Lagerpeton

By Tas 

Etymology: Rabbit Reptile 

First Described By: Romer, 1971 

Classification: Biota, Archaea, Proteoarchaeota, Asgardarchaeota, Eukaryota, Neokaryota, Scotokaryota Opimoda, Podiata, Amorphea, Obazoa, Opisthokonta, Holozoa, Filozoa, Choanozoa, Animalia, Eumetazoa, Parahoxozoa, Bilateria, Nephrozoa, Deuterostomia, Chordata, Olfactores, Vertebrata, Craniata, Gnathostomata, Eugnathostomata, Osteichthyes, Sarcopterygii, Rhipidistia, Tetrapodomorpha, Eotetrapodiformes, Elpistostegalia, Stegocephalia, Tetrapoda, Reptiliomorpha, Amniota, Sauropsida, Eureptilia, Romeriida, Diapsida, Neodiapsida, Sauria, Archosauromorpha, Crocopoda, Archosauriformes, Eucrocopoda, Crurotarsi, Archosauria, Avemetarsalia, Ornithodira, Dinosauromorpha, Lagerpetidae 

Referred Species: L. chanarensis 

Status: Extinct 

Time and Place: About 235 to 234 million years ago, in the Carnian of the Late Triassic 

Lagerpeton is known from the Chañares Formation in La Rioja, Argentina 

Physical Description: Lagerpeton was named as the Rabbit Reptile, and for good reason – in a lot of ways, it represents a decent attempt by reptiles in trying to do the whole hoppy-hop thing. You might think that it resembles Scleromochlus in that way, and you’d be right! Scleromochlus and Lagerpeton are close cousins, but one is on the line towards Pterosaurs – Scleromochlus – and the other is on the line towards dinosaurs – Lagerpeton. So, hopping around was an early feature that all Ornithodirans (Dinosaurs, Pterosaurs, and those closest to them) shared. Lagerpeton itself was about 70 centimeters in length, with most of that length represented as tail; it was slender and lithe, built for moving quickly through its environment. It had a small head, a long neck, and a thin body. While it had long legs, it also had somewhat long arms, and while it may have been able to walk on all fours it also would have been able to walk on two legs alone. It was digitigrade, walking only on its toes, making it an even faster animal. Its back was angled to help it in hopping and running through its environment, and its small pelvis gave it more force during hip extension while jumping. In addition to all of this, it basically only really rested its weight on two toes – giving it even more hopping ability! As a small early bird-line reptile, it would have been covered in primitive feathers all over its body (protofeathers), though what form they took we do not know. 

By Scott Reid 

Diet: As an early dinosaur relative, it’s more likely than not that Lagerpeton was an omnivore, though this is uncertain as its head and teeth are not known at this time. 

Behavior: Lagerpeton would have been a very skittish animal, being so small in an environment of so many kinds of animals – and as such, that hopping and fast movement ability would have aided it in escaping and moving around its environment, avoiding predators and reaching new sources of food (and, potentially, chasing after smaller food itself). Lagerpeton may have also been somewhat social, moving in small groups, potentially families, to escape the predators and chase after prey together, given its common nature in its environment. As an archosaur, Lagerpeton was more likely than not to take care of its young, though we don’t know how or to what extent. The feathers it had would have been primarily thermoregulatory, and as such, they would have helped it maintain a constant body temperature – making it a very active, lithe animal. 

By José Carlos Cortés 

Ecosystem: Lagerpeton lived in the Chañares environment, a diverse and fascinating environment coming right after the transition from the Middle to Late Triassic epochs. Given that the first true dinosaurs are probably from the start of the Late Triassic, this makes it a hotbed for understanding the environments that the earliest dinosaurs evolved in. Since Lagerpeton is a close dinosaur relative, this helps contextualize its place within its evolutionary history. This environment was a floodplain, filled with lakes that would regularly flood depending on the season. There were many seed ferns, ferns, conifers, and horsetails. Many different animals lived here with Lagerpeton, including other Dinosauromorphs like the Silesaurid Lewisuchus/Pseudolagosuchus and the Dinosauriform Marasuchus/Lagosuchus. There were crocodilian relatives as well, such as the early suchian Gracilisuchus and the Rauisuchid Luperosuchus. There were also quite a few Proterochampsids, such as Tarjadia, Tropidosuchus, Gualosuchus, and Chanaresuchus. Synapsids also put in a good show, with the Dicynodonts Jachaleria and Dinodontosaurus, as well as Cynodonts like Probainognathus and Chiniquodon, and the herbivorous Massetognathus. Luperosuchus would have definitely been a predator Lagerpeton would have wanted to get away from – fast! 

By Ripley Cook 

Other: Lagerpeton is one of our earliest derived Dinosauromorphs, showing some of the earliest distinctions the dinosaur-line had compared to other archosaurs. Lagerpeton was already digitigrade – an important feature of Dinosaurs – as shown by its tracks, called Prorotodactylus. These tracks also showcase that dinosaur relatives were around as early as the Early Triassic – and that their evolution, and the rapid diversification of archosauromorphs in general, was a direct result of the end-Permian extinction. 

~ By Meig Dickson

Sources Under the Cut  

Chiappeavis magnapremaxillo

By José Carlos Cortés

Etymology: Chiappe’s Bird

First Described By: O’Connor et al, 2016 

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Averaptora, Avialae, Euavialae, Avebrevicauda, Pygostaylia, Ornithothoraces, Enantiornithes, Cathayornithiformes 

Status: Extinct

Time and Place: 120 million years ago, in the Aptian age of the Early Cretaceous 

Chiappeavis is known from the Jiufotang Formation of China, specifically in the Shangheshou Beds 

Physical Description: Chiappeavis was an Opposite Bird, ie the group of bird-like dinosaurs that were extremely diverse and widespread during the Cretaceous period. Chiappeavis is known from a nearly complete skeleton, including some feather impressions. It was a fairly large bird, probably around 20 or so centimeters (though this is a very rough estimate). It had a small snout, with small pointed teeth inside of it, and a fairly large head. Its body was long, and it had large wings – good for more powerful flying as opposed to tighter maneuvering in between trees. Interestingly enough, Chiappeavis had a giant tail fan, which was not actually universal among Opposite BIrds as it is in modern birds. It also had fairly thick, strong feet. 

Diet: It is probable that Chiappeavis fed mainly on arthropods and other hard invertebrates. 

By Ripley Cook

Behavior: It is uncertain what the behavior of Chiappeavis was, given that we do not have extensive skeletons of this dinosaur. Still, it probably wouldn’t have flitted about the trees as much as birds with wings better built for maneuvering. The tail fan of Chiappeavis probably would have been extremely useful in sexual display, as well as other forms of communication – especially since it does not appear to have been very good at generating lift during flight (hence it not being widespread in other Opposite Birds). As such, it is more likely than not that Chiappeavis would have been fairly social, living in groups of multiple birds which communicated and recognized each other with feather displays. This, therefore, leads us to yet another likely hypothesis: that it took care of its young, at least to some extent. Beyond that, the behavior of Chiappeavis is a bit of a question – though it may have been able to dig out insects and other grubs with its strong feet, and then bit into the tough exteriors of these animals with its many needle-like teeth. 

Ecosystem: The Jiufotang Formation was one of the Jehol Biota ecosystems, aka a group of extremely diverse and lush environments that preserved birdie dinosaurs of the Early Cretaceous with great detail. In that, Chiappeavis is one of many dinosaurs found in this location with extensive feather preservation. TheJiufotang Environment was a dense forest, surrounding an extensive number of lakes, and near volcanically active mountains. Still, it isn’t quite as well known as the earlier Yixian formation, and in fact doesn’t seem to have as many plants preserved to inform the exact environment and temperature. Still, it’s reasonable to suppose it may have also been a temperate ecosystem, like the earlier Yixian Formation, potentially even with snow. 

By Jack Wood

In this environment, there were an extremely wide variety of animals. There was a decent diversity of fish, quite a few kinds of mammals, and the weird, unclassifiable Choristoderes were represented by Philydrosaurus, Ikechosaurus, and Liaoxisaurus. This ecosystem was lousy with pterosaurs, featuring a variety of Chaoynagopterids – like Chaoyangopterus itself, Eoazhdarcho, Jidapterus, and Shenzhoupterus; Pteranodonts like Guidraco, Ikrandraco, Liaoningopterus, Nurhachius, Liaoxipterus, and Linlongopterus; Tapejarids like “Huaxiapterus”, (probably) Nemicolopterus, and Sinopterus; and the weirdly late-surviving Anurognathid Vesperopterylus. 

As for dinosaurs, there were many, and most were bird like! There was of course the Ankylosaur Chuanqilong, and the early Ceratopsian Psittacosaurus; there was also an unnamed titanosaur. There was a Tyrannosauroid, SInotyrannus, the Chickenparrot Similicaudipteryx, the raptor Microraptor, and tons of early Avialans like Confuciusornis, Dalianraptor, Jeholornis, Omnivoropteryx, Sapeornis, Shenshiornis, and Zhongjianornis. There were also “true” birds (ie, the line of dinosaurs that would evolve into those we see today) such as Bellulornis, Piscivoravis, Archaeorhynchus, Chaoyangia, Jianchangornis, Parahongshanornis, Schizooura, Songlingornis, Yanornis, and Yixianornis. However, the most diverse group of dinosaurs were the Opposite Birds, of which Chiappeavis was only one of many. There was Alethoalaornis, Boluochia, Bohaiornis, Cathayornis, Cuspirostrisornis, Dapingfangornis, Eocathayornis, Piscivorenantiornis, Pengornis, Gracilornis, Huoshanornis, Largirostrornis, Longchengornis, Longipteryx, Rapaxavis, Shangyang, Sinornis, and Xiangornis – just to name a few! As such the Jiufotange remains as a rich ecosystem in which to study the evolution of this fantastic group of Cretaceous dinosaurs. 

By Scott Reid

Other: Chiappeavis is probably not its own thing – it is one of a number of Opposite Birds described without substantial evidence that it was a distinct genus and, indeed, many researchers consider them to be members of other genera. In this case, Chiappeavis is probably the same as Pengornis. Still, until it is officially lumped in, it must be treated as its own genus. It had a lot of similarities to Pengornis, regardless, indicating the two may belong to a larger clade of Opposite Birds. In short, Opposite Bird Phylogeny is kind of a mess, and needs a lot more intensive work than has currently been done. 

~ By Meig Dickson

Sources Under the Cut 

Nanningosaurus dashiensis

By José Carlos Cortés

Etymology: Nanning City Reptile 

First Described By: Mo et al., 2007 

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Ornithischia, Genasauria, Neornithischia, Cerapoda, Ornithopoda, Iguanodontia, Dryomorpha, Ankylopollexia, Styracosterna, Hadrosauriformes, Hadrosauroidea, Hadrosauromorpha, Hadrosauridae, Euhadrosauria, Lambeosaurinae 

Status: Extinct

Time and Place: Sometime in the Maastrichtian age of the Late Cretaceous, between 72 and 66 million years ago 

Nanningosaurus is known from the Dashi Site in Guangxi, China 

Physical Description: Nanningosaurus is, sadly, only known from a very incomplete and partial skeleton, which does include parts of the skull and jaws. Thus, it is difficult to say what it would have looked like beyond being a Hadrosaur. It seems most likely that it was a Lambeosaurine, or Hollow-Crested Hadrosaur, though of course we don’t know if it actually had a crest or not. As such, all we can know is that it would have been a fairly bulky animal, covered in scales, with a duck-like beak and potential display or communication structures on its head. It also may have had hooves, like other hadrosaurs, on its front feet. Because of course they did. 

Diet: Being a hadrosaur, Nanningosaurus would have mainly fed upon soft, wet plants, such as those found around or in sources of water. It would have then used its thousands of teeth to mash it up into a paste, to make the leaves easier to swallow. 

Behavior: Obviously, we don’t know a lot about the behavior of Nanningosaurus because, again, we don’t have a lot of fossils of it. As hadrosaurs, they would have been very social animals, living in large herds. It would have taken care of its young, potentially in communal nesting grounds with large mounds to hold the eggs in and rotting vegetation to keep the eggs warm. It probably would have had somewhat complex social displays, potentially using color and sound, in order to communicate with other members of the herd and to find mates. It also may have used this communication to warn the herd of predators, though no predators were found with Nanningosaurus. 

Ecosystem: Nanningosaurus is not known from a very well studied fossil site – it doesn’t even have a formation name! It does seem to have been a muddy environment, indicating some sort of source of fresh water and probable frequent rains. Here, Nanningosaurus lived alongside the titanosaur Qingxiusaurus, which is also only known from limited remains. 

Other: While the exact nature of Nanningosaurus is rather murky, it is a very important fossil discovery – it’s one of the most Southern Asian Hadrosaurs! As such, as we learn more about it, we will be able to piece together the evolutionary puzzle of this wonderful dinosaur group a little clearer. 

~ By Meig Dickson

Sources Under the Cut 

Suskityrannus hazelae

By Ripley Cook

Etymology: Coyote Tyrant 

First Described By: Nesbitt et al., 2019

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Tyrannosauroidea, Pantyrannosauria 

Status: Extinct 

Time and Place: Sometime between 93.5 and 89.3 million years ago, in the Turonian of the Late Cretaceous 

Suskityrannus is known from the Lower Member of the Moreno Hill Formation 

Physical Description: Suskityrannus was probably around four meters long in life – as both of the fossils that have been found of it are from juveniles, the sizes of these fossils (1 and 3 meters long respectively) were probably not the maximum size this dinosaur achieved. In fact, at least one of the known fossils was three years old when it died – and tyrannosaurs tend to age at a similar rate to people. That being said, it is more likely than not that Suskityrannus was a slender animal, similar to other early tyrannosaurs rather than the later bulky behemoths of greater fame. It actually had a fairly large brain, compared to its body, which may be an indicator that it was a smart little dinosaur. Finally, as an early Tyrannosaur, and a small one at that, it would have been covered in fluff all over its body, potentially even with fancier feathers on its arms. 

Diet: As a Tyrannosaur, Suskityrannus would have fed primarily on small animals, most likely smaller dinosaurs. 

Behavior: Given that multiple younger individuals were found together, it is likely that Suskityrannus was at least somewhat social, potentially living in family groups or small “packs” (in that they were groups of individuals that hunted together, but they probably wouldn’t have had anything resembling a sophisticated hierarchy within said grouping). As warmblooded animals, they would have been active frequently, and used that ability in order to catch their equally-lively food. And, in addition, they probably would have taken care of their young – especially if they were social. Beyond that, we need more fossil evidence to determine – though, the results could be interesting in determining how the later, larger tyrannosaurs also behaved. 

By Scott Reid

Ecosystem: Moreno Hill was a wet floodplain, filled with an extensive river system that flooded each wet season and dried up rapidly when the rains ended. An extreme amount of coal is known from this environment, and as such it is logical to suppose that it was a fairly dense (most likely coniferous) forest with a consistent underlying layer of ferns and lilies in the wetter, riverside areas of the environment. Despite this clear evidence of diverse plantlife, we know little about the animals present in the Moreno Hill Environment. Fish are known, and named, from here – including Melvius – as well as unnamed turtles and crocodylomorphs. Only three other dinosaurs are named from this environment, though they are some of the more fascinating dinosaurs from the “mid” Cretaceous of North America. They include Jeyawati, a weird looking almost-hadrosaur with a sloping-facep; Nothronychus, a pot-bellied therizinosaur and one of the few known from North America; and Zuniceratops, a stepping stone between ceratopsians like Protoceratops and the iconic large ceratopsids of the Late Cretaceous (such as Triceratops). Suskityrannus probably mainly fed on Zuniceratops, given both were of a smaller size than the other dinosaurs of the neighborhood. 

Other: Suskityrannus is an important stepping stone – an intermediate between the skinny tyrannosaurs of the Early Cretaceous and the bulky terrors of the Late Cretaceous. This makes the discovery of this dinosaur one of the more important ones in terms of understanding tyrannosaur evolution. While, for now, only young of this dinosaur are known, further study of Suskityrannus will allow for more understanding of how these animals went through their rapid evolution in the middle of the Cretaceous period. 

~By Meig Dickson

Sources Under the Cut 

Deinocheirus mirificus

By Ripley Cook

Etymology: Horrible Hand 

First Described By: Osmólska & Roniewicz, 1970 

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Ornithomimosauria, Ornithomimoidea, Deinocheiridae 

Status: Extinct 

Time and Place: 70 million years ago, in the Maastrichtian of the Late Cretaceous 

Deinocheirus is known from the Nemegt Formation of Ömnögovi, Mongolia 

Physical Description: Deinocheirus is one of the absolute weirdest, fantastical, most surprising discoveries of the 2010s in paleontology, and the answer to a mystery older than most of the readers of this blog. Deinocheirus was originally known from two very long, distinctive arms – arms so long, that they could very easily engulf a person. In fact, many of the photographs of the fossil are of an individual standing in between the hands, in order to give scale to them. But these arms and hands gave very little in the way of information about what Deinocheirus looked like. Eventually, it was determined that Deinocheirus was an Ornithomimosaur – but the scale of the arms indicated it would be a ridiculously huge Ornithomimosaur. 

By Slate Weasel, in the Public Domain

And then, luckily, more fossils were found of it. To be sure, it was a ridiculously large Ornithomimosaur – in fact, given the fact that it was an Ornithomimosaur, a group of distinctively feathered dinosaurs, it is almost certainly one of the largest feathered animals known to date – but it was More than that by a large margin. It was probably around 11 meters long, weighing up to 6.4 tonnes. It had some of the largest forelimbs known of any bipedal dinosaur – only rivaled by Therizinosaurs – and the arms in question are 2.4 meters long. Its skull, only one specimen of it having been found, is honestly weirdly duck-shaped. It was low and narrow, like other Ornithomimosaurs, but with a longer snout than its relatives. This snout was wide and shaped like a spatula – similar to the snouts of duck-billed dinosaurs and ducks alike. There weren’t any teeth in the jaws, which ended in a distinctive beak, and it was turned down, to make it look fairly massive and deep. When you get down to it, Deinocheirus had a ridiculously triangular head. 

By Nix, CC BY-NC 4.0

As for the rest of the body, Deinocheirus had very long and narrow shoulder blades, connected to very pronounced and triangular shoulders. Weirdly enough, compared to the shoulders, Deinocheirus actually had smaller arms than its close relative Ornithomimus – ie, it had a smaller shoulder to arm ratio than its relatives. It had a U-shaped wishbone, which is fascinating since we don’t have the wishbone of other Ornithomimosaurs. Unlike other Ornithomimosaurs, it didn’t have pinched toe bones, so it wasn’t highly adapted for fast movement; it also had very blunt and broad foot claws like those of large Ornithischian dinosaurs. It may have been a bulky animal, but it was also quite narrow – with very tall, straight ribs. It had an S-curved neck, especially given the shape of the skull, which extended back into the oddly indeed shaped back. The spines on the back of Deinocheirus got progressively and progressively longer, until reaching lengths similar to those found on Spinosaurus – indicating that Deinocheirus had a sail or a hump, much like Spinosaurus did. There were interconnecting ligaments on the spines, strengthening it. That sail then lessened as it went down along the tail, until the tail had a very skinny appearance compared to the rest of the body. It had extremely lightweight air bones, through which the respiratory system ran. This also allowed it to be even more lightly built, which aided it in its large size. Interestingly enough, the tail ended in fused vertebrae, like those in Therizinosaurs, Oviraptors, and Birds – indicating it had a pygostyle! 

By Michael B. H., CC BY-SA 3.0

As for feathers, it would have probably been covered in a layer of fluff all over the body. Fancy, pennaceous feathers would have been present on the arms and the end of the tail – in fact, a tail fan would have been attached to that pygostyle and used in display. It may have also had display feathers on the back of the head or even the legs. However, that being said, its large size may indicate a decrease in fluff so that it could stay cool – while it is still most likely that it had distinctive and extensive feathers as in its close relatives, fossil evidence is needed to determine its exact integument situation. 

By Charles Nye

Diet: Deinocheirus was, distinctively, a large herbivore – specializing on water plants and other soft greens that could be shoveled up with that spoon beak. 

By Meig Dickson and Diane Remic

Behavior: Deinocheirus probably spent a good amount of time foraging at or near the water, gathering up water vegetation with its spatulate bill. It also utilized gastroliths – stones that were swallowed to grind up that wet and mushy vegetation in the stomach. This was important and helpful, since it couldn’t do much grinding without teeth in its mouth. It did have a very long and large tongue, which allowed it to pull up extensive amounts of plant material up from the ground. It would use the blunt and short claws of its hands in order to dig up plants from the water – and to decrease resistance as it sucked them up from the swamps. 

By Rebecca Groom

Deinocheirus wasn’t a fast animal – the short and stocky legs meant that it moved slowly through its environment, and used its large size to protect itself against predators instead. It grew extremely rapidly, too, reaching large size before sexual maturity. Sadly, its giant size means that it didn’t have a very large brain compared to its body size – in fact, the ratio in question was more similar to that of sauropods than other theropods. That beings aid, it was similar in shape to birds and troodontids and other birdie theropods, indicating that it still had a decent sense of smell – which is fascinating as it had a good respiratory system as well. As a warm-blooded animal, however, it would have been very active; and as a dinosaur, it probably took care of its young in nests. It is uncertain whether or not it would have lived in social groups, but it certainly wouldn’t have been particularly isolated as an herbivore. 

By José Carlos Cortés

Ecosystem: The Nemegt Formation was a wetland, filled with a wide variety of dinosaurs right before the end of the time of non-avian dinosaurs. The area was filled with large river channels, which created extensive shallow lakes, mudflats, and floodplains – like the modern Okavango Delta in Botswana. There were also thick coniferous forests surrounding the ecosystem, allowing for drier areas to be retreated to in addition to the swampy mess that was the bulk of the environment. Here, many plant-eaters specialized in feeding on water plants – in fact, I often joke that the Nemegt is the Land of Ducks. In addition to Deinocheirus, there were two other Ornithomimosaurs – Gallimimus and Anserimimus – both featuring duck-like beaks for feeding on water plants. Other ducks of the region include Saurolophus, which, as a duck-billed dinosaur, was especially adapted for feeding on soft plant material; and Teviornis, an early ACTUAL duck relative with the appropriate bill. 

By Fraizer

This place also had other dinosaurs that weren’t ducks, of course. There was the large tyrannosaur, Tarbosaurus, which is known to have directly preyed upon Deinocheirus. There were troodontids too, like Tochisaurus, Zanabazar and Borogovia, which would have preyed upon the eggs and young of Gallimimus. There were a million different Oviraptorosaurs, making this also the ecosystem of the Chickenparrots – Avimimus, Elmisaurus, Conchoraptor, Nemegtomaia, Nomingia, and Rinchenia, were all present and feeding on the drier vegetation of the area. There was also the Hesperornithine Brodavis, one of the few freshwater species of Hesperornithines. There were other herbivores too, of course – Pachycephalosaurs like Homalocephale and Prenocephale, ankylosaurs such as Tarchia and Saichania, the titanosaur Nemegtosaurus, and the Therizinosaur Therizinosaurus – which probably all stuck to drier areas of the ecosystem than Deinocheirus. Tarbosaurus wasn’t the only Tyrannosaur, either – there was the smaller Alioramus which would have been more of a nuisance for baby Deinocheirus than the adults. And for other predators, there was the raptor Adasaurus, which may or may not have been a direct descendant of Velociraptor.  As for non-dinosaurs, there was at least one Azdarchid, the small mammal Buginbaatar, and a variety of crocodilians that would have been non-negligible threats to young Deinocheirus. There were also plenty of turtles, which would have been a very noticeable part of the wider ecosystem. 

By Scott Reid

Other: Deinocheirus is such a weird Ornithomimosaur, it gave its name to an entire group of them – these guys were slower than the Ornithomimids, and larger, but still had that general Ostrich-mimic shape. Instead of being lean and fast, they were large and slow. The discovery of the specimens of Deinocheirus that allowed us to actually learn what it looked like was a big one – since, prior to that point, Deinocheirus had been one of the most fascinating mysteries of dinosaur science, as all we had were two giant hands! Because of its large size, duck-like appearance, and above all, nightmare fodder in terms of past legend and current appearance, Deinocheirus has been fondly dubbed as Duck Satan for a makeshift common name. 

~ By Meig Dickson 

Sources Under the Cut 

Diabloceratops eatoni

By Jack Wood

Etymology: Devil Horned Face 

First Described By: Kirkland et al., 2010 

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Ornithischia, Genasauria, Neornithischia, Cerapoda, Marginocephalia, Ceratopsia, Neoceratopsia, Coronosauria, Ceratopsoidea, Ceratopsidae, Centrosaurinae? 

Status: Extinct 

Time and Place: Between 81 and 79 million years ago, in the Campanian of the Late Cretaceous 

Diabloceratops is known from the lower and middle members of the Wahweap Formation of Utah 

Physical Description: Diabloceratops is one of the most completely visually distinctive Ceratopsids – like all members of this very samey group, its body was the same as the rest of them, but its head was distinctive enough to give it a famous name. Like other Ceratopsids, Diabloceratops had four squat legs, a thick torso, and a short tail. It had a long head, with a large crest and a giant beak in the front of its snout, as well as teeth well built for chewing. The interesting thing about this Ceratopsid is that, while it has small brow horns like most early members of this group, it also had two very noticeable horns coming out of its frills – curving away from each other, the left one curving out to the left and the right one curving out to the right. This gave Diabloceratops the very distinctive look of… well, the Christian depiction of Satan. Hence its name, Devil Horned Face! It had a lightly built skull, with a hole seen in earlier Ceratopsians than the later Ceratopsids, and its head was shorter and deeper than later members. The frill of Diabloceratops was kind of weird too – very tall and narrow, rather than wider as in later Ceratopsians. Diabloceratops was primarily scaly all over, though it is possible (especially given how early derived it was) that it had quills or feathery fluff on its tail like earlier Ceratopsians. It was probably about 5.5 meters long from head to tail. 

By Nix, CC BY-NC 4.0

Diet: As a Ceratopsid, Diabloceratops probably fed primarily on plants, though it is possible that it supplemented its diet with meat from time to time for protein. It would focus on low-lying and medium-level plant material, less than a meter in height. 

By Franz Anthony

Behavior: The frill and fancy spikes of Diabloceratops would have been primarily used in sexual display and other types of communication between members of the herd, especially since they were rather small all things considered. That being said, other Ceratopsians would use these features for defense, and it is thus likely that Diabloceratops did too, even though they didn’t evolve for such a purpose. Diabloceratops, like other Ceratopsians, would have been a very social animal, spending most of its life in herds with socially complex behavior. These herds would have aided Diabloceratops in defending itself from the local predator Lythronax, and any other predatory animals that may have attempted to attack it. Like other dinosaurs, Diabloceratops probably would have taken care of its young, and the social group would have aided it in doing so. Being a large herbivore with deadly weapons on its face, Diabloceratops would have been a very aggressive animal, not trusting anything that got too close to it or its family. It is possible that Diabloceratops herds also migrated too and from the Western Interior Seaway, based on the seasonal rainfall. 

By Sam Stanton

Ecosystem: The Wahweap Formation is one of the earliest environments we know of from the charismatic and iconic Late Cretaceous North American faunas – those ecosystems from the Campanian and Maastrichtian which featured Ceratopsians, Hadrosaurs, and Ankylosaurs a plenty, all being preyed upon by terrifying Tyrannosaurs. Weirdly enough, this unique makeup of these ecosystems is unique to North America – while Hadrosaurs could be found elsewhere somewhat, both Tyrannosaurs and Ceratopsids were very rare elsewhere, Ceratopsids especially so. Instead, the world was frequented with many other kinds of large predatory dinosaurs (especially Abelisaurids), and Titanosaurs were some of the most common large herbivores. But I am getting off track – the Wahweap Formation is one of the earliest of these charismatic locations, and as expected, it has some of the earliest members of these groups to branch off, including Diabloceratops. The Wahweap Formation began as a very dry ecosystem, filled with sand and very brief wet seasons; over time, it became a pond ecosystem and – by the time Diabloceratops disappeared – a very fertile system of rivers running in from the Western Interior Seaway. 

By Nathan E. Rogers, used with permission from Studio 252Mya

So, in the time of the earliest part of the formation, Diabloceratops was a living in an extremely seasonally varied environment, as it began to transition to more freshwater being present in later millenia from its earlier dry beginnings. The diversity of the later environments, however, was lacking in the earliest one. Here, Diabloceratops was preyed upon by Lythronax, and while some mammals, turtles, and crocodylomorphs were present, it is entirely possible that the great diversity of mammals and other animals to be found later wasn’t present quite yet. In the middle environment, when the ponds were coming in and things were getting more lush, Lythronax was gone – but now Diabloceratops was accompanied by the Hadrosaur Acristavus, similar to the later Maiasaura. There were many non-dinosaurs too, like turtles, though it is uncertain if the many mammals found in Wahweap are from the middle, lower, or upper parts of this environment.  

By Nix, CC BY-NC 4.0

Interestingly enough, one of Diabloceratops’ closest relatives, Machairoceratops, is known from the upper unit of this formation – indicating that it is possible that Diabloceratops evolved into Machairoceratops, and never really disappeared from the environment at all. 

By José Carlos Cortés

Other: Diabloceratops is usually found to be a Centrosaurine, the group of Ceratopsids with prominent nose horns and frill ornamentation, and usually little to no brow horns. However, a very recent analysis of Ceratopsian relationships found Diabloceratops to be neither a Centrosaurine nor a Chasmosarine (the other group of Ceratopsians, which includes Triceratops and its closest relatives), but rather outside both. Either way, Diabloceratops was a very early Ceratopsids, showing characteristics that are often found in common between both of the major groups of these dinosaurs – and showing how weird their headgear got even early on in their evolution. 

~ By Meig Dickson

Sources Under the Cut 

Saturnalia tupiniquim

By Ripley Cook

Etymology: Named for the Roman festival of Saturn 

First Described By: Langer et al., 1999 

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Sauropodomorpha, Saturnaliidae 

Status: Extinct 

Time and Place: 233.23 million years ago, in the Carnian of the Late Triassic 

Saturnalia is known from the Alemoa Member of the Santa Maria Formation – it is also possibly known from Zimbabwe, but this assignment is dubious 

Physical Description: Saturnalia was probably a very early Prosauropod – aka, those dinosaurs that were more closely related to the large and famous Sauropods than any other kind of dinosaur (the official name for these dinosaurs being Sauropodomorphs). As an early Prosauropod, then, Saturnalia didn’t look very much different from other early dinosaurs – it was small, fluffy, squat, and bipedal. It was so much like other dinosaurs that it is often classified outside of Sauropodomorpha proper – and that continues to be a source of debate for these dinosaurs. In fact, according to some, it’s an early theropod!! More work is clearly needed, but regardless, Saturnalia was about 1.5 meters long and no more than a meter tall. It had a somewhat long neck – but no longer than other early dinosaurs, certainly not proper sauropodomorph length – and a small head. It had short arms, somewhat short legs, and a short tail as well. It was very slight, and had a skull like that of prosauropods, though its legs were more like those of theropods. Overall – a very average looking early dinosaur, and certainly very similar to the early Sauropodomorphs and the early Theropods of the time. 

Diet: Saturnalia probably was an omnivore, feeding on both meat and plant food, at low levels of vegetation and mainly focusing on very small animals. Though it is also possible that it was a carnivore. 

By Rex Chen

Behavior: Saturnalia, regardless of its affinity, would have been a very skittish animal – avoiding predators in its environment at all costs, and running about on its tip-toes in order to avoid danger. It was probably at least somewhat social, given multiple skeletons have been found of it, though of course we cannot be certain of such. Regardless, it would have spent a large portion of its day foraging on food, looking around for leaves to strip from branches and small animals to catch in its mouth. It would have probably taken care of its young, and may have formed family groups to do so. The long-ish neck of Saturnalia would have allowed it to reach deeper into the plantlife in order to grab food out of reach. 

Ecosystem: The Santa Maria Formation is a hotspot of early dinosaur diversity, showcasing especially the initial explosion of Sauropodomorphs after dinosaurs first appeared. This was an extensive floodplain environment, filled with seed ferns and conifers, giving Saturnalia good amounts of cover to protect it from other creatures. This was important, because Saturnalia was far from alone in its home. Here, there were predatory dinosaurs, such as the Herrerasaurid Staurikosaurus and the prosauropod Buriolestes; mystery dinosaurs like Nhandumirim; other early prosauropods like Pampadromaeus and Bagualosaurus; the Lagerpetid Ixalerpeton; the weird Aphanosaur Spondylosoma; large Loricatan predators like Rauisuchus, Procerosuchus, Prestosuchus, Decuriasuchus, and Dagasuchus; large herbivorous Aetosaurs such as Aetobarbakinoides, Aetosauroides, and Polesinesuchus; rhynchosaurs like Hyperodapedon and Brasinorhynchus; mystery reptiles like Barberenasuchus; Proterochampsids like Cerritosaurus, Chanaresuchus, Proterochampsa, and Rhadinosuchus; Erpetosuchids like Pagosvnator; and plenty of synapsids such s Chiniquodon, Candelariodon, Exaeretodon, Protuberum, Santacruzodon, and Trucidocynodon. In short – an extremely diverse and flourishing environment, showcasing the true weirdness that was the Triassic period. 

By Nobu Tamura, CC BY-SA 4.0

Other: Was Saturnalia a theropod or a prosauropod? The jury is still out. Its back half looks much like that of a theropod, but its head? Similar to prosauropods. The most recent analysis has it as a sauropodomorph – probably – but people still debate, and arguments continue to go on. It is often considered a part of a bigger group of dinosaurs including animals like Guaibasaurus, but some of these animals in recent studies have been found as prosauropods, and some as theropods, breaking up the group. So, the scientists continue to debate, and the exact nature of Saturnalia remains a mystery – but, for now, we can probably still call it a Sauropodomorph, along with Pampadromaeus. 

~ By Meig Dickson

Sources Under the Cut 

Nasutoceratops titusi

By Scott Reid

Etymology: Large-Nosed Horned-Face

First Described By: Sampson et al., 2013

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Ornithischia, Genasauria, Neornithischia, Cerapoda, Marginocephalia, Ceratopsia, Neoceratopsia, Coronosauria, Ceratopsoidea, Ceratopsidae, Centrosaurinae, Nasutoceratopsini 

Status: Extinct

Time and Place: Between 76 and 75.6 million years ago, in the Campanian age of the Late Cretaceous

Nasutoceratops is known from the middle member of the Kaiparowits Formation in Utah

Physical Description: Nasutoceratops is a Ceratopsian – so, as with all Ceratopsians, it has an extremely distinctive head! Like other Ceratopsians, it would have been around 5 meters long or so, and had a very bulky body with a short, skinny tail. The legs of this dinosaur – as in others of its kind – were short, bulky, and had very padded and thick toes that made running easy for this animal. The really distinctive aspects of this dinosaur, however, were in its head – again, as in other Ceratopsians, which might as well all be Mr. Potato Heads with the different combinations of horns and frills as the exchangeable parts of the classic toy. Nasutaceratops sported a short frill, a short and high snout, and distinctively long horns. The horns on its brow were more horizontal than most, but they curved inward like those found on modern cattle! The nostril did not feature a horn, but was very high and ridged instead. Interestingly enough, there were extensive cavities in this rounded nose that may have been pneumatic, giving Nasutoceratops a very unique trait compared to other Ceratopsians. It had a very thickly overlapping upper jaw, which would have made it somewhat less flexible than other Ceratopsians. The frill had small round osteoderms all around the edge, and there isn’t a notch on the frill like in other Ceratopsians. As in its relatives, Nasutoceratops would have probably been primarily scaly, though it may have had feather-quills on the edge of its tail or elsewhere on its body. The frill would have probably been brightly colored, for display.

By José Carlos Cortés

Diet: Nasutoceratops would have primarily been an herbivore, feeding on low-lying and medium-level leaves and other plant material, all less than one meter tall.

Behavior: Nasutoceratops, like other Ceratopsians, would have been a very social creatures! These dinosaurs would have spent a lot of time together roaming their home in large herds, and used their frills and fancy horns to display to one another for communication and mating displays. This points back to their fairly complicated social groupings, where the young would have been protected by the adults from oncoming danger. The horns would have also been useful in telling apart Nasutaceratops from other dinosaurs that lived with it, such as the Chasmosaurine Ceratopsian Kosmoceratops. Like other dinosaurs, it would have been warm-blooded, and thus needed to spend a good chunk of the day finding food. It also may have fought with its horns, though that’s somewhat more controversial, especially given their odd shape – though a combination of the bumpy nose and horns . These horns may have had sheaths of fingernail material (keratin) over them, making them longer, but probably not more available for fighting. The colors of the frill may have been able to change, giving even more communication ability. These structures – the frills and horns – wouldn’t have been prominent in baby Nasutoceratops, but grew with the animal as it aged into sexual maturity. Nasutoceratops would have taken care of its young, which would eventually join the herd with the adults.

By Kathy Neenan, CC BY-SA 4.0

Ecosystem: Nasutoceratops lived in the Kaiparowits Formation, which would have been a very muddy jungle ecosystem, with a wide variety of animals living very near the Western Interior Seaway. A variety of swamps, ponds, and lakes frequented the entire area, which was surrounded on its other side by highlands and mountains, enclosing it against the sea. It was a very wet and humid environment, allowing for high animal diversity. Among those that lived with Nasutoceratops include other Ceratopsians like Kosmoceratops and Utahceratops, hadrosaurs like Gryposaurus and Parasaurolophus, the ankylosaur Akainacephalus, the Troodontid Talos, the Ornithomimid Ornithomimus, the Oviraptor Hagryphus, and the opposite bird Mirarce! That being said, the main predator of Nasutoceratops would definitely have been the local Tyrannosaur, Teratophoneus. There were also a variety of mammals, turtles, and Neosuchians in the environment, which all took advantage of the wet swampy conditions.

By Ripley Cook

Other: Nasutoceratops was a Centrosaurine, those Ceratopsians more closely related to the likes of Styracosaurus than to Triceratops. Interestingly enough, these Ceratopsians tend to do more weird stuff with their noses – usually giant horns, but Nasutoceratops seems to have gone for a more lightweight option. In fact, Nasutoceratops gave its name to a whole group of these animals, which retained the brow horns of the ancestral ceratopsians (where other Centrosaurines lost them).

~ By Meig Dickson

Sources Under the Cut 

Chaoyangsaurus youngi

By Jack Wood

Etymology: Reptile from Chaoyang 

First Described By: Zhao, Cheng, & Xu; 1999 

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Ornithischia, Genasauria, Neornithischia, Cerapoda, Marginocephalia, Ceratopsia, Chaoyangsauridae  

Status: Extinct 

Time and Place: Sometime between 151 and 146 million years ago, in the Tithonian of the Late Jurassic 

Chaoyangsaurus is known from the Tuchengzi Formation of Liaoning, China 

Physical Description: Chaoyangsaurus was a small, bipedal herbivore – like so many other dinosaurs from the time – but differed from its close cousins in some important ways. Namely, it had a distinct top beak to go with the lower beak, that was slightly hooked; and in addition to that, it had a ridge on the back of its head. These two factors signal out the little guy for what it was – one of the earliest known Ceratopsians! This famed, iconic group of dinosaurs really got their start from such humble beginnings as Chaoyangsaurus. It would have had longer legs than arms, and run about bipedally – with a slightly larger head for the rest of its body. It may have been completely fluffy – like other small bipedal herbivores – or had distinctive quills on its tail, like it’s later relative Psittacosaurus. Either way, it would have had fluff in some form. Chaoyangsaurus was quite small, only about a meter long. 

Diet: As a small Ornithischian, Chaoyangsaurus would have primarily fed upon low-lying plants such as ferns. 

By Nobu Tamura, CC BY 3.0

Behavior: Chaoyangsaurus would have been a fairly skittish animal, running about in its environment attempting to avoid predators with speed rather than defense. Though that beak would have been good at snipping off tough vegetation, it wouldn’t have been the best in defense from larger predators. However, that ridge on the back of its skull may have provided extra defense for the head if something knocked into it. Chaoyangsaurus was probably at least a little social – since most small bipedal Ornithischians seemed to be so – using calls and notice from the other members of the flock to escape predators. The quills it may have had would have been good for display, so it could signal to each other that they were looking for mates and the like. It would have taken care of its young, which would have been even smaller! Too cute to process, really! 

Ecosystem: Chaoyangsaurus lived in the Tuchengzi Environment, a late Jurassic environment from far western China. In fact, it is a transitional environment between the famed Daohugou Biota – a showcase for small, fluffy animals of the Mid Jurassic – and the even more famed Jehol Biota – a showcase for the small, fluffy animals of the Early Cretaceous. This transitional environment was not as lush, not as well preserved, and extremely dry – seemingly, semi-arid. This dry environment lead to the extinction of the unique and beautiful Daohugou auna. It was also more poorly preserved at this time, though clearly dinosaurs and other life forms were around (as Chaoyangsaurus was). Chaoyangosaurus was probably primarily preyed upon by a mysterious Raptor, from which we only have footprints; there was also a small general theropod present, and the small pterosaur Orientognathus. This environment would eventually grow lush again – and with it, small fluffy creatures would explode into amazing abundance once more. 

By José Carlos Cortés

Other: Chaoyangsaurus shows the start animals like Triceratops and company really had – as these small, nippy bipedal creatures, running around in the undergrowth of the Jurassic and Early Cretaceous, trying to escape the larger predators! The quadrupedal stance, large frills, and horns would come much later – the giant horns, not until the Late Cretaceous. 

~ By Meig Dickson 

Sources Under the Cut 

Pisanosaurus mertii

By José Carlos Cortés

Etymology: Pisano’s Reptile 

First Described By: Casamiquela, 1967 

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Silesauridae? 

Status: Extinct 

Time and Place: 231.4 million years ago, in the Carnian of the Late Triassic 

Pisanosaurus is known from the Cancha de Bochas Member of the Ischigualasto Formation in San Juan Argentina. 

Physical Description: If a Silesaurid – as is currently thought – Pisanosaurus would have been a small, slender, and quadrupedal animal, only about 1 meter in length. It had an open hip socket, like dinosaurs, which may point to a very interesting phylogenetic position (see the Other section below). It had very elongated bones in its hands, and its upper hips were weirdly wide as well. Beyond that, we don’t know much about with Pisanosaurus may have looked like. It seems logical to suppose it would have had a small head with a little beak in the front of the mouth – as both Silesaurids and early Ornithischians (the other hypothesis for the type of creature Pisanosaurus was) have such structures for snipping off plant material. Given its small size, Pisanosaurus – like all other early members of the group of reptiles that would later include birds (Avemetatarsalia) – would have been covered with fluff all over its body. If Pisanosaurus was an early Ornithischian and not a Silesaurid, it would have been bipedal, with short forelimbs not used in locomotion. 

Diet: Either way, Pisanosaurus would have been an herbivore, eating low-lying vegetation in its densely forested home. 

Behavior: As a small, lithe herbivore, Pisanosaurus would have been very skittish – running at the slightest sign of danger, making sure to avoid the many large predators it shared a home with. It probably wouldn’t have been very social – given it wasn’t very abundant! – but it may have foraged in large groups of mixed herbivores, sticking together to rely on each other in the event of danger. This reliance would have allowed bulkier herbivores to notice and react to danger quicker (since the small lithe ones like Pisanosaurus would have already been running away) – and the smaller ones would have had large, bulky roadblocks to stop the approach of predators. As an early dinosaur, it most likely partook in some sort of care of its young, though of course, we do not know what. 

(As an Ornithischian) by Michael B. H., CC BY-SA 3.0

Ecosystem: The Ischigualasto Environment is one of the more famous ecosystems of the Late Triassic – due to it being a hotbed of early dinosaur discoveries, including some of the earliest potential members of the group. In fact, it is such an important environment that today the rock formation is considered a UNESCO World Heritage Site. It was an extensive series of rivers channeling through a large floodplain, erring towards the wetter side of the scale – mud was the name of the game, and there was a wide variety of plant material present, including a dense conifer forest, ferns, and horsetails. It did experience seasonal rainfall, with possible times of extremely heavy precipitation. Occasionally, everything would be buried in volcanic ash – leading to the beautiful preservation of the environment. 

Pisanosaurus wasn’t the only Silesaurid here – there was also Ignotosaurus, the slender and small Silesaurid. There were also famous early dinosaurs such as Eoraptor – the small, bipedal early Saurischian(?), Herrerasaurus and Sanjuansaurus, the large taxonomically-confusing predators, and Chromogisaurus, one of the earliest known “prosauropods.” Of course, this being the Triassic, dinosaurs were only a small part of the ecosystem. The Ischigualasto – like most places of the time period – was absolutely lousy with other archosauriformes! Non-Dinosaurian Archosauriformes were extensively diverse at this time, making up a large chunk of the “large charismatic land animal” roles. There was Aetosauroides, an Aetosaur (sort of like a cross between an ankylosaur, an ant-eater, and a crocodile), Proterochampsa and Pseudochampsa – crocodilian-like creatures that were actually equally closely related to crocodiles and dinosaurs – both frequented the rivers of the environment. Saurosuchus, a large and bulky stem-croc, would have been a huge pain in the rear for herbivores like Pisanosaurus. Sillosuchus was a weird stem-croc, bipedal and strangely dinosaur like – with even, potentially, a beak – but utterly scaly, and bulky in stature! There was also Venaticosuchus, an Ornithosuchid (one of the most basal groups of stem-crocs), and Trialestes – a fast moving stem-croc, and one of the earliest Crocodylomorphs (the group of crocodilians and their closest relatives). 

(Without Feathers) by Nobu Tamura, CC BY-SA 4.0

It being the Triassic, this wasn’t an environment free of non-reptiles! Temnospondyls – large carnivorous amphibians – were crawling about; as were a variety of Synapsids. Small, carnivorous dog-shaped cynodonts like Chiniquodon would have directly competed with the local dinosaurs; they even grew to be quite large and fast, like in Diegocanis and Ecteninion. They also came in large, bulky herbivorous forms, like Exaeretodon. Dicynodonts were present too, with their strange pig-like appearance: Ischigualastia was a common synapsid on the floodplains of Pisanosaurus’ home. In short, Pisanosaurus was surrounded with a cast of characters showcasing some – but certainly not all – of the weirdness that the Triassic  had to offer. 

Other: What Is Pisanosaurus? Back in the day, Pisanosaurus was a famous creature for being one of the earliest “Ornithischian” dinosaurs – one of two major groups of dinosaurs, famous for including such later iconic members as Stegosaurus and Triceratops. In fact, for the longest time, Pisanosaurus was… the only Ornithischian known from the Triassic. This is odd, to say the least – there are dozens of Triassic dinosaurs known, they’re just all from the other group, the Saurischians (containing such iconic later forms as Apatosaurus, Tyrannosaurus, and… all birds). So, for the longest time, Pisanosaurus stood as a focal point of dinosaur research – an important piece of the puzzle of the origin of this elusive, but important group. 

By Nix

Except it isn’t an Ornithischian. Lately, studies have shown time and time again that Pisanosaurus actually more closely resembles the Silesaurids – a group of almost dinosaurs that were quadrupedal, active herbivores living around the world at the time of the Triassic, before going extinct at the end-Triassic extinction. This would make its appearance much different than what a “basal Ornithischian” would suggest – and, of course, the fact that Pisanosaurus is known from only a single fragmented skeleton does not make solving this problem much easier. Weirdly enough, there are some hypotheses which suggest that Silesaurids are… the earliest Ornithischians, (as per Pisanosaurus having an open hip-socket), representing a weird side-branch of the group from the Triassic. As this hypothesis gains traction, it may become increasingly true that Pisanosaurus was a Silesaurid – it was just also an early Ornithischian. Only time will tell in the solving of this mystery – for now, we must wait for more evidence. 

~ By Meig Dickson

Sources Under the Cut