Therizinosaurus was a very tall animal, likely having a reduced competition over the foliage in its habitat and outmatching predators like Tarbosaurus. This helped confirm they belonged to the . Some of the highest stress, deformation, and strain magnitudes were obtained in the scratch/digging scenario, the hook-and-pull scenario, in contrast, resulted in lower magnitudes, and lesser ones were found in the piercing scenario.
Kasey's Creature Features: Therizinosaurus - Tokyo Mew Mew - Fanpop Its upper articulation was divided into three parts.
Therizinosauridae - Wikipedia [24][25] In 1990, Barsbold and Teresa Maryanska agreed in that the hindlimb material from Hermiin Tsav referred to Therizinosaurus in 1982 was segnosaurian since it matched several traits, but considered it unlikely to belong to the genus and species as there was no overlapping material among specimens. One theory is that primitive members were already present in both Asia and North America before it began to drift apart, suggesting an emergence for therizinosaurs of at least the Late Triassic. It had robust and convex crest-like borders. In genera where both neck and forelimb elements are preserved, however, the necks were equal in length or longer than the forelimbs, so pulling vegetation would only be likely if lower parts of long branches were pulled down to access out-of-reach vegetation. The deltopectoral crest (deltoid muscle attachment) was particularly long and thick, with its top located approximately 1/3 from the upper end. Most therizinosaurids had sharply pointed and recurved unguals with very robust tubercles (flexor tendons attachment). This is unusual as nearly all the other Therapods evolved to be carnivores. [40][11], The cladogram below follows the 2019 phylogenetic analysis by Scott Hartman and colleagues, which is largely based on the work from Zanno in 2010. In this comprehensive description, the amount of egg clutches was corrected to at least 15, noting that the eggs were laid in clutches composed of 3 to 30 eggs and hatched in the same single nesting season. Therizinosaurus was 30 feet long from its beak to its tail. If Therizinosaurus was a grazer, on the other hand, it would have competed with contemporary grazers such as Saurolophus. This family of theropod dinosaurs had a very unusual set of characteristics including long necks, small heads, potbellies, feathers, and gangly front limbs with long claws. This extension was supplied by neurovascular foramina (small pits) found on the lateral surfaces. [4][18][8], Therizinosaurus had a rather stocky and robust tibia that was very wide on its lower end. Additionally, most therizinosaurian characters are more notorious in this phase, such as the edentulous premaxilla. [12] The braincases are directed to the bottom, co-ossified with well-developed sideways oriented paroccipital projections, highly pneumatized and had a prominent central foramen. Currently, Therizinosauridae comprises eight described and named taxa. [7][10][12] In Erlikosaurus however, they are massive, combining a stiff and recurved shape with robust tubercles. Explore Therizinosaurus, a large theropod in the Dinosaur Directory.
Therizinosaur | Museum of Northern Arizona It is also possible that a herd of hadrosaurids and therizinosaurids walked across this terrain at different times and did not encounter each another. [8] Another type of dental morphology is the one seen on the highly specialized Segnosaurus. [11][26], In therizinosaurids, the shoulder girdle was robustly specialized than in other maniraptorans and less bird-like. Other traits that were likely present in Therizinosaurus include a heavily pneumatized (air-filled) vertebral column and a robustly-built, ophistopubic (backwards oriented) pelvis. The supraglenoid thickness was developed in a convex crest-shaped form, it was divided across the top of the scapulocoracoid suture. Therizinosaurus was a 30ft long dinosaur of the theropod family. Meet the Therizinosaurus family, the dino-universe's version of the Bellelli Family painted by Edgar Degas.
The most primitive therizinosaur, Falcarius, has been described as a transitional species because it has herbivorous dentition and wider hips; however, it also possessed a pubis bone and legs that resembled those of its running, carnivorous ancestors. [6] In 1990, Barsbold and Teresa Maryanska agreed with Perle in that the hindlimb material from Hermiin Tsav he described in 1982 was therizinosaurian (then called segnosaurians) given that the metatarsus was stocky and the astragalus had a laterally arched ascending process (bony extension), but cast doubt with his referral of it to Therizinosaurus and the segnosaurian identity for this taxon since it was only known from the pectoral girdle and other forelimb elements, making direct comparisons between specimens impossible. While every effort has been made to follow citation style rules, there may be some discrepancies. The fossil remains were discovered in 1918 during Mongolian field expedition on the Nemegt Formation of the Gobi Desert. Ph.D. As its arms were long enough to have touched the ground during certain stances, they could have helped the dinosaur to rise from a prone position. The lateral projection of the astragalus is thickened and extends to the midline of the whole element from the inner side to the rear, leading space for the lower end of the tibia; this exposes the lateral surface of the tibia in a frontal view. Lautenschlager noted the more strongly curved and elongate claws of some therizinosaurian taxa were poorly functional in a scratch/digging fashion, indicating this as the most unlikely function. Based on microscopical features in the eggshells, they identified the eggs as dendroolithids, which had previously been attributed to therizinosaur-grade dinosaurs. [36] A 2023 study by Qin, Rayfield, Benton et al., regarding the claw function in therizinosaurids and alvarezsaurids, which represent the extremes of theropod claw morphology, suggest that there was no mechanical function identifiable for Therizinosaurus, suggesting the claws on its forelimbs were merely decorative rather than functional and a result of peramorphic growth resulting from increased body size. Based on the developmental states preserved within embryos, Kundrt and colleagues suggested a rough incubation period between 1.5 and 3 months. The long claws were likely used for foraging and defence not hunting. This was however, based on the assumption of a giant marine turtle. [3] In the same year, paleontologist Dong Zhiming described the genus Nanshiungosaurus, but wrongly interpreted the remains to have pertained to some kind of dwarf sauropod. It had a broad upper end. A large foramen was also present on the coracoid. Although theropods, include carnivores like T-Rex and Velociraptor, Therizinosaurus was in fact a herbivore. The attachment for the biceps muscle was prominently developed by a large tubercle with a stocky top, indicating powerful muscles in life. [16] It is also possible that Therizinosaurus competed for other various resources with Deinocheirus, Saurolophus, Nemegtosaurus and Opisthocoelicaudia.[43]. Approximately the 50% of the nesting area has been eroded, and based on the egg clutches distribution, the nest density can be estimated around 1 nest per 10 m2. It is just as powerful and dangerous as the Rex and Spino.Although it is built like a Tyrannosaurus or an Allosaurus, and despite the dossier calling it a predator, the creature is a herbivore, using its scythe-like claws to pull down leafy vegetation for consumption. [3], Further expeditions in the Nemegt Formation unearthed more fossils of Therizinosaurus. [4][18][8], The humerus was robustly built, measuring 76cm (30in) long. [52][53], The idea of a land bridge is even more supported by the multiple co-occurrence of hadrosaurid and therizinosaurid footprints at the lower Cantwell Formation of the Denali National Park, which reflects an important faunal exchange between landmasses. It's huge, nearly 30 feet tall, and weighing five tonnes." - David Attenborough, Forests Therizinosaurus is estimated to have reached up to 10 meters (33 feet . The expeditions unearthed numerous dinosaur and turtle fossil remains from the stratotype locality Nemegt (also known as Nemegt Valley), but the most notable elements collected were three partial manual unguals (claw bones) of considerable size. [37], Scott A. Lee and Zachary Richards in 2018 based on bending resistance measurements of several dinosaur humeri, found the humeri of carnosaur, therizinosaur, and tyrannosaur dinosaurs to be relatively resilient to stress. Regardless of these explanations, the therizinosaurid trackway reflects a gregarious behaviour in these theropods. The condyles were developed onto the anterior side of the lower expansion while the epicondyles were very broad and projected over the limits of the articular areas. The lower heads were nearly symmetrical, but the central depression was considerably wider and deeper in the first phalanx. One of the most notable adaptations in advanced therizinosaurids are the four-toed feet, which had a fully functional, weight-bearing first digit that was likely adapted to slow life-style. Therizinosaurus is an extinct genus of the therizinosaurid family that lived in Mongolia during the Late Cretaceous period around 70 million years ago.The ap. By contrast, the straighter and more elongated dentaries of primitive therizinosaurs had the highest magnitudes of stress and strain. The upper articulation was configured into three parts. As the bite force started to decrease from primitive to derived therizinosaurians, Therizinosaurus, being a derived member, would have been subject to the evolutionary relationship. Unlike most other theropods groups, the first pedal digit wasthough shorter than the othersfunctional and weight-bearing. Maleev considered that the claws belonged to a giant marine turtle and named the new genus and species Therizinosaurus cheloniformis, also erecting the Therizinosauridae to include the new species. [48][49], In 1964, Zakharov described and named the particular ichnogenus Macropodosaurus, which is represented by a series of four-toed footprints. [1], In the 1970s more findings were made including the naming of more taxa. [45], Among therizinosaurids, the forelimbs were increased in robustness and the flexibility of the wrist was increased as well, with this, the presumed reach for foraging is likely to have lengthened. "An adult Therizinosaurus. Therizinosaur is Greek for "reaping lizard". Although the extension of the beak on the dorsal surface of the snout is unknown, it is estimated that it slightly overlapped the nasal cavity as in some modern-day birds. [64], The prominent nesting site of the Javkhlant Formation indicates that colonial nesting first evolved in non-avian dinosaur species to increase hatching success in ecosystems subject to high nest predation pressure (such as this formation). Therizinosaurus A.K.A. The unique and bizarre features of the group has encouraged research into the paleobiology and paleoecology of the family. [4][18][8], The first lower carpal bone measured 8.23cm (3.24in) tall and 8.53cm (3.36in) wide and had two articulation surfaces on its lowermost end. It had a wide body and a low center of gravity. He analyzed the pelvis of the new genus and pointed out that segnosaurids were so different from other theropods that they could be outside the group or represent a different lineage of theropod dinosaurs. Possibly the most remarkable theroy about this creature is the large arms with sharp, long claws on each of its hands. [12], Therizinosaurids were quite advanced and robustly-built animals that reached multi-ton dimensions which make them among the largest maniraptorans. Several four-toed tracks were found in Poland, and a series of footprints dating back to the Late Cretaceous were found in Morocco. Unfortunately, the braincase of Neimongosaurus has not been described nor illustrated. This footprint is reminiscent of the tracks described by Zakharov and therefore assigned to Macropodosaurus sp. Due to some primitive characters present in Alxasaurus they coined a new taxonomic rank, the Therizinosauroidea, containing the new taxon and Therizinosauridae. The oofamily Dendroolithidae is often attributed to therizinosaur-grade dinosaurs. [13][14][15], In 2010, Senter and James used hindlimb length equations to predict the total length of the hindlimbs in Therizinosaurus and Deinocheirus. Its brown, bristle-like feathers are broken up by a shock of blue around its neck and head, and sword-like claws extend from its arms. [60][61] However, in 2007 these were described by paleontologist Martin Kundrt and colleagues and tentatively identified as therizinosaurids based on anatomical features such as the tooth-less premaxilla with a downturned edge, dentary with a lateral shelf, teeth with leaf-shaped crowns, humerus with a prominent deltopectoral crest, ilium with an expanded anterior end, and the elongated, sharply-pointed manual unguals. In 1984, Gregory S. Paul claimed that segnosaurs, rather than being theropods, were indeed sauropodomorphs that successfully managed to remain in the Cretaceous period. This dinosaur, like most theropods, had three claws on each arm.
Pictures and Profiles of Therizinosaur Dinosaurs - ThoughtCo [2] Barsbold in 1976 suggested that the unusual claws of Therizinosaurus may have been employed to impale or dig up loose terrain, however, he pointed out their notorious fragility upon impact. The diversity of the ichnotaxa in this site supports the idea of similar dinosaur faunas between Alaska and Asia during the Late Cretaceous period, specifically with the Nemegt Formation which had relatively wet environments. When Therizinosaurus was found, it was first thought to . [7] However, based on osteological features, in 1984 Gregory S. Paul proposed that segnosaurs were no theropods but Late Cretaceous prosauropods and they represented a transitional form between prosauropods and ornithischians. Like other therizinosaurids, it would have been a slow-moving, long-necked, high browser equipped with a rhamphotheca (horny beak) and a wide torso for food processing. However, he could neither confirm nor disregard that the hand claws could have been fully used for sexual display, self-defense, intraspecific competition, mate-gripping during mating or grasping stabilization when foraging. Since Laurasia was beginning to break apart during the Cretaceous, two theories have arisen to explain how therizinosaurs could have spanned across Laurasia. The independence from their parents may also be supported by the development of the teeth of the hatchlings that is consistent to an omnivorous diet. This last proposal is supported by the presence of therizinosaurids in North America during the early Late Cretaceous such as Nothronychus. Based on the smooth outer surface, both inner and outer portions, and several irregular-shaped pore canals of these eggs, they were corroborated to pertain to the Dendroolithidae. He noted that this new family was different from Therizinosauridae based on claw and antebrachium traits. [14] The exponential sizes obtained across the Therizinosauridae appear to have been triggered by the bulk and specialized diet within the group and early members of the Therizinosauria. [44][42][45][46] Additional paleofauna includes birds like Judinornis or Teviornis; abundant freshwater ostracods at numerous localities; fish; terrestrial and aquatic turtles such as Mongolochelys and Nemegtemys; and the crocodylomorph Paralligator. They are similar to the original description with some degree of semiplantigradism. Even though representative fossils have only been found throughout Asia and North America, the range of Therizinosauridae is believed to have spanned much of the supercontinent of Laurasia based on several footprints and isolated remains in Europe and Africa. Near the region of the scapulocoracoid suture, on the coracoid, a large foramen is present. These impressions are composed by four toes with the first digit slightly smaller than the others which is attributed to therizinosaurids. It consisted of two phalanges and a large ungual. Therizinosaurus was a huge herbivorous theropod dinosaur from the end of the Cretaceous period. Nevertheless, an overall digging action would have been done with the foot claws because, since as in other maniraptorans, feathers on the arms would have interfered with this function. Lastly, though dendroolithid eggs are also attributed to megalosauroids, and therizinosaurids are not known from the Javkhlant Formation, it overlies the Bayan Shireh Formation, where other dendroolithid eggs and the therizinosaurs Enigmosaurus, Erlikosaurus and Segnosaurus were found. The adaptations to the inner-ear and forebrain of therizinosaurids likely served a number of functions, such as well-developed senses of smell, complex social behavior, increased alertness to the vocalizations of juveniles or even communicating with conspecifics, moreover, the large pneumatic chambers on the sensorial areas in the skulls of therizinosaurids (Erlikosaurus or Nothronychus mckinleyi) indicates that the tympanic systems would result in increased and optimal low frequency sound reception, possibly infrasound. [24] Two isolated teeth are known from Nothronychus and they are lanceolate-shaped, symmetrical, have moderate denticles, and strongly resemble those of Erlikosaurus. Wikimedia Commons With fingers that seemingly belong in a slasher flick, you'd think these creatures were designed to slice and dice hapless victims. [10] Although a new species of Nothronychus (N. graffami) was named in 2009. New, well-preserved finds such as Alxasaurus in 1993 and Beipiaosaurus in 1996 provided details about the bird-like pelvis, feet and skulls of primitive members. It was one of the last and the largest representative of its unique group, the Therizinosauria (formerly known as Segnosauria; the segnosaurs). [11] The skull of therizinosaurids was specialized as well, as it was likely capped off with a beak-like rostrum in the front. [8], For maniraptoran standards, Therizinosaurus obtained enormous sizes, estimated to have reached 9 to 10m (30 to 33ft) in length with estimated heights from 4 to 5m (13 to 16ft) and ponderous weights from 3t (3.3 short tons) to possibly over 5t (5.5 short tons). Perle referred MPC-D 100/45 to Therizinosaurus given that this specimen was found near the location of MPC-D 100/15 and was virtually similar to the described pes for Segnosaurus. [23] Other prominent paleontologists like Jacques Gauthier or Paul Sereno supported this vision. In this new monograph, he pointed out that the rib fragments in MPC-D 100/15 were more slender than the ones from the holotype, and identified MPC-D 100/16 and 100/17 as pertaining to digits I and III, respectively. For birds, an extended cochlea allows them to hear across an increased range of frequencies, suggesting a similar function in the ponderous therizinosaurids and also allowing them a good hearing and balance, which indeed, are traits better associated with carnivorous theropods. The lower end of the humerus was very expanded and flared. These dimensions that make the genus among the largest-known theropods. Therizinosaurid genus from the Late Cretaceous period, "Deinocheiridae, a new family of theropod dinosaurs", " (Therizinosauridae, Theropoda)", "Upper Cretaceous Djadokhta, Barun Goyot and Nemegt formations of Mongolia, including remarks on previous subdivisions", "A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora)", "Cranial anatomy of Erlikosaurus andrewsi (Dinosauria, Therizinosauria): new insights based on digital reconstruction", "The Slothful Claw: Osteology and Taphonomy of Nothronychus mckinleyi and N. graffami (Dinosauria: Theropoda) and Anatomical Considerations for Derived Therizinosaurids", "Hip heights of the gigantic theropod dinosaurs Deinocheirus mirificus and Therizinosaurus cheloniformis, and implications for museum mounting and paleoecology", "Why sauropods had long necks; and why giraffes have short necks", "Segnosauria, a new suborder of carnivorous dinosaurs", "Saurischian monophyly and the origin of birds", "A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight", "Middle Miocene Chalicotheriinae (Mammalia, Perissodactyla) from France, with a discussion on chalicotheriine phylogeny", "An unusual association of hadrosaur and therizinosaur tracks within Late Cretaceous rocks of Denali National Park, Alaska", "Morphological and functional diversity in therizinosaur claws and the implications for theropod claw evolution", "Functional space analyses reveal the function and evolution of the most bizarre theropod manual unguals", "The Surprisingly Strong Arms of the Therizinosaur Dinosaurs", "The first oviraptorosaur (Dinosauria: Theropoda) bonebed: evidence of gregarious behaviour in a maniraptoran theropod", "Diet preferences and climate inferred from oxygen and carbon isotopes of tooth enamel of Tarbosaurus bataar (Nemegt Formation, Upper Cretaceous, Mongolia)", "Ornithomimosaurs from the Nemegt Formation of Mongolia: manus morphological variation and diversity", "The Nemegt Basin One of the best field laboratories for interpreting Late Cretaceous terrestrial ecosystems", "Fresh-water ostracodes from the Nemegt Formation (Upper Cretaceous) of Mongolia", "Cretaceous soft-shelled turtles (Trionychidae) of Mongolia: new diversity, records and a revision", "A Review of Shamosuchus and Paralligator (Crocodyliformes, Neosuchia) from the Cretaceous of Asia", https://en.wikipedia.org/w/index.php?title=Therizinosaurus&oldid=1159199980, Short description is different from Wikidata, Articles containing Ancient Greek (to 1453)-language text, Creative Commons Attribution-ShareAlike License 4.0, Mounted forelimbs of specimen MPC-D 100/15 at, This page was last edited on 8 June 2023, at 21:55. It was bipedal and had a large, heavy, deep body, as evidenced by the wide pelvis, 2.5 meter (8 foot) long arms and legs that ended in four toes (three of which supported the animal's weight), which were tipped by short, curved claws. The habitat that the parents nested in was a semi-arid flood plain and the egg clutches were covered in organic-rich material during incubation as some extant archosaurs do today (crocodiles and megapode birds). Furthermore, they seem to derive from the dentary based on comparisons with the latter. The most mature embryo is represented by CAGS-01-IG-5, which had a clearly more developed ossification than alligator hatchlings. Out of a total of 15 clutches, at least 9 successfully hatched, which represents a nesting success rate of at least 60% for the entire site. Russell and Dong also noted the extreme similarities between Therizinosauridae and Segnosauridae and considered that the latter was a synonym of the former due to priority. It is also possible that Therizinosaurus was less capable of great precision in its movements than was Chalicotherium, due to the latter having more developed brain, dental and muscular capacities. During stages B and C the bones become slightly more articulated and ossified. The first remains of Therizinosaurus were found in 1948 by a Mongolian field expedition at the Gobi Desert and later described by Evgeny Maleev in 1954. [28] Parallel to this, the newly and also described Nanshiungosaurus was assigned to the Titanosaurinae by Dong Zhiming based on the assumption it was a sauropod genus. [7], In 2001, the new therizinosaurids Neimongosaurus and Nothronychus (N. mckinleyi) were described and named,[8][9] and in the following year Erliansaurus was also described and named. [1] The fossils remained with uncertainty among the scientific community; however, in 1970 Rozhdestvensky was one of the first paleontologists to suggest that Therizinosaurus was actually a theropod dinosaur instead of a turtle. They concluded that an average Therizinosaurus may have had approximately 3m (9.8ft) long legs. [25] Most therizinosaurids appear to have had a low tooth replacement rate or not able to loose them at all. Therizinosaurus are tall, herbivorous theropods native to dense forests. Furthermore, the lengthening of the cochlea, an adaptation which has independently evolved in a number of other theropod groups, is thought to further improve auditory acumen. Whereas Chalicotherium was more suited to hook branches, Therizinosaurus was better at pushing large clumps of foliage because of its long claws. Though the stocky claws of Alxasaurus resulted in low-stress magnitudes, the stress was greater with the curvature and elongation of the claws in Falcarius, Nothronychus and Therizinosaurus. The very long and deadly claws of this dinosaur were not used to battle, but also for foraging in the deep jungle. Three different functional scenarios were simulated for each claw morphology with a force of 400 N applied in each scenario: scratch/digging; hook-and-pull; and piercing. [56], Some of the first dendroolithid eggswhich are attributed to therizinosaurswere reported from the Bayan Shireh and Nanchao formations on the same year, 1997. Consequently, Segnosauria became a synonym of Therizinosauria. They concluded that therizinosaurs were more likely to be classified as maniraptoran theropods. But most of its relatives had small,. Slightly smaller members are represented by Nanshiungosaurus and Nothronychus, estimated at 55.3m (1617ft) long and 6001,000kg (0.601.00t) in weight, respectively. Therizinosaurus (Scythe Lizard) is a genus of therizinosaurid theropod dinosaur that lived in the Nemegt Formation, Mongolia, 70 million years ago, during the Maastrichtian stage of the Late Cretaceous Period. Most eggs have an average size of 7cm 9cm (70mm 90mm) and given these dimensions, they likely were laid by a medium-sized female. He concluded that Therizinosaurus was a theropod taxon since MPC-D 100/15 matched multiple theropodan characters. [28] In 1997, Rusell coined the infraorder Therizinosauria in order to contain all segnosaurs. Although several egg clutches were found, one was found containing 7 eggs of which 3 of them were preserving the embryos. The caudal vertebrae were stocky with stiff and rounded transverse projections. However, most of the footprint was made (apparently) by the fingers and a foot pad, indicating a more upright position of the metatarsals. Most dinosaurs in this mysterious family are known only from partial skeletons. Please refer to the appropriate style manual or other sources if you have any questions. The arms would have had to be able to extend the range of the animal to a point that could not be reached by the head if they were used for browsing and pulling down vegetation. The fibula was pinched to the bottom and very stiffened. [30], In 2010, Lindsay Zanno revised the taxonomy of therizinosaurs in extensive detail. [47], The group is also notable for adaptations to the structures of their ear. Some of the first dendroolithid eggs were found on the Bayan Shireh and Nanchao formations. The elongated hand claws of Therizinosaurus were more useful when pulling vegetation within reach rather than being used for active attack or defense because of their fragility, however, they may have had some role for intimidation. [2][12] In Segnosaurus, the deltopectoral crest (deltoid muscle attachment) was strongly built. Because the animals with this type of body plan are known to represent herbivores, the authors suggested this lifestyle for Therizinosaurus. Fossil specimens have been known since the 1950s, but their unusual combination of skeletal features (especially their teeth, hips, and toes) made their relationships to other dinosaur groups contentious. Therizinosaurs also lacked teeth in the front half of their upper jaws, and they had long necks, wrist bones similar to those of birds, widely spaced hips, a backward-pointing pubis bone, and four widely spread toes similar to those of sauropod dinosaurs.
Therizinosaurus | Dinosaur Protection Group Wiki | Fandom They considered this specimen to represent a Late Cretaceous representative of the Segnosauria, but not Therizinosaurus. This ability to extend their arms considerably forwards may have helped these therizinosaurids reach and grasp for foliage.
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