COELUROSAURIA

(Redirected from Coelurosaur)
: ''For the prehistoric gliding reptile, see Coelurosauravus.''
'Coelurosauria' is a diverse group of theropod dinosaurs that includes a number of subgroups, such as Tyrannosauroidea, Ornithomimosauria, and Maniraptora.

Contents

Description

Classification

Traditional 'Coelurosaurs'

Taxonomy

Phylogeny

"Coelurosaurus"

References

External links

Description

Coelurosaur characteristics included a sacrum (series of vertebrae that attach to the hips) longer than in other dinosaurs, a tail stiffened towards the tip, and a bowed ulna (lower arm bone). The tibia (lower leg bone) is also characteristically longer than the femur (upper leg bone) in coelurosaurs. Fossil evidence shows that most coelurosaurs were probably feathered. Prum and Brush stated in a 2002 paper that feathers "originated in a lineage of coelurosaurian theropod dinosaurs including both ''Sinosauropteryx'' and birds", and that feathers probably did not exist in more primitive theropod groups, like "allosauroids, ceratosaurids, and coelophysids."Prum, R., and Brush, A.H. (2002). "The evolutionary origin and diversification of feathers". ''The Quarterly Review of Biology'', '77': 261-295. Thus, feathers are trait of advanced theropods (i.e., coelurosaurs), and probably originated in the most primitive members of this group.
Additionally, fossilized traces of feathers have been identified from at least one species in almost every coelurosaur lineage. Feathers are known from compsognathids, tyrannosauroids, oviraptorosaurians, therizinosaurians, alvarezsaurids, dromaeosaurids, and troodontids. All known specimens in the family Scansoriopterygidae are also known from feather-bearing fossils. To date, the only group of coelurosaurs which have not shown direct evidence of feathers are the ornithomimosaurians.
Most coelurosaurs were bipedal predators and the group includes some of the largest (''Tyrannosaurus'') and smallest (''Microraptor'', ''Parvicursor'') carnivorous dinosaurs discovered thus far. Modern birds are classified by most palaeontologists (but not by all ornithologists^[1]) as an extant group of coelurosaurs (in the subgroup Maniraptora).^[2]

Classification

The coelurosaurs have proven to be an incredibly diverse group since they were originally named as an infraorder (complimenting the Infraorder Carnosauria). After the 1960s, when several distinctive lineages of coelurosaurs were recognized, a number of new infraorders were erected, including the Ornithomimosauria, Deinonychosauria, Oviraptorosauria, and Segnosauria (a name which has since been replaced with the unranked clade Therizinosauria). Most modern studies follow phylogenetic nomenclature and refrain from assigning ranks, and those that do use ranks, such as Micheal Benton, have refrained from including the various coelurosaur infraorders in their taxonomies, referring instead to more exclusive individual families.

Traditional 'Coelurosaurs'

Like Carnosauria for large theropods, the Coelurosauria had traditionally been used as a 'dumping ground' for all ''small'' theropods but analysis, in the 1980s and 1990s, revealed that some 'coelurosaurs' were actually more primitive theropods, most notably the coelophysids. Additionally, some dinosaur groups long thought to belong to the Carnosauria, the tyrannosaurids, turned out to be giant coelurosaurs. The large, herbivorous/omnivorous segnosaurs, once thought to be related to either sauropods or ornithischians, have similarly turned out to be coelurosaurs.

Taxonomy

Taxonomy after Benton, 2004. Note that Benton included the oviraptorids as Order Oviraptorosauria within Class Aves.^[3]

★ 'Division Coelurosauria'

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★ Family Coeluridae (including Compsognathidae)

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★ Subdivision Maniraptoriformes

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★ Family Tyrannosauridae

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★ Family Ornithomimidae

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★ Infradivision Maniraptora

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★ Family Alvarezsauridae

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★ Family Therizinosauridae

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★ Cohort Deinonychosauria

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★ Family Dromaeosauridae

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★ Family Troodontidae

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★ Class Aves (including Oviraptorosauria)

Phylogeny

The following cladogram is taken, in abbreviated form, from Weishampel, Dodson, and Osmólska, 2004. They define ''Coelurosauria'' as those dinosaurs sharing a more recent common ancestor with the House Sparrow than with ''Allosaurus fragilis''.^[4]

"Coelurosaurus"

"Coelurosaurus" is an informal generic name, attributed to Friedrich von Huene, 1929 (sometimes incorrectly given as 1914), that is sometimes seen in lists of dinosaurs. It is probably a typographical error; von Huene intended to assign indeterminate remains to Coelurosauria ''incertae sedis'', but at some point in the process of publication, the text was revised to make it appear that he was creating a new generic name "Coelurosaurus" (as described by George Olshevsky in a 1999 post to the Dinosaur Mailing List).^[5] The name is undescribed and has not been used seriously, although it has appeared in works of fiction.

References

1. Feduccia, A. (1993).
2. Mayr, G., B. Pohl & D.S. Peters (2005). "A well-preserved ''Archaeopteryx'' specimen with theropod features". ''Science'', '310'(5753): 1483-1486.
3. Benton, M.J. (2004). ''Vertebrate Palaeontology, Third Edition''. Blackwell Publishing, 472 pp.
4. Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.) (2004). ''The Dinosauria, Second Edition''. University of California Press., 861 pp.
5. Olshevsky, G. Re: What are these dinosaurs. Retrieved on 2007 January 29.

External links

★ Coelurosauria at DinoData.

★ Lark Quarry, Queensland, Australia''. '''Lark Quarry'''.