Theropods Fossil range: Late Triassic - Late Cretaceous (excluding birds)
Tyrannosaurus foot
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Superorder: Dinosauria Order: Saurischia Suborder: Theropoda Marsh, 1881
Infraorders
†Carnosauria †Ceratosauria †Deinonychosauria †Ornithomimosauria †Oviraptorosauria (unranked) Avialae

Theropods (pronounced /ˈθɪərəpɒd/, theropoda /θiːˈrɒpədə/ 'beast feet') are a group of bipedal saurischian dinosaurs. The Late Triassic (also known as Upper Triassic, or Keuper) is the third and final of three epochs of the Triassic period. Late Cretaceous (100mya - 65mya refers to the second half of the Cretaceous Period, named after the famous white Chalk cliffs of southern England Tyrannosaurus ( or, meaning 'tyrant lizard' is a Genus of Theropod Dinosaur. Chordates ( Phylum Chordata) are a group of Animals that includes the Vertebrates together with several closely related Invertebrates Reptiles, or members of the class Reptilia are air-breathing Cold-blooded Vertebrates that have skin covered in scales as opposed to hair or feathers Saurischia (sɔːˈrɪskiə, from the Greek sauros ( σαυρος) meaning 'lizard' and ischion ( ισχιον) meaning 'hip joint' Othniel Charles Marsh ( October 29, 1831 &ndash March 18, 1899) was one of the pre-eminent Paleontologists of the 19th century who This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Carnosauria is a group of large Predatory Dinosaurs that lived during the Jurassic and Cretaceous periods Ceratosaurs are members of a group of Theropod Dinosaurs defined as all theropods sharing a more recent common ancestry with Ceratosaurus than The Deinonychosauria ("fearsome claw lizards" were a successful Clade of theropods in the Late Jurassic and Cretaceous Periods Ornithomimosaurs (meaning ' Bird mimic lizards' or members of the Clade Ornithomimosauria are Theropod Dinosaurs like Oviraptorosaurs ("egg thief lizards" are a group of feathered Maniraptoran Dinosaurs from the Cretaceous Period of what are now Avialae ("bird wings" is a Clade containing Birds ( Aves) and their most immediate Dinosaurian relatives Bipedalism is a form of Terrestrial locomotion where an organism moves by means of its two rear limbs Saurischia (sɔːˈrɪskiə, from the Greek sauros ( σαυρος) meaning 'lizard' and ischion ( ισχιον) meaning 'hip joint' Although they were primarily carnivorous, a number of theropod families evolved herbivory during the Cretaceous Period. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of Theropods first appear during the Carnian age of the Late Triassic about 220 million years ago (MYA) and were the sole large terrestrial carnivores from the Early Jurassic until the close of the Cretaceous, about 65 MYA. The Carnian (less commonly Karnian) is the lowermost stage of the Upper Triassic series (or earliest age of the Late Triassic The Triassic is a geologic period and system that extends from about 251 to 199 Ma (million years ago In Astronomy, Geology, and Paleontology, mya or " mya " is an abbreviation for "million years ago". For general context see Jurassic. The Early Jurassic (in geology referred to as the Lower Jurassic, originally (and still in Europe the The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of Today, they are represented by the 9,300 living species of birds, which evolved in the Late Jurassic from small specialized coelurosaurian dinosaurs. Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. The Late Jurassic (or Malm) Epoch of the Jurassic Period is the unit of geologic time from 161 For the prehistoric gliding reptile see Coelurosauravus. Coelurosauria (sɨˌljʊərəˈsɔriə is defined as the clade containing all Theropod

Among the features linking theropods to birds are the three-toed foot, a furcula (wishbone), air-filled bones and (in some cases) feathers and brooding of the eggs. The furcula (" little fork " in Latin is a forked Bone found in Birds and Theropod Dinosaurs formed by the fusion of the two Incubation is the process by which Birds hatch their eggs, and to the development of the Embryo within the egg In most Birds and Reptiles an egg ( Latin ovum) is the Zygote, resulting from Fertilization of the Ovum.

Evolutionary history

During the late Triassic, a number of primitive proto-theropod and theropod dinosaurs existed and evolved alongside each other. The Triassic is a geologic period and system that extends from about 251 to 199 Ma (million years ago

The earliest and most primitive of the carnivorous dinosaurs were Eoraptor of Argentina and the herrerasaurs. Eoraptor was one of the world's earliest Dinosaurs It was a two-legged meat-eater that lived between 230 and 225  Million years ago For a topic outline on this subject see List of basic Argentina topics. Herrerasaurs are among the oldest known Dinosaurs appearing in the Fossil record about 228 million years ago (mid- Triassic) The herrerasaurs existed from the early late Triassic (Late Carnian to Early Norian). The Carnian (less commonly Karnian) is the lowermost stage of the Upper Triassic series (or earliest age of the Late Triassic The Norian Stage was a portion of the Triassic Geological period. They were found in North America and South America and possibly also India and Southern Africa. South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country The herrerasaurs were characterised by a mosaic of primitive and advanced features. Mosaic Evolution is the concept that major evolutionary changes tend to take place in stages not all at once Some paleontologists have in the past considered the herrerasaurians to be members of Theropoda, though they are now thought to be basal saurischians, and may even have evolved prior to the saurischian-ornithischian split. In Phylogenetics, a basal Clade is the earliest clade to branch in a larger clade it appears at the base of a cladogram

Theropod footprint.

The earliest and most primitive unambiguous theropods (or alternatively, Eutheropoda - 'True Theropods') are the Coelophysidae. The Coelophysidae are a family of primitive carnivorous Theropod Dinosaurs Most species were relatively small in size The Coelophysidae (Coelophysis, Megapnosaurus) were a group of widely distributed, lightly built and apparently gregarious animals. The Coelophysidae are a family of primitive carnivorous Theropod Dinosaurs Most species were relatively small in size Coelophysis (siːˈloʊfaɪsɨs see-LOH-fye-siss meaning "hollow form " in reference to its hollow Bones ( Greek κοιλος Megapnosaurus (meaning "big dead lizard" from Greek μεγα = "big" 'απνοος = "not breathing" "dead" σαυρος They included small hunters like Coelophysis and larger (6 meters) predators like Dilophosaurus. Dilophosaurus was a Theropod Dinosaur from the Early Jurassic Period. These successful animals continued from the Late Carnian (early Late Triassic) through to the Toarcian (late Early Jurassic). The Toarcian Stage was the last Faunal stage of the Early Jurassic period For general context see Jurassic. The Early Jurassic (in geology referred to as the Lower Jurassic, originally (and still in Europe the Although in the early cladistic classifications they were included under the Ceratosauria and considered a side-branch of more advanced theropods,^[1] they may have been ancestral to all other theropods (which would make them a paraphyletic group. Cladistics is the hierarchical classification of Species based on evolutionary ancestry Ceratosaurs are members of a group of Theropod Dinosaurs defined as all theropods sharing a more recent common ancestry with Ceratosaurus than In Phylogenetics, a group of organisms is said to be paraphyletic if the group contains its most recent common ancestor but does not contain all ^[2][3]

The somewhat more advanced true Ceratosauria (including Ceratosaurus and Carnotaurus) appeared during the Early Jurassic and continued through to the Late Jurassic in Laurasia. Ceratosaurs are members of a group of Theropod Dinosaurs defined as all theropods sharing a more recent common ancestry with Ceratosaurus than Ceratosaurus (ˌsɛrətəˈsɔrəs meaning 'horned lizard' in reference to the horn on its nose ( Greek κερας/κερατος keras/keratos meaning Carnotaurus (ˌkɑrnoʊˈtɔrəs KAHR-noh-TAWR-us meaning "meat-bull" referring to its distinct bull-like horns ( Latin carne = flesh + Laurasia (lɔˈreɪʃiə lɔˈreɪʒə was a Supercontinent that most recently existed as a part of the split of the Pangaean supercontinent in the late Mesozoic They competed quite well alongside their more advanced tetanuran relatives and - in the form of the abelisaur lineage - lasted to the end of the Cretaceous in Gondwana. Abelisaurs were a group of Ceratosaurian Dinosaurs which lived all over the southern hemisphere (with the exception of Tarascosaurus in Southern Gondwana (ɡɒnˈdwɑːnə originally Gondwanaland) was a southern Supercontinent that existed about 500 to 200 Ma ago

Skeletal reconstructions of several theropod dinosaurs.

The Tetanurae are more specialised again than the Ceratosaurs. Tetanurae, or "stiff tails" is a Clade that includes most theropod dinosaurs including Birds Tetanurans (or tetanurines first appear during the early They are subdivided into Megalosauroidea (alternately Spinosauroidea or Torvosauroidea) and the Avetheropoda. Spinosauroidea is a superfamily of tetanuran theropod Dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period Spinosauroidea is a superfamily of tetanuran theropod Dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period Spinosauroidea is a superfamily of tetanuran theropod Dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period Tetanurae, or "stiff tails" is a Clade that includes most theropod dinosaurs including Birds Tetanurans (or tetanurines first appear during the early They were most common during the Middle Jurassic but continued to the Middle Cretaceous. The latter clade - as their name indicates - were more closely related to birds and are again divided into the Carnosauria (including Allosaurus) and the Coelurosauria, a very large and diverse dinosaur group that was especially common during the Cretaceous. A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor Carnosauria is a group of large Predatory Dinosaurs that lived during the Jurassic and Cretaceous periods Allosaurus (ˌæləˈsɔrəs is a Genus of large Theropod Dinosaur that lived 155 to 145 million years ago in the Late Jurassic For the prehistoric gliding reptile see Coelurosauravus. Coelurosauria (sɨˌljʊərəˈsɔriə is defined as the clade containing all Theropod

Thus, during the late Jurassic, there were no fewer than four distinct lineages of theropods - ceratosaurs, megalosaurs, carnosaurs, and coelurosaurs - preying on the abundance of small and large herbivorous dinosaurs. All four groups survived into the Cretaceous, although only two - the abelisaurs and the coelurosaurs - seem to have made it to end of the period, where they were geographically separate, the abelisaurs in Gondwana, and the coelurosaurs in Asiamerica. Asiamerica was a large island formed from the Laurasian landmass and separated by shallow continental seas from Eurasia to the West and eastern North America

Of all the theropod groups, the coelurosaurs were by far the most diverse. Some coelurosaur clades that flourished during the Cretaceous were the tyrannosaurids (including Tyrannosaurus) the dromaeosaurids (including Velociraptor and Deinonychus, which are remarkably similar in form to the oldest known bird, Archaeopteryx^[4][5]), the bird-like troodontids and oviraptorosaurs, the ornithomimosaurs (or "ostrich dinosaurs"), the strange giant-clawed herbivorous Therizinosauridae, and the birds, which are the only dinosaur lineage to survive the end Cretaceous mass-extinction. Tyrannosauridae (or tyrannosaurids, meaning "tyrant lizards" is a family of Coelurosaurian Theropod Dinosaurs which Tyrannosaurus ( or, meaning 'tyrant lizard' is a Genus of Theropod Dinosaur. Dromaeosauridae is a family of Bird -like Theropod Dinosaurs They were small to medium-sized feathered Carnivores that flourished in the Velociraptor (vɨˈlɒsɨræptɚ meaning 'swift thief' 'swift plunderer' or 'swift bird of prey' is a Genus of Dromaeosaurid theropod Deinonychus (daɪˈnɒnikəs ( Greek δεινος, 'terrible' and ονυξ/ονυχος, 'claw' was a Genus of carnivorous Archaeopteryx, sometimes referred to by its German name Urvogel ("original bird" or "first bird" is the earliest and most primitive Bird Troodontidae is a family of Bird -like theropod Dinosaurs In previous decades troodontid fossils were few and scrappy and they have therefore Oviraptorosaurs ("egg thief lizards" are a group of feathered Maniraptoran Dinosaurs from the Cretaceous Period of what are now Ornithomimosaurs (meaning ' Bird mimic lizards' or members of the Clade Ornithomimosauria are Theropod Dinosaurs like Therizinosauridae ("reaper lizards" is a family of advanced herbivorous or omnivorous Theropod Dinosaurs Therizinosaurid Fossil remains Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. ^[6] While the roots of these various groups must have been in the Late or possibly even the Middle Jurassic, they only became abundant during the Early Cretaceous. A few paleontologists, such as Gregory S. Paul, have suggested that some or all of these advanced theropods were actually descended from flying dinosaurs or proto-birds like Archaeopteryx that lost the ability to fly and returned to a terrestrial habitat. Gregory S Paul (born 1954) is a Freelance Paleontologist, Author and Illustrator. ^[7]

Classification

History of classification

The name Theropoda (meaning "beast feet") was first coined by O.C. Marsh in 1881. Othniel Charles Marsh ( October 29, 1831 &ndash March 18, 1899) was one of the pre-eminent Paleontologists of the 19th century who Marsh initially named Theropoda as a suborder to include the family Allosauridae, but later expanded its scope, re-ranking it as an order to include a wide array of "carnivorous" dinosaur families, including Megalosauridae, Compsognathidae, Ornithomimidae, Plateosauridae and Anchisauridae (now known to be herbivorous prosauropods) and Hallopodidae (now known to be relatives of crocodilians). This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used In Biological classification, family ( Latin Allosauridae was a family of medium to large sized carnivorous Theropod Dinosaurs They lived during the Late Jurassic and Early Cretaceous This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Megalosauridae was a family of relatively primitive tetanuran theropod dinosaurs order Saurischia. Compsognathidae is a family of small carnivorous Dinosaurs generally conservative in form from the Jurassic and Cretaceous Periods Ornithomimosaurs (meaning ' Bird mimic lizards' or members of the Clade Ornithomimosauria are Theropod Dinosaurs like Plateosauridae is a family of the Infraorder Prosauropoda of the Suborder Sauropodomorpha. The Anchisauridae were a group of early Sauropodomorph Dinosaurs first proposed by Othniel Charles Marsh in 1885 Prosauropoda (ˌproʊsɔˈrɒpədə or prosauropods (/proʊˈsɔroʊpɒd/ were a group of early Herbivorous Dinosaurs that lived during the Triassic Hallopus was a prehistoric Reptile, classified by O C Marsh in 1881 as a Dinosaur. Due to the scope of Marsh's Order Theropoda, it came to replace a previous taxonomic group that Marsh's rival E.D. Cope had created in 1866 for the carnivorous dinosaurs, Goniopoda ("angled feet"). Edward Drinker Cope (July 28 1840&ndashApril 12 1897 was an American paleontologist and comparative anatomist, as well as a noted herpetologist ^[8]

By the early 20th Century, some paleontologists, such as Friedrich von Huene, no longer considered carnivorous dinosaurs to have formed a natural group. Friedrich von Huene ( March 22, 1875 &ndash April 4, 1969) was a German Paleontologist who named more Dinosaurs Huene abandoned the name Theropoda, instead using Harry Seeley's Order Saurischia, which Huene divided into the suborders Coelurosauria and Pachypodosauria. Harry Govier Seeley ( 18 February 1839 - 8 January 1909) was a British Paleontologist who determined that Dinosaurs Saurischia (sɔːˈrɪskiə, from the Greek sauros ( σαυρος) meaning 'lizard' and ischion ( ισχιον) meaning 'hip joint' For the prehistoric gliding reptile see Coelurosauravus. Coelurosauria (sɨˌljʊərəˈsɔriə is defined as the clade containing all Theropod Huene placed most of the small theropod groups into Coelurosauria, and the large theropods and prosauropods into Pachypodosauria, which he considered ancestral to the Sauropoda (prosauropods were still thought of as carnivorous at this time, owing to the incorrect association of rauisuchian skulls and teeth with prosauropod bodies, in animals such as Teratosaurus). Sauropoda (sɔˈrɒpədə or the sauropods (/ˈsɔroʊpɒd/ are a suborder or infraorder of the Saurischian ("lizard-hipped" Rauisuchia are a poorly known assemblage of predatory and mostly large (often 4 to 6 meters Triassic Archosaurs Originally it was believed that they were related Teratosaurus (Gr teras "monster" + sauros "lizard" was a Genus of Rauisuchian known from the Triassic ^[8] In W. D. Matthew and Barnum Brown's 1922 description of the first known dromaeosaurid (Dromaeosaurus albertensis^[9]), they became the first paleontologists to exclude prosauropods from the carnivorous dinosaurs, and attempted to revive the name Goniopoda for that group, though neither of these suggestions were accepted by other scientists. Barnum Brown ( February 12, 1873 - 1963) born February 12 1873 in Carbondale Kansas. Dromaeosauridae is a family of Bird -like Theropod Dinosaurs They were small to medium-sized feathered Carnivores that flourished in the Dromaeosaurus (ˌdrɒmioʊˈsɔrəs was a Genus of Theropod Dinosaur which lived during the Late Cretaceous period ( Campanian ^[8]

It was not until 1956 that Theropoda came back into use as a taxon containing the carnivorous dinosaurs and their descendants, when Alfred Romer re-classified the Order Saurischia into two suborders, Theropoda and Sauropoda. A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to Alfred Sherwood Romer ( December 28, 1894 - November 5, 1973) was an American Paleontologist and comparative Anatomist and Sauropoda (sɔˈrɒpədə or the sauropods (/ˈsɔroʊpɒd/ are a suborder or infraorder of the Saurischian ("lizard-hipped" This basic division has survived into modern paleontology, with the exception of, again, the Prosauropoda, which Romer included as an infraorder of theropods. This article is about the taxonomic rank for the sequence of species in a taxonomic list see Taxonomic order In scientific classification used Romer also maintained a division between Coelurosauria and Carnosauria (which he also ranked as infraorders). Carnosauria is a group of large Predatory Dinosaurs that lived during the Jurassic and Cretaceous periods This dichotomy was upset by the discovery of Deinonychus and Deinocheirus in 1969, neither of which could be classified easily as "carnosaurs" or "coelurosaurs. Deinonychus (daɪˈnɒnikəs ( Greek δεινος, 'terrible' and ονυξ/ονυχος, 'claw' was a Genus of carnivorous Deinocheirus (ˌdaɪnəˈkaɪrəs DYE-no-KYE-rus Greek: 'terrible hand' was a Theropod Dinosaur which lived in what is now southern Mongolia " In light of these and other discoveries, by the late 1970s Rinchen Barsbold created a new series of theropod infraorders: Coelurosauria, Deinonychosauria, Oviraptorosauria, Carnosauria, Ornithomimosauria, and Deinocheirosauria. Dr Rinchen Barsbold (Ринченгийн Барсболд, Rinchyengiin Barsbold) is a Mongolian paleontologist and geologist. The Deinonychosauria ("fearsome claw lizards" were a successful Clade of theropods in the Late Jurassic and Cretaceous Periods Oviraptorosaurs ("egg thief lizards" are a group of feathered Maniraptoran Dinosaurs from the Cretaceous Period of what are now Ornithomimosaurs (meaning ' Bird mimic lizards' or members of the Clade Ornithomimosauria are Theropod Dinosaurs like Deinocheirus (ˌdaɪnəˈkaɪrəs DYE-no-KYE-rus Greek: 'terrible hand' was a Theropod Dinosaur which lived in what is now southern Mongolia ^[8]

With the advent of cladistics and phylogenetic nomenclature in the 1980s, and their development in the 1990s and 2000s, a clearer picture of theropod relationships began to emerge. Cladistics is the hierarchical classification of Species based on evolutionary ancestry Phylogenetic nomenclature (PN is an alternative to rank-based nomenclature. Several major theropod groups were named by Jacques Gauthier in 1986, including the clade Tetanurae for one branch of a basic theropod split with another group, the Ceratosauria. Jacques Armand Gauthier is a vertebrate paleontologist, comparative morphologist, and systematist and one of the founders of the use of Cladistics in biology A clade is a taxonomic group comprising a single Common ancestor and all the descendants of that ancestor Tetanurae, or "stiff tails" is a Clade that includes most theropod dinosaurs including Birds Tetanurans (or tetanurines first appear during the early Ceratosaurs are members of a group of Theropod Dinosaurs defined as all theropods sharing a more recent common ancestry with Ceratosaurus than As more information about the link between dinosaurs and birds came to light, the more bird-like theropods were grouped in the clade Maniraptora (also named by Gauthier in 1986). Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Maniraptora ("hand snatchers" is a Clade of Coelurosaurian Dinosaurs which includes the Birds and the dinosaurs that were more closely These new developments also came with a recognition among most scientists that birds arose directly from maniraptoran theropods and, with the abandonment of ranks in cladistic classification, the re-evaluation of birds as a subset of theropod dinosaurs that happened to have survived the Mesozoic extinctions into the present. ^[8]

Taxonomy

• Suborder Theropoda
  • Agnosphitys
  • Chindesaurus
  • Guaibasaurus
  • Infraorder Ceratosauria
    • Family Ceratosauridae
    • Superfamily Abelisauroidea
    • Superfamily Coelophysoidea
  • Clade Tetanurae
    • Superfamily Spinosauroidea
    • Infraorder Carnosauria
      • Superfamily Allosauroidea
    • Clade Coelurosauria
      • Family Coeluridae
      • Family Compsognathidae
      • Superfamily Tyrannosauroidea
      • Infraorder Ornithomimosauria
      • Clade Maniraptora
        • Family Scansoriopterygidae
        • Superfamily Therizinosauroidea
        • Infraorder Deinonychosauria
          • Family Dromaeosauridae
          • Family Troodontidae
        • Infraorder Oviraptorosauria

Phylogeny

The following cladogram is adapted from Weishampel et al. Agnosphitys (ˌægnoʊsˈfaɪtɪs sometimes mistakenly called Agnostiphys or Agnosphytis) is a disputed Genus of Dinosaur Chindesaurus (ˌtʃɪndɨˈsɔrəs CHIN-dee-SAWR-us - Chinde ( Navajo, Chiindii) meaning "ghost or evil spirit" and Greek Guaibasaurus (meaning "Guaiba lizard" was a basal Saurischian Dinosaur Genus which lived during the Triassic period Ceratosaurs are members of a group of Theropod Dinosaurs defined as all theropods sharing a more recent common ancestry with Ceratosaurus than Ceratosauridae is a Family of Theropod Dinosaurs belonging to the Infraorder Ceratosauria. Abelisaurs were a group of Ceratosaurian Dinosaurs which lived all over the southern hemisphere (with the exception of Tarascosaurus in Southern Coelophysoids were common Dinosaurs of the Late Triassic and Early Jurassic periods Tetanurae, or "stiff tails" is a Clade that includes most theropod dinosaurs including Birds Tetanurans (or tetanurines first appear during the early Spinosauroidea is a superfamily of tetanuran theropod Dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period Carnosauria is a group of large Predatory Dinosaurs that lived during the Jurassic and Cretaceous periods Allosauroidea is a superfamily or Clade of Theropod Dinosaurs which contains three families — the Sinraptoridae, Carcharodontosauridae For the prehistoric gliding reptile see Coelurosauravus. Coelurosauria (sɨˌljʊərəˈsɔriə is defined as the clade containing all Theropod Coeluridae is an historically Paraphyletic (unnaturally grouped family of generally small carnivorous Dinosaurs from the late Jurassic Compsognathidae is a family of small carnivorous Dinosaurs generally conservative in form from the Jurassic and Cretaceous Periods Tyrannosauroidea (meaning 'tyrant lizard forms' is a Superfamily (or Clade) of Coelurosaurian Theropod Dinosaurs that includes Ornithomimosaurs (meaning ' Bird mimic lizards' or members of the Clade Ornithomimosauria are Theropod Dinosaurs like Maniraptora ("hand snatchers" is a Clade of Coelurosaurian Dinosaurs which includes the Birds and the dinosaurs that were more closely Scansoriopterygidae (meaning "climbing wings" may be a family of maniraptoran Dinosaurs known from well-preserved Fossils uncovered in Liaoning Therizinosaurs (or segnosaurs) were theropod Dinosaurs and members of the Clade Therizinosauroidea The Deinonychosauria ("fearsome claw lizards" were a successful Clade of theropods in the Late Jurassic and Cretaceous Periods Dromaeosauridae is a family of Bird -like Theropod Dinosaurs They were small to medium-sized feathered Carnivores that flourished in the Troodontidae is a family of Bird -like theropod Dinosaurs In previous decades troodontid fossils were few and scrappy and they have therefore Oviraptorosaurs ("egg thief lizards" are a group of feathered Maniraptoran Dinosaurs from the Cretaceous Period of what are now Cladistics is the hierarchical classification of Species based on evolutionary ancestry , 2004. ^[10]

Size

Size comparison of selected giant theropod dinosaurs. Therizinosaurs (or segnosaurs) were theropod Dinosaurs and members of the Clade Therizinosauroidea Paraves is a stem–based Clade containing Birds (clade Aves and other closely related Dinosaurs The paravians include the Avialae, such Paraves is a stem–based Clade containing Birds (clade Aves and other closely related Dinosaurs The paravians include the Avialae, such The Deinonychosauria ("fearsome claw lizards" were a successful Clade of theropods in the Late Jurassic and Cretaceous Periods Avialae ("bird wings" is a Clade containing Birds ( Aves) and their most immediate Dinosaurian relatives

Tyrannosaurus was the largest and most popular theropod known to the general public for many decades. Tyrannosaurus ( or, meaning 'tyrant lizard' is a Genus of Theropod Dinosaur. Since its discovery, however, a number of other giant carnivorous dinosaurs have been described, including Spinosaurus, Carcharodontosaurus, Giganotosaurus, Tyrannotitan and Mapusaurus. Spinosaurus (meaning "spine lizard" is a Genus of theropod Dinosaur which lived in what is now North Africa, from Carcharodontosaurus (ˌkɑrkərəˌdɒntəˈsɔːrəs was a gigantic carnivorous carcharodontosaurid Dinosaur that lived around 98 to 93 Giganotosaurus (meaning 'giant southern lizard' derived from the Ancient Greek gigas/γίγας meaning 'giant' notos/νότος Tyrannotitan is a Genus of huge (up to around 122  Metres (40  ft) long Bipedal carnivorous Dinosaur Mapusaurus ('earth lizard' was a giant Carnosaurian Dinosaur from the Late Cretaceous of what is now Argentina. The original Spinosaurus specimens (as well as newer fossils described in 2006) support the idea that Spinosaurus is larger than Tyrannosaurus, showing that Spinosaurus was possibly 6 meters longer and at least 1 metric ton heavier than Tyrannosaurus. There is still no clear scientific explanation for exactly why these animals grew so much larger than the predators that came before and after them. Parallel to this, the smallest known theropod is the bee hummingbird. The Bee Hummingbird ( Mellisuga helenae) is a Hummingbird, and the smallest of all Birds It can be found in Cuba (where it is called the

References