65-557: Compsognathidae is a family of coelurosaurian theropod dinosaurs . Compsognathids were small carnivores , generally conservative in form, hailing from the Jurassic and Cretaceous Periods . The bird-like features of these species, along with other dinosaurs such as Archaeopteryx inspired the idea for the connection between dinosaur reptiles and modern-day avian species. Compsognathid fossils preserve diverse integument — skin impressions are known from four genera commonly placed in
130-497: A bird-like arrangement of the pectoral bones, where the angled shoulder girdle (coracoids) come in contact with the breastbone (sternum). According to Paul, ornithomimosaurs are the most basal members of this group. In 2010, Paul used Avepectora for a smaller clade, excluding ornithomimosaurs, compsognathids and alvarezsauroids. Within Coelurosauria exists a slightly less inclusive clade named Tyrannoraptora . This clade
195-434: A bird-like arrangement of the pectoral bones, where the angled shoulder girdle (coracoids) come in contact with the breastbone (sternum). According to Paul, ornithomimosaurs are the most basal members of this group. In 2010, Paul used Avepectora for a smaller clade, excluding ornithomimosaurs, compsognathids and alvarezsauroids. Within Coelurosauria exists a slightly less inclusive clade named Tyrannoraptora . This clade
260-467: A common origin with avemetatarsalians . Although rare, complete casts of theropod endocrania are known from fossils. Theropod endocrania can also be reconstructed from preserved braincases without damaging valuable specimens by using a computed tomography scan and 3D reconstruction software. These finds are of evolutionary significance because they help document the emergence of the neurology of modern birds from that of earlier reptiles. An increase in
325-467: A common origin with avemetatarsalians . Although rare, complete casts of theropod endocrania are known from fossils. Theropod endocrania can also be reconstructed from preserved braincases without damaging valuable specimens by using a computed tomography scan and 3D reconstruction software. These finds are of evolutionary significance because they help document the emergence of the neurology of modern birds from that of earlier reptiles. An increase in
390-482: A comparison to similar feathered dinosaur Archaeopteryx in order to propose the origin of birds . Huxley noticed that these dinosaurs shared a similar layout to birds and proposed an exploration of the similarities. He is credited as being the first person to do so. This initial comparison sparked the interest into the origin of birds and feathers. In 1882, Othniel Charles Marsh named a new family of dinosaurs for this species Compsognathidae and officially recognized
455-549: A study by paleontologist Thomas Holtz found a close relationship between the Ornithomimosauria and Troodontidae , and named this group Bullatosauria . Holtz rejected this hypothesis in 1999, and most paleontologists now consider troodontids to be much more closely related to either birds or Dromaeosauridae than they are to ornithomimosaurs, causing the Bullatosauria to be abandoned. The name referred to
520-419: A study by paleontologist Thomas Holtz found a close relationship between the Ornithomimosauria and Troodontidae , and named this group Bullatosauria . Holtz rejected this hypothesis in 1999, and most paleontologists now consider troodontids to be much more closely related to either birds or Dromaeosauridae than they are to ornithomimosaurs, causing the Bullatosauria to be abandoned. The name referred to
585-459: Is Huaxiagnathus , which is estimated from its holotype to be around 1.8 m (5 ft 11 in) long, while Sinocalliopteryx measures around 2.4 m (7 ft 10 in) long. Sinosauropteryx is the most similar to Compsognathus , measuring at most 1.07 m (3 ft 6 in) long. The phylogeny of Compsognathidae organizes this family near the development of feathers in dinosaurs. In 1998, evidence of filamentous protofeathers
650-499: Is Neocoelurosauria , erected by Hendrickx, Mateus, Araújo and Choiniere (2019), They define it as "the clade Compsognathidae + Maniraptoriformes", which can be more or less inclusive than Maniraptoromorpha depending on the topology. The last, and most exclusive of these proposed subclades is Maniraptoriformes . Maniraptoriformes is a clade which may have been united by the presence of pennaceous feathers and wings. This clade contains ornithomimosaurs and maniraptorans . The group
715-499: Is Neocoelurosauria , erected by Hendrickx, Mateus, Araújo and Choiniere (2019), They define it as "the clade Compsognathidae + Maniraptoriformes", which can be more or less inclusive than Maniraptoromorpha depending on the topology. The last, and most exclusive of these proposed subclades is Maniraptoriformes . Maniraptoriformes is a clade which may have been united by the presence of pennaceous feathers and wings. This clade contains ornithomimosaurs and maniraptorans . The group
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#1732779971134780-415: Is due to the fact that Juravenator could also be classified into a similar group within Coelurosauria, Maniraptoriformes . Maniraptoriforms share many similarities with compsognathids and due to the fact that there has been only one verified specimen of Juravenator, experts have disagreed on exactly where to place this genus. Since 2013, Juravenator is still commonly classified as a coelurosaur, but near
845-1024: Is not a monophyletic group as currently defined, and that at least some "compsognathids" represent the juveniles of other tetanurans, including carnosaurs and tyrannosaurs. Here is a simplified version of Cau (2024), which does recover Compsognathidae as a polyphyletic group. Putative compsognathid specimens are in bold. Siamraptor Siamotyrannus Streptospondylus Xuanhanosaurus Poekilopleuron Piveteausaurus Piatnitzkysaurus Marshosaurus Leshansaurus Eustreptospondylus Condorraptor Asfaltovenator Sciurumimus Nedcolbertia Magnosaurus Duriavenator Afrovenator Compsognathus longipes Compsognathus corallestris Torvosaurus tanneri Torvosaurus gurneyi Megalosaurus Scipionyx Wiehenvenator Iberospinus Baryonychinae Coelurosauria Coelurosauria ( / s ɪ ˌ lj ʊər ə ˈ s ɔːr i . ə / ; from Greek , meaning "hollow-tailed lizards")
910-404: Is still not definite. Samples of Juravenator skin show scales instead of feathers, leading into debates about Juravenator ’s place within the family Compsognathidae. However, a 2010 examination of Juravenator under UV light showed filaments similar to those seen on other compsognathid specimens, indicating that it is likely that these dinosaurs had some sort of feathering. A 2020 study concluded
975-659: Is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs . Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids , tyrannosaurs , ornithomimosaurs , and maniraptorans ; Maniraptora includes birds , the only known dinosaur group alive today. Most feathered dinosaurs discovered so far have been coelurosaurs. Philip J. Currie had considered it likely and probable that all coelurosaurs were feathered. However, several skin impressions found for some members of this group show pebbly, scaly skin, indicating that feathers did not completely replace scales in all taxa. In
1040-659: Is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs . Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids , tyrannosaurs , ornithomimosaurs , and maniraptorans ; Maniraptora includes birds , the only known dinosaur group alive today. Most feathered dinosaurs discovered so far have been coelurosaurs. Philip J. Currie had considered it likely and probable that all coelurosaurs were feathered. However, several skin impressions found for some members of this group show pebbly, scaly skin, indicating that feathers did not completely replace scales in all taxa. In
1105-429: 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. In 2018, two anurognathid specimens were found to have integumentary structures similar to protofeathers. Based on phylogenetic analysis, protofeathers would have had
1170-429: 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. In 2018, two anurognathid specimens were found to have integumentary structures similar to protofeathers. Based on phylogenetic analysis, protofeathers would have had
1235-604: Is usually determined through examination of the metacarpal , which is used to separate Compsognathidae from other dinosaurs. However, classification is still complicated due to similarities to the body of several other theropod dinosaurs, as well as the lack of unifying, diagnostic features that are shared by all compsognathids. Some authors have proposed that Compsognathidae is not a monophyletic group, and at least some compsognathids represent juvenile specimens of larger tetanuran theropods, such as carnosaurs and tyrannosaurs. The first significant fossil specimen of Compsognathidae
1300-728: The Morrison Formation in Wyoming at about 150 Ma. Epidendrosaurus and Pedopenna are known from the Daohugou Beds in China at about 165-163 Ma. The wide range of fossils in the late Jurassic and morphological evidence shows that coelurosaurian differentiation was virtually complete before the end of the Jurassic. In the early Cretaceous , a superb range of coelurosaurian fossils (including avians) are known from
1365-435: The Morrison Formation in Wyoming at about 150 Ma. Epidendrosaurus and Pedopenna are known from the Daohugou Beds in China at about 165-163 Ma. The wide range of fossils in the late Jurassic and morphological evidence shows that coelurosaurian differentiation was virtually complete before the end of the Jurassic. In the early Cretaceous , a superb range of coelurosaurian fossils (including avians) are known from
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#17327799711341430-728: The Yixian Formation in Liaoning. All known theropod dinosaurs from the Yixian Formation are coelurosaurs. Many of the coelurosaurian lineages survived to the end of the Cretaceous period (about 66 Ma) and fossils of some lineages, such as the Tyrannosauroidea , are best known from the late Cretaceous. A majority of coelurosaur groups became extinct in the Cretaceous–Paleogene extinction event , including
1495-419: The Yixian Formation in Liaoning. All known theropod dinosaurs from the Yixian Formation are coelurosaurs. Many of the coelurosaurian lineages survived to the end of the Cretaceous period (about 66 Ma) and fossils of some lineages, such as the Tyrannosauroidea , are best known from the late Cretaceous. A majority of coelurosaur groups became extinct in the Cretaceous–Paleogene extinction event , including
1560-465: The proceratosaurid tyrannosauroids Proceratosaurus and Kileskus from the late Middle Jurassic. Many nearly complete fossil coelurosaurians are known from the Late Jurassic . Archaeopteryx (incl. Wellnhoferia ) is known from Bavaria at 155-150 Ma. Ornitholestes , the troodontid Hesperornithoides , Coelurus fragilis and Tanycolagreus topwilsoni are all known from
1625-403: The proceratosaurid tyrannosauroids Proceratosaurus and Kileskus from the late Middle Jurassic. Many nearly complete fossil coelurosaurians are known from the Late Jurassic . Archaeopteryx (incl. Wellnhoferia ) is known from Bavaria at 155-150 Ma. Ornitholestes , the troodontid Hesperornithoides , Coelurus fragilis and Tanycolagreus topwilsoni are all known from
1690-469: The tyrannosaurids , were actually more advanced than allosaurs and therefore were reclassified as giant coelurosaurs. Even more drastically, the segnosaurs , once not even regarded as theropods, have turned out to be non-carnivorous coelurosaurs related to Therizinosaurus . Senter (2007) listed 59 different published phylogenies since 1984. Those since 2005 have followed almost the same pattern, and differ significantly from many older phylogenies. In 1994,
1755-469: The tyrannosaurids , were actually more advanced than allosaurs and therefore were reclassified as giant coelurosaurs. Even more drastically, the segnosaurs , once not even regarded as theropods, have turned out to be non-carnivorous coelurosaurs related to Therizinosaurus . Senter (2007) listed 59 different published phylogenies since 1984. Those since 2005 have followed almost the same pattern, and differ significantly from many older phylogenies. In 1994,
1820-430: The "scales" were actually adipocere , though the same study defended Juravenator was a megalosauroid and not a compsognathid. Another way of classification of Compsognathidae is shared metacarpal morphology . A 2007 study found similarities between compsognathid genera in certain metacarpal I morphologies. The conclusion of this study found that Composgnathidae had a distinct manual morphology where, like theropods,
1885-505: The 1960s several distinctive lineages of coelurosaurs were recognized, and a number of new infraorders were erected, including the Ornithomimosauria , Deinonychosauria , and Oviraptorosauria . During the 1980s and 1990s, paleontologists began to give Coelurosauria a formal definition, usually as all animals closer to birds than to Allosaurus , or equivalent specifiers. Under this modern definition, many small theropods are not classified as coelurosaurs at all and some large theropods, such as
1950-505: The 1960s several distinctive lineages of coelurosaurs were recognized, and a number of new infraorders were erected, including the Ornithomimosauria , Deinonychosauria , and Oviraptorosauria . During the 1980s and 1990s, paleontologists began to give Coelurosauria a formal definition, usually as all animals closer to birds than to Allosaurus , or equivalent specifiers. Under this modern definition, many small theropods are not classified as coelurosaurs at all and some large theropods, such as
2015-450: The 2010s. † Zuolong [REDACTED] † Tyrannosauroidea [REDACTED] † Scipionyx [REDACTED] † Ornithomimosauria [REDACTED] Maniraptora [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] Maniraptoriformes Coelurosauria ( / s ɪ ˌ lj ʊər ə ˈ s ɔːr i . ə / ; from Greek , meaning "hollow-tailed lizards")
Compsognathidae - Misplaced Pages Continue
2080-495: The Cretaceous marine sediments at Mangahouanga Stream. Possible coprolites have been referred to this specimen, however it is still not an officially classified species. Compsognathids share a variety of characteristics. The genera in this family demonstrate traits that are characteristic of theropods , such as smaller forelimbs than hind legs. Size, feathers, and metacarpal size are among the most important classifying common characteristics. Compsognathids are considered to be among
2145-498: The German specimen as a juvenile. This specimen also contained a lizard in the digestive region, further solidifying the theory that compsognathids consumed small vertebrate species. The holotype of Juravenator is the only known specimen of the species. Though Juravenator has previously been accepted as a member of Compsognathidae, recent research has led some experts to believe that Juravenator does not belong in this group. This
2210-569: The Tyrannosauroidea, Ornithomimosauria , Oviraptorosauria , Deinonychosauria , Enantiornithes , and Hesperornithes . Only the Neornithes , otherwise known as modern birds, survived, and continued to diversify after the extinction of the other dinosaurs into the numerous forms found today. There is consensus among paleontologists that birds are descended from coelurosaurs. Under modern cladistical definitions, birds are considered
2275-444: The Tyrannosauroidea, Ornithomimosauria , Oviraptorosauria , Deinonychosauria , Enantiornithes , and Hesperornithes . Only the Neornithes , otherwise known as modern birds, survived, and continued to diversify after the extinction of the other dinosaurs into the numerous forms found today. There is consensus among paleontologists that birds are descended from coelurosaurs. Under modern cladistical definitions, birds are considered
2340-873: The compsognathids to be an example of convergent evolution . The position of Compsognathidae within the coelurosaur group is uncertain. Some, such as theropod expert Thomas Holtz Jr. and co-authors Ralph Molnar and Phil Currie in the landmark 2004 text Dinosauria , hold the family as the most basal of the coelurosaurs, while others as part of the Maniraptora . Below is a simplified cladogram showing Compsognathidae by Senter et al. in 2012. Tyrannosauroidea [REDACTED] Sinocalliopteryx [REDACTED] Huaxiagnathus [REDACTED] Sinosauropteryx [REDACTED] Compsognathus [REDACTED] Juravenator [REDACTED] Scipionyx [REDACTED] Maniraptoriformes [REDACTED] A number of authors have suggested that Compsognathidae
2405-701: The display feathers of a standardwing bird-of-paradise , and unlike any other non-avian dinosaur currently described. The first member of the group, Compsognathus , was discovered in 1861, after Johann A. Wagner published his description of the taxon. The family was created by Edward Drinker Cope in 1875. This classification was accepted by Othniel Charles Marsh in 1882, and added to the Coelurosauria clade by Friedrich von Huene in 1914 after additional fossils had been found. With further discoveries, fossils have been uncovered across three different continents, in Asia, Europe, and South America. Assignment to Compsognathidae
2470-572: The feet, though some primitive coelurosaurian species are known to have had scales on the upper legs and portions of the tail as well. These include tyrannosauroids , Juravenator , and Scansoriopteryx . Fossils of at least some of these animals ( Scansoriopteryx and possibly Juravenator ) also preserve feathers elsewhere on the body. 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
2535-572: The feet, though some primitive coelurosaurian species are known to have had scales on the upper legs and portions of the tail as well. These include tyrannosauroids , Juravenator , and Scansoriopteryx . Fossils of at least some of these animals ( Scansoriopteryx and possibly Juravenator ) also preserve feathers elsewhere on the body. 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
2600-410: The first digit of the manus is larger than the other digits, but with a distinct metacarpal I morphology where the metacarpal is stocky and short. Compsognathidae also has a projection from the manus that is on this metacarpal. The Compsognathidae are a group of mostly small dinosaurs from the late Jurassic and early Cretaceous periods of China, Europe and South America. For many years, Compsognathus
2665-412: The group Maniraptoriformes instead of Compsognathidae. A compsognathid specimen consisting of a single finger bone has been described from Late Jurassic ( Tithonian Age, about 150 million years ago) sediments at Port Waikato, New Zealand. It is the first and so far, only dinosaur specimen known from Jurassic New Zealand, as well as being the first New Zealand dinosaur fossil to have been found outside of
Compsognathidae - Misplaced Pages Continue
2730-442: The group, Compsognathus , Sinosauropteryx , Sinocalliopteryx , and Juravenator . While the latter three show evidence of a covering of some of the earliest primitive feathers over much of the body, Juravenator and Compsognathus also show evidence of scales on the tail or hind legs. " Ubirajara jubatus ", informally described in 2020, had elaborate integumentary structures on its back and shoulders superficially similar to
2795-426: The inflated (bulbous) sphenoid both groups shared. Holtz defined the group as the clade containing the most recent common ancestor of Troodon and Ornithomimus and all its descendants. The concept is now considered redundant, and the clade Bullatosauria is now viewed as synonymous with Maniraptoriformes. In 2002, Gregory S. Paul named an apomorphy-based clade Avepectora , defined to include all theropods with
2860-426: The inflated (bulbous) sphenoid both groups shared. Holtz defined the group as the clade containing the most recent common ancestor of Troodon and Ornithomimus and all its descendants. The concept is now considered redundant, and the clade Bullatosauria is now viewed as synonymous with Maniraptoriformes. In 2002, Gregory S. Paul named an apomorphy-based clade Avepectora , defined to include all theropods with
2925-490: The largest ( Tyrannosaurus ) and smallest ( Microraptor , Parvicursor ) carnivorous dinosaurs ever discovered. Characteristics that distinguish coelurosaurs include: Fossil evidence shows that the skin of even the most primitive coelurosaurs was covered primarily in feathers . Fossil traces of feathers, though rare, have been found in members of most major coelurosaurian lineages. Most coelurosaurs also retained scales and scutes on some portion of their bodies, particularly
2990-490: The largest ( Tyrannosaurus ) and smallest ( Microraptor , Parvicursor ) carnivorous dinosaurs ever discovered. Characteristics that distinguish coelurosaurs include: Fossil evidence shows that the skin of even the most primitive coelurosaurs was covered primarily in feathers . Fossil traces of feathers, though rare, have been found in members of most major coelurosaurian lineages. Most coelurosaurs also retained scales and scutes on some portion of their bodies, particularly
3055-427: 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
3120-427: 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
3185-419: The only living lineage of coelurosaurs. Birds are classified by most paleontologists as belonging to the subgroup Maniraptora . A portion of a tail belonging to a juvenile coelurosaur was found in 2015, inside of a piece of amber. The phylogeny and taxonomy of Coelurosauria has been subject to intensive research and revision. For many years, Coelurosauria was a 'dumping ground' for all small theropods. In
3250-419: The only living lineage of coelurosaurs. Birds are classified by most paleontologists as belonging to the subgroup Maniraptora . A portion of a tail belonging to a juvenile coelurosaur was found in 2015, inside of a piece of amber. The phylogeny and taxonomy of Coelurosauria has been subject to intensive research and revision. For many years, Coelurosauria was a 'dumping ground' for all small theropods. In
3315-620: The past, Coelurosauria was used to refer to all small theropods, but this classification has since been amended. 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 ). The group includes some of
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#17327799711343380-620: The past, Coelurosauria was used to refer to all small theropods, but this classification has since been amended. 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 ). The group includes some of
3445-439: The proportion of the brain occupied by the cerebrum seems to have occurred with the advent of the Coelurosauria and "continued throughout the evolution of maniraptorans and early birds." A few fossil traces tentatively associated with the Coelurosauria date as far back as the late Triassic . What has been found between then and the earliest Middle Jurassic is fragmentary. The oldest known unambiguous members of Coelurosauria are
3510-439: The proportion of the brain occupied by the cerebrum seems to have occurred with the advent of the Coelurosauria and "continued throughout the evolution of maniraptorans and early birds." A few fossil traces tentatively associated with the Coelurosauria date as far back as the late Triassic . What has been found between then and the earliest Middle Jurassic is fragmentary. The oldest known unambiguous members of Coelurosauria are
3575-691: The smallest dinosaurs ever discovered. Compsognathus longipes was formerly the smallest known dinosaur. It was around the size of a chicken when fully grown: around 1 m (3 ft 3 in) long and weighing 2.5 kg (5.5 lb). However, recently discovered adult specimens of other dinosaurs are smaller than Compsognathus , including Caenagnathasia , Microraptor , and Parvicursor , all of which are estimated to be less than 1 m long. However, most of these specimens are incomplete, so these sizes remain estimates. The other genera in this family are slightly larger than Compsognathus longipes , but generally similar in size. The largest compsognathid
3640-402: The species as part of Dinosauria . In 1971, a second nearly complete specimen of Composgnathus longipes was found in the area of Canjuers, which is located in the southeast of France near Nice. This specimen was much larger than the original German specimen, but similarities led to experts categorizing the fossil as an adult Compsognathus longipes and leading to the further classification of
3705-430: 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." Another proposed clade
3770-430: 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." Another proposed clade
3835-423: Was defined by Sereno (1999) as " Tyrannosaurus rex , Passer domesticus (the house sparrow), their last common ancestor , and all of its descendants". 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
3900-423: Was defined by Sereno (1999) as " Tyrannosaurus rex , Passer domesticus (the house sparrow), their last common ancestor , and all of its descendants". 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
3965-549: Was found in the Bavaria region of Germany (BSP AS I 563) and given to collector Joseph Oberndorfer in 1859. The finding was initially significant because of the small size of the specimen. In 1861, after an initial period of review, Johann A. Wagner presented his analysis of the specimen to the public and named the fossil Compsognathus longipes ("elegant jaw"). In 1868, Thomas Henry Huxley , an early supporter of Charles Darwin and his theory of evolution , used Compsognathus in
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#17327799711344030-460: Was named by Thomas Holtz , who defined it as "the most recent common ancestor of Ornithomimus and birds , and all descendants of that common ancestor." One of the possible synapomorphies of this clade is the presence of feathers homologous to those of birds, based on study of a specimen of Shuvuuia . The following family tree illustrates a synthesis of the relationships of the major coelurosaurian groups based on various studies conducted in
4095-460: Was named by Thomas Holtz , who defined it as "the most recent common ancestor of Ornithomimus and birds , and all descendants of that common ancestor." One of the possible synapomorphies of this clade is the presence of feathers homologous to those of birds, based on study of a specimen of Shuvuuia . The following family tree illustrates a synthesis of the relationships of the major coelurosaurian groups based on various studies conducted in
4160-489: Was presented in a study on Sinosauropteryx , marking the first time that any sort of feather structure was found outside of birds and their related species. After this, more evidence of feather structure was found in other genera of Compsognathidae. Evidence of protofeathers bearing resemblance to Sinosauropteryx was found on Sinocalliopteryx specimens, including on the foot of the specimen. There have been signs of basic feather structures on Juravenator , but evidence of this
4225-430: Was the only member known, but in recent decades paleontologists have discovered several related genera. The clade includes Aristosuchus , Huaxiagnathus , Mirischia , Sinosauropteryx , and perhaps Juravenator and Scipionyx . At one time, Mononykus was proposed as a member of the family, but this was rejected by Chen and coauthors in a 1998 paper; they considered the similarities between Mononykus and
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