Coelurosauria

Coelurosaurs Temporal range: Ma[1] PreꞒ Ꞓ O S D C P T J K Pg N Possible Early Jurassic record[2]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Clade:	Avetheropoda
Clade:	Coelurosauria von Huene, 1914
Included taxa
†Aratasaurus †Bicentenaria †Juravenator †Vayuraptor[3] †Xinjiangovenator[4] †Ornitholestes †Zuolong †Coeluridae †Tyrannosauroidea †Compsognathidae (possibly polyphyletic) Maniraptoriformes †Ornithomimosauria †Maniraptora Incertae sedis †Asiamericana †Aniksosaurus †Chilantaisaurus? †Gasosaurus?[5] †Gualicho? †Iliosuchus? †Lourinhanosaurus?[6] †Phaedrolosaurus[4] †Richardoestesia[4] †Sciurumimus?[7] †Shanyangosaurus †Teinurosaurus?[4] †Megaraptora?

Coelurosauria (

Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids, tyrannosaurs, ornithomimosaurs, and maniraptorans; Maniraptora includes birds, the only known dinosaur group alive today.^[10]

Most

The studying of anatomical traits in coelurosaurs indicates that the last common ancestor had evolved the ability to eat and digest plant matter, adapting to an omnivorous diet, an ability that could be a major contributor to the clade's success. Later groups would hold on to the omnivory, while others specialized in various directions, becoming insectivorous (Alvarezsauridae), herbivorous (Therizinosauridae) and carnivorous (Tyrannosauroidea and Dromaeosauridae).^[12] The group includes some of the largest (Tyrannosaurus) and smallest (Microraptor, Parvicursor) carnivorous dinosaurs ever discovered. Characteristics that distinguish coelurosaurs include:

• a sacrum (series of vertebrae that attach to the hips) longer than in other dinosaurs
• a tail stiffened towards the tip
• a bowed ulna (lower arm bone).
• a tibia (lower leg bone) that is longer than the femur (upper leg bone)

Integument

Fossil evidence shows that the skin of even the most primitive coelurosaurs was covered primarily in

Though once thought to be a feature exclusive to coelurosaurs, feathers or feather-like structures are also known in some ornithischian dinosaurs (like Tianyulong and Kulindadromeus), and in pterosaurs. Though it is unknown whether these are related to true feathers, recent analysis has suggested that the feather-like integument found in ornithischians may have evolved independently of coelurosaurs but this was estimated by assuming that primitive pterosaurs had scales.^[13] In 2018, two anurognathid specimens were found to have integumentary structures similar to protofeathers. Based on phylogenetic analysis, protofeathers would have had a common origin with avemetatarsalians.^[14][15]

Nervous system and senses

Although rare, complete casts of theropod

There is consensus among paleontologists that birds are descended from coelurosaurs. Under modern cladistical definitions, birds are considered the only living lineage of coelurosaurs. Birds are classified by most paleontologists as belonging to the subgroup Maniraptora.^[19]

A portion of a tail belonging to a juvenile coelurosaur was found in 2015, inside of a piece of amber.

Classification

The

Within Coelurosauria exists a slightly less inclusive clade named Tyrannoraptora. This clade was defined by Sereno (1999) as "Tyrannosaurus rex, Passer domesticus (the house sparrow), their last common ancestor, and all of its descendants".^[20] As tyrannosauroids are considered to be the most basal large group within Coelurosauria, this means that the common ancestor of tyrannosauroids and birds was an even more basal coelurosaurian. As a result, almost all coelurosaurians are also tyrannoraptorans, with the only exceptions being particularly basal species such as Zuolong salleei or Sciurumimus albersdoerferi.

Several recently-named clades have been proposed to define the structure of Coelurosauria crownward of basal groups such as tyrannosauroids and compsognathids. Maniraptoromorpha, defined by Andrea Cau in 2018, includes all coelurosaurians more closely related to birds than to tyrannosauroids. Cau stated that the synapomorphies of the clade included "Keel or carinae in the postaxial cervical centra, absence of hyposphene-hypantra in caudal vertebrae (reversal to the plesiomorphic theropodan condition), a prominent dorsomedial process on the semilunate carpal, a convex ventral margin of the pubic foot, a subrectangular distal end of tibia and a sulcus along the posterior margin of the proximal end of fibula."^[21] Another proposed clade is Neocoelurosauria, erected by Hendrickx, Mateus, Araújo and Choiniere (2019),^[22] They define it as "the clade Compsognathidae + Maniraptoriformes", which can be more or less inclusive than Maniraptoromorpha depending on the topology.

The following family tree illustrates a synthesis of the relationships of the major coelurosaurian groups based on various studies conducted in the 2010s.^[23]

"Coelurosaurus"

"Coelurosaurus" is an

• Feathered dinosaurs
• Origin of birds
• List of fossil birds

References

References

• ISBN 978-0-253-34595-0
  .
• Larsson, H.C.E. (2001). "Endocranial anatomy of Carcharodontosaurus saharicus (Theropoda: Allosauroidea) and its implications for theropod brain evolution". In Tanke, D. H.; Carpenter, K.; Skrepnick, M. W. (eds.). Mesozoic Vertebrate Life. Indiana University Press. pp. 19–33.
• Mayr, G., B. Pohl & D.S. Peters (2005). "A well-preserved Archaeopteryx specimen with theropod features". Science, 310(5753): 1483–1486.
• George Olshevsky. "Re: What are these dinosaurs". Archived from the original on 2007-12-09. Retrieved 2007-01-29. (on "Coelurosaurus")
• Padian, K (2004). "Basal Avialae". In Weishampel, D.B.; Dodson, P.; Osmólska, H. (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 210–231.
  ISBN 0-520-24209-2
  .
• Senter, P. (2007). "A new look at the phylogeny of Coelurosauria (Dinosauria: Theropoda)." Journal of Systematic Palaeontology, (
  doi:10.1017/S1477201907002143
  ).
• Zanno, L.E., Gillette, D.D., Albright, L.B., and Titus, A.L. (2009). "A new North American therizinosaurid and the role of herbivory in 'predatory' dinosaur evolution." Proceedings of the Royal Society B, Published online before print July 15, 2009,
  doi:10.1098/rspb.2009.1029
  .
• First Dinosaur Tail Found Preserved in Amber. National Geographic, December 8, 2016.

External links

Look up Coelurosauria in Wiktionary, the free dictionary.

• Paleobiology Database: Coelurosauria
• The Major Groups of Coelurosaurs
• Palaeos: Coelurosauria
• Tree of Life Web: Coelurosauria