Caenagnathasia martinsoni

By José Carlos Cortés

Etymology: Recent Jaw from Asia

First Described By: Currie et al., 1994

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Maniraptora, Pennaraptora, Oviraptorosauria, Caenagnathoidea, Caenagnathidae, Elmisaurinae

Status: Extinct

Time and Place: Between 92 and 90 million years ago, in the Turonian of the Late Cretaceous 

Caenagnathasia is known from the Bissekty Formation of Uzbekistan 

Physical Description: Caenagnathasia was a Chickenparrot, and of the kind with particularly long and shallow jaws, with complex ridges inside. Caenagnathids also were more lightly built than Oviraptorids, with more hollow bones, more slender arms and long, gracile legs. They also weren’t very adapted for running as in other Oviraptorosaurs. Caenagnathasia, however, is not very well known. It’s known from a few jaws from a few individuals, as well as some vertebrae and a femur. We do know that Caenagnathasia is one of the smallest known oviraptorosaurs, and one of the smallest non-avian dinosaurs on the whole. It probably was about 0.61 meters long, and weighed 1.4 kilograms. Other than that, it probably would have resembled other oviraptorosaurs in general – fully feathered and bird like, with extensive wings, a tail fan, a beak, and long legs. It also was probably one of the more basal Caenagnathids.

Diet: Like other Oviraptorosaurs, Caenagnathasia was probably an omnivore.

Behavior: It is likely that Caenagnathasia behaved similarly to other Oviraptorosaurs, though we have no proof either way on that score. It probably would have taken care of its young, creating a large nest with eggs laid around the edge. Caenagnathasia would then sit in the center of the nest and use its wings to keep the eggs warm, like modern birds. These eggs were ovular and elongated, and potentially teal or turquoise in color. Caenagnathasia would have also been an an active, warm-blooded animal, using its wings to communicate with other members of the species and in sexual display. It also would have probably been opportunistic in terms of food eaten, feeding on whatever it could get its wings on. 

By Ripley Cook

Ecosystem: The Bissekty Formation was a diverse Middle Cretaceous seashore, filled with brackish swamps and braided rivers along the coast. It probably would have been filled with horsetails, cycads, ferns, and early flowering plants, though no plant fossils are known from the formation. There were a variety of animals in this ecosystem, especially many transitional forms to the iconic dinosaurs of the Late Cretaceous. There was Turanoceratops, a forerunner of Ceratopsids like Triceratops; Levnesovia, an almost-hadrosaurid, as well as other ornithopods Gilmoreosaurus and Cionodon; Bissektipelta, an ankylosaur; Timurlengia, a transitional Tyrannosaurid; Itemirus, one of the earliest known possible Velociraptorines; the troodontids Urbacodon and Euronychodon, and a variety of early birds such as Platanavis, Zhyraornis, and opposite birds like Abavornis, Catenoleimus, Explorornis, Incolornis, Kizylkumavis, Kuszholia, Lenesornis, and Sazavis. There was also a probable Ornithomimosaur that has not yet been named.

Non-dinosaurs were also present, including the huge pterosaur Azhdarcho, many different kinds of fish, some turtles, amphibians, and even sharks that were adapted to the ample brackish water. There were a lot of crocodylomorphs, too, like Zhyrasuchus, Zholsuchus, Kansajsuchus, and an alligatoroid, Tadzhikosuchus. There were also a lot of weird Iguanas, and early mammals as well – herbivorous Zhelestids, burrowing Asiorhyctitherians, insectivorous Zalambdalestids, almost-marsupials, and rodent-like Cimolodonts. This is surely an exciting ecosystem for further research, as it showcases a transition from the Early Cretaceous, to the Late.

Other:

~ By Meig Dickson

Sources under the Cut 

Microvenator celer

By Ripley Cook

Etymology: Small Hunter

First Described By: Ostrom, 1970

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Maniraptora, Pennaraptora, Oviraptorosauria, Caenagnathoidea, Caenagnathidae

Status: Extinct

Time and Place: Between 115 and 105 million years ago, from the Aptian to the Albian ages of the Early Cretaceous 

Microvenator is known from the Cloverly Formation of Montana and Wyoming; specifically the Little Sheep and Himes members of the Formation 

Physical Description: Microvenator was an Oviraptorosaur – aka, a Chickenparrot – one closely related to the later Anzu from the Hell Creek formation at the end of the Cretaceous. Still, the main remains it is known from are a juvenile, which actually lead to its name – prior to further study, we thought the juvenile was as big as it got, and thus named it for its small size. As such, Microvenator probably got much bigger than the original estimates – while the juvenile was about 1.2 meters long, an adult would probably be around 3 meters long.

As a chickenparrot, Microvenator would have been fairly squat in body, and it had a shorter tail than your average dinosaur – but, as an earlier member of the group, it didn’t have a pygostyle like some of the later species. It had long arms and moderate length legs, and was covered in feathers – especially notable wings on the arms and a tail fan on the tail. It probably had a large beak, as well, but little of the skull is known.

Diet: As an Oviraptorosaur, Microvenator probably had an omnivorous diet, eating a wide variety of food, especially plants. 

By Scott Reid

Behavior: Though Microvenator isn’t particularly well-known, it probably behaved similarly to its close relatives, including in taking care of its young. Oviraptorosaurs are known to have been great parents, creating large nests with eggs laid around the edge, laid from a single oviduct. Microvenator would have then sat in the center of the nest, and used its wings to keep the eggs warm – much like how birds do so today. Microvenator laid ovular, elongated eggs, which were probably turquoise or teal in color.

Microvenator was a feathered, warm-blooded animal, and thus very active in its environment and with its behavior; using its feathers to display to other members of the species for sex and communication – and its large wings and tail fan would have been excellent for these activities. As an omnivore, it would have been an opportunistic animal as it looked around its environment for food.

Ecosystem: The Cloverly Formation was one of many distinctive “middle” Cretaceous environments in Western North America, a transition between the iconic Late Jurassic and Late Cretaceous faunas of the area. Here, the Western Interior Seaway was growing in Microvenator’s backyard, which was mainly a floodplain and river system with extensive flooding that buried many animals at a time. These plains were forested, covered with many conifers and cycads. 

By José Carlos Cortés

The earlier environment, the Little Sheep ecosystem, was much muddier and less associated with the sea than later times. Here, Microvenator lived with the ankylosaur Sauropelta, the ornithopod Tenontosaurus, the small fast-moving herbivore Zephyrosaurus, and the medium-sized theropod Deinonychus. There was an unnamed sauropod as well, as well as lungfish, sharks, fish, frogs, salamanders, crocodilians, and turtles – and a lot of types of mammals and lizards, which would have been decent food for Microvenator in a pinch.

The later Himes ecosystem was sandier, and more associated with the sea as it grew into North America. Microvenator still lived alongside Deinonychus, Sauropelta, and Tenontosaurus, but also the large sauropod Sauroposeidon and the poorly known Rugocaudai; a new nodosaur, Tatankacephalus, and the large predator Acrocanthosaurus which would have been a major threat to Microvenator. There also may have been a proto-bird present in the ecosystem, along with many kinds of lizards, frogs, salamanders, crocodilians, turtles, fish, sharks, and mammals.

Other: Microvenator is the oldest known Oviraptorosaur from North America!

~ By Meig Dickson

Sources

Mackovicky, Peter J., Sues, Hans-Dieter. (1998). “Anatomy and phylogenetic relationships of the Theropod Dinosaur Microvenator celer from the Lower Cretaceous of Montana” American Museum Novitates. Number 3240, 27pp. 27 August 1998.

Maxwell, W. D. 1993. Neonate dinosaur remains and dinosaur eggshell from the Lower Cretaceous Cloverly Formation, Montana. Journal of Vertebrate Paleontology 13(3, suppl.):49A

Norell, M.A., Gaffney, E.S., and Dingus, L. 1995. Discovering Dinosaurs in the American Museum of Natural History. Alfred A. Knopf, Inc.:New York, 204 p.

Oreska, M. P. J., M. T. Carrano, and K. M. Dzikiewicz. 2013. Vertebrate paleontology of the Cloverly Formation (Lower Cretaceous), I: faunal composition, biogeographic relationships, and sampling. Journal of Vertebrate Paleontology 33(2):264-292 [

Ostrom, J. H. 1970. Stratigraphy and paleontology of the Cloverly Formation (Lower Cretaceous) of the Bighorn Basin area, Wyoming and Montana. Peabody Museum Bulletin 35:1-234

Sato, T., Y. Cheng, X. Wu, D. K. Zelenitsky, Y. Hsaiao. 2005. A pair of shelled eggs inside a female dinosaur. Science 308 (5720): 375.

Varricchio, D. J. 2001. Late Cretaceous oviraptorosaur (Theropoda) dinosaurs from Montana. pp. 42–57 in D. H. Tanke and K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Indianapolis, Indiana.

Wiemann, J., T.-R. Yang, P. N. Sander, M. Schneider, M. Engeser, S. Kath-Schorr, C. E. Müller, P. M. Sander. 2017. Dinosaur origin of egg color: oviraptors laid blue-green eggs. PeerJ 5: e3706.

Luoyanggia liudianensis

By Scott Reid

Etymology: From Luoyang

First Described By: Lü et al., 2009

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Maniraptora, Pennaraptora, Oviraptorosauria, Caenagnathoidea, Oviraptoridae

Status: Extinct

Time and Place: Sometime around 113 million years ago, at the Aptian to Albian boundary in the Early Cretaceous 

Luoyanggia is known from the Haoling Formation of Henan Province, China 

Physical Description: Luoyanggia is an Oviraptor, aka a Chickenparrot – a group of odd birdie dinosaurs with large parrot-esque beaks and squat, chicken-like bodies. Luoyanggia itself is known from only portions of the skeleton, so it’s difficult to say for sure what it would have looked like exactly. However, it resembles Oviraptor in general, one of the more famous Oviraptorids, apart from not having a downturned jaw and having a V-shaped middle of the mouth. This gave it a fairly distinctive looking head. It also had a differently shaped hip from other Oviraptors. In general, it would have resembled other Oviraptors in having a long neck, a fairly large looking head, a squat body, medium-sized wings, a short tail with a tail fan sticking off of it, and average length legs. It was probably around 1.5 meters in length, making it fairly small for a non-avian dinosaur.

As an Oviraptorosaur, Luoyanggia would have been covered in feathers, including advanced (but not quite bird-like) wings, and a tail fan connected to a pygostyle. Pygostyles are fused, shortened tail bones seen in modern birds and Oviraptorosaurs. This structure evolved independently in both groups and is used to move the tail in more complicated ways, such as in sexual displays and in flight. It is possible that Luoyanggia also had some sort of crest on its head, though none has been preserved.

Diet: Luoyanggia would have been omnivorous, eating a wide variety of food material, though primarily feeding on plants rather than meat.   

By Ripley Cook

Behavior: Though Luoyanggia is not well known, we can glean some of its behavior based on its close relatives. Oviraptorosaurs such as Luoyanggia are known to have taken care of their young extensively, creating large nests with eggs laid around the edge, from a single oviduct. Luoyanggia would then have sat in the center of the nest, and used its wings to keep the eggs warm. This brooding method is very similar to those employed by modern birds. The eggs of Luoyanggia would have been elongated and ovular, rather than small and round. It is also possible that the eggs may have been colored as well, potentially a deep blueish green.

As a feathered, warm-blooded animal, Luoyanggia would have been fairly active in its environment, and probably would have used its feathers not just to cover eggs, but also to display to other members of the species – both by using the tail fan in sexual display, as well as the wings. The wings were not large enough or complex enough, however, to be used on behaviors as seen in Dromaeosaurs and even more birdie dinosaurs.  

As an omnivore, Luoyanggia would have been partially opportunistic, looking in its environment for any possible source of food.

Ecosystem: Luoyanggia lived in a fairly muddy environment, and was probably the site of some sort of freshwater ecosystem, though what specifically is not entirely clear. A swamp or lake seems fairly likely. Other dinosaurs are known from the formation such as the titanosaur Xianshanosaurus, the almost-titanosaurs Yunmenglong, Huanghetitan, and Ruyangosaurus, the ankylosaur Zhongyuansaurus, and a potential large theropod that would have been the main predator of Luoyanggia.

Other: Luoyanggia has never been properly analyzed in a phylogenetic study, so its position as an Oviraptorid is somewhat suspect.

~ By Meig Dickson

Sources 

Holtz, T. R., L. V. Rey. 2007. Dinosaurs: The Most Complete, Up-To-Date Encyclopedia for Dinosaur Lovers of All Ages. New York: Random House.

Longrich, N. R., P. J. Currie, D. Zhi-Ming. 2010. A new oviraptorid (Dinosauria: Theropoda) from the Upper Cretaceous of Bayan Mandahu, Inner Mongolia. Palaeontology 53 (5): 945 – 960.

Lü, J., L. Xu, X. Jiang, S. Jia, M. Li, C. Yuan, X. Zhang, Q. Ji. 2009. A preliminary report on the new dinosaurian fauna from the Cretaceous of the Ruyang Basin, Henan Province of Central China. Journal of the Paleontological Society of Korea 25: 43 – 56.

Sato, T., Y. Cheng, X. Wu, D. K. Zelenitsky, Y. Hsaiao. 2005. A pair of shelled eggs inside a female dinosaur. Science 308 (5720): 375.

Wiemann, J., T.-R. Yang, P. N. Sander, M. Schneider, M. Engeser, S. Kath-Schorr, C. E. Müller, P. M. Sander. 2017. Dinosaur origin of egg color: oviraptors laid blue-green eggs. PeerJ 5: e3706.

Xu, L., Z. C. Pan, Z. H. Wang, X. L. Zhang, S. H. Jia, J. C. Lü, B. L. Jiang. 2012. Discovery and significance of the Cretaceous System in Ruyang Basin, Henan Province. Geological Review 58: 601 – 613