar: the resident badass apex predator of the formation.
It hunts most of the animals in the formation, granted they aren't too small or too big (it aint going after full grown Deinocheirus....)
They are built more gracefully than it's very close cousin Tyrannosaurus, meaning it probably went after more agile prey regularly (see skeletal used here: fav.me/d95di0r )
Their eyes face less forward than in Tyrannosaurus, meaning it's vision wasn't as great.

12. Deinocheirus mirificus: this amazingly weird ornithomimosaurus is basically a giant hump-backed duck with 2,4m long arms topped with heavy curved claws.
It's stomach contents show that it at least occasionally ate fish, but it would probably mostly be a herbivore.
They are bulky animals that are, when adult, quite a few pounds heavier than Tarbosaurus, making it unlikely prey.
I've decided to take away a little bit of feathers, because in my last drawing I overdid them.

13.Saurolophus angustirostris: the resident large hadrosaur, analogous to Hell Creek's Anatosaurus/Edmontosaurus.
It can reach lengths greater than 12m, but is usually smaller.
They move in herds for protection, and take care of their young.

14.Gallimimus bullatus: many people see this bird-like animal as defenseless, but the opposite is true.
It is quite huge, and weighs over 500 kg heavy, a kick can easily shatter a ribcage of many similarly sized predators, and it's quite quick.
They are often preyed upon by sub-adult-but-quite-big Tarbosaurus, but only in ambush.
They forage in small flocks for mostly delicate plant matter, but also small animals.

15. Therizinosaurus cheloniformis: a goofy giant-clawed chicken.
Individual with colour is holotype, while the uncoloured silhouette is a larger specimen.
They are high browsers (~5m) and use their claws for bringing down branches, as well as defense against predators and visual display purposes.

I do not own references used, they belong to GetAwayTrike, Qilong, Scott Hartman and Szymoonio.


I hope you enjoyed  (imo the Yixian chart is better though)
Solnhofen is next.