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79-496: It comprises continental clastic sediments consisting of light grey fine sandstones , coarse sandstones and glutenites as well as mottled claystones and siltstones . The fine-grained floodplain sediments and the coarse-grained sediments of the point bar formed a series of repeated frequently binary sedimentary rhythms. The “binary structure” of the sedimentary rhythms strongly indicates meandering stream deposits rather than braided river deposits as previously thought. As indicated by

158-506: A Late Cretaceous age based on U–Pb and paleomagnetic analyses, with a maximum depositional age of around 95.8 ± 6.2 million years ago . A 2022 study describing new ornithomimosaurian material, however, suggested that while the vertebrate faunal assemblage indicates that the age of the formation is likely Turonian based on its similarity to the Bissekty Formation of Uzbekistan , the invertebrate faunal assemblage indicates

237-479: A family to the exclusion of Deinocheiridae (today, Deinocheirus is recognized as an ornithomimosaur ). Barsbold retained Segnosaurus and Erlikosaurus in the family Segnosauridae in 1983, and named the new genus Enigmosaurus based on the previously undetermined segnosaurian pelvis, which he placed in its own family, Enigmosauridae, within Segnosauria. Though the structure of the pelvis of Erlikosaurus

316-597: A phylogenetic analysis of coelurosauria. In 1999, paleontologist Xing Xu and colleagues described a small, basal therizinosauroid from China, Beipiaosaurus , which confirmed that the group belonged among the coelurosaurian theropods, and that similarities with prosauropods had evolved independently. They published the first ever cladogram showing the evolutionary relationships of Therizinosauria, and demonstrated that Beipiaosaurus had features of more basal theropods, coelurosaurs, and therizinosaurs. Sereno found Therizinosaurs to be basal Ornithomimosaurian theropods during

395-548: A pterosaur has also been found in this formation. Archaeornithomimus "Partial manus, metatarsus, vertebrae, limb elements." An ornithomimosaur originally identified as Ornithomimus . Avimimidae spp. "Vertebrae and postcranial elements represented by at least six individuals." Avimimids at different growth stages. Caenagnathasia "Beak from lower jaws." An oviraptorosaur . Erliansaurus "Cervical vertebrae and postcranial elements." A therizinosauroid . Gigantoraptor "Lower jaws and much of

474-480: A thin section using a method like the Gazzi-Dickinson Method . This yields the relative percentages of quartz, feldspar, and lithic grains and the amount of clay matrix. The composition of a sandstone can provide important information on the genesis of the sediments when used with a triangular Q uartz, F eldspar, L ithic fragment ( QFL diagrams ). However, geologist have not been able to agree on

553-515: A 1989 conference abstract about sauropodomorph interrelationships, paleontologist Paul Sereno also considered segnosaurs as prosauropods, based on skull features. In a 1990 review article , Barsbold and paleontologist Teresa Maryańska found Segnosauria to be a rare and aberrant group of saurischians, in an unresolved position among sauropodomorphs and theropods, probably closer to the former. They therefore listed them as Saurischia sedis mutabilis ("position subject to change"). Though they agreed

632-535: A direct comparison between specimens is difficult to near impossible because there is no overlapping material (besides dorsal vertebrae) and the holotype of N. bohlini is apparently lost. Li and team disagree in that this species belong to Nanshiungosaurus and listed it as "Nanshiungosaurus" bohlini . Zanno in 2010 indicated that the anatomical traits that were originally used to characterize "N." bohlini are now known to be present in other therizinosaur taxa. Hartman with colleagues in 2019 recovered "N." bohlini as

711-441: A manner similar to large mammals that lived later on, such as chalicotheres , ground sloths , great apes , and giant pandas . Skin impressions from Beipiaosaurus indicate that therizinosaurs were covered with a coat of primitive, down -like feathers similar to those seen in the compsognathid Sinosauropteryx , as well as longer, simpler, quill-like feathers that may have been used in display. Barsbold and Perle named

790-422: A much later age ( Campanian - Maastrichtian ). The Iren Dabasu Formation is rich on dinosaur fauna, with multiple species described, in the other hand, mammals seem to be extremely absent. Compared, the fossil taxa between Iren Dabasu and Bayan Shireh are very similar, most notably therizinosaurs , tyrannosauroids , oviraptorosaurs and turtles . Although Gigantoraptor is the only described oviraptorosaur from

869-465: A new infraorder, they did show similarities with them. Since the Erlikosaurus specimen lacked a pelvis, the authors were unsure if that of the undetermined segnosaurian could belong to it, in which case they would consider it part of a separate family. Though Erlikosaurus was difficult to compare directly to Segnosaurus due to the incompleteness of their remains, Perle stated in 1981 that there

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948-634: A partial lower jaw with teeth (IVPP V11579) from the Early Jurassic -aged Lufeng Formation in Yunnan , and concluded that this specimen represented the oldest known record of a coelurosaurian theropod. Based mainly on teeth morphology, they indicated therizinosaur affinities. The specimen was later described in depth in 2001 and used as the holotype specimen for the new genus and species Eshanosaurus deguchiianus , named by Xing and colleagues. The team reinforced therizinosaur relationships, arguing that

1027-481: A partial tibia and partial right pes (foot) largely lacking metatarsals. Dong referred it to the genus mainly based on similarities between the unguals of this specimen and those of C. tashuikouensis . Barsbold and Maryanska in 1990 considered C. zheziangensis as a tentative segnosaur (later known as therizinosaurs) based on its relatively short and robust pedal phalanges and enlarged, strongly curved unguals, mostly similar to Segnosaurus . As this taxon may lie outside

1106-659: A phylogenetic analysis and recovered it within Therizinosauroidea in a polytomy with Alxasaurus , Enigmosaurus and therizinosaurids. In 1997 Dong Zhiming and You Hailu named and described a supposed second species of Nanshiungosaurus , N. bohlini , based on specimen IVPP V 11116 found in 1992 at Early Cretaceous strata from the Zhonggou Formation , Xinminbao Group . It consists of 11 cervical and 5 dorsal vertebrae with some ribs . In order to contain both N. brevispinus and N. bohlini they coined

1185-478: A sandstone goes through as the degree of kinetic processing of the sediments increases. Dott's (1964) sandstone classification scheme is one of many such schemes used by geologists for classifying sandstones. Dott's scheme is a modification of Gilbert's classification of silicate sandstones, and it incorporates R.L. Folk's dual textural and compositional maturity concepts into one classification system. The philosophy behind combining Gilbert's and R. L. Folk's schemes

1264-556: A segnosaurian identity for Therizinosaurus . He also placed segnosauria within Phytodinosauria , a superorder that paleontologist Robert Bakker had created in 1985 to retain all plant-eating dinosaurs. In a 1986 study of the interrelationships of saurischian dinosaurs, paleontologist Jacques Gauthier concluded that segnosaurs were prosauropods. While he conceded they had similarities with ornithischians and theropods, he proposed these featured had evolved independently. In

1343-629: A segnosaurid, and reported a partial pelvis of an undetermined segnosaurian, both from the same formation as Segnosaurus . Combined, the specimens provided relatively complete data on this group; they were united by their opisthopubic pelvis, slender mandible, and the toothless front of their jaws. Barsbold and Perle stated that though some of their features resembled those of ornithischians and sauropods, these similarities were superficial, and were distinct when examined in detail. While they were essentially different from other theropods (perhaps due to diverging from them relatively early), and therefore warranted

1422-462: A set of boundaries separating regions of the QFL triangle. Visual aids are diagrams that allow geologists to interpret different characteristics of a sandstone. For example, a QFL chart can be marked with a provenance model that shows the likely tectonic origin of sandstones with various compositions of framework grains. Likewise, the stage of textural maturity chart illustrates the different stages that

1501-564: A therizinosaurid in a clade joined by Segnosaurus and Nothronychus . Around 2005 partial therizinosaur material was collected from the Laijia Formation and later used to represent "Tiantaiosaurus sifengensis" (alternatively "Tiantaisaurus"), which is a currently unpuslihed and informal therizinosaur taxon. Qian and team in 2012 noted that a whole manuscript describing the taxon was written in 2007 but never officially published. In 1998 Zhao Xijin and Xu Xing briefly discovered

1580-666: A tooth from the Bathonian -aged Chipping Norton Limestone in England , to the Therizinosauroidea, making this the oldest record of Therizinosauroidea and also the first record of Therizinosauroidea in Europe . In 1979 Dong Zhiming named a new species of the megalosaurid Chilantaisaurus , C. zheziangensis , based on specimen ZhM V.001. This specimen was recovered in 1972 from the Tangshang Formation and consists of

1659-445: A twofold classification: Cement is what binds the siliciclastic framework grains together. Cement is a secondary mineral that forms after deposition and during burial of the sandstone. These cementing materials may be either silicate minerals or non-silicate minerals, such as calcite. Sandstone that becomes depleted of its cement binder through weathering gradually becomes friable and unstable. This process can be somewhat reversed by

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1738-502: Is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains, cemented together by another mineral. Sandstones comprise about 20–25% of all sedimentary rocks . Most sandstone is composed of quartz or feldspar , because they are the most resistant minerals to the weathering processes at the Earth's surface. Like uncemented sand , sandstone may be imparted any color by impurities within

1817-837: Is a distinction that can be recognized in the field . In turn, the distinction between an orthoquartzite and a metaquartzite is the onset of recrystallization of existing grains. The dividing line may be placed at the point where strained quartz grains begin to be replaced by new, unstrained, small quartz grains, producing a mortar texture that can be identified in thin sections under a polarizing microscope. With increasing grade of metamorphism, further recrystallization produces foam texture , characterized by polygonal grains meeting at triple junctions, and then porphyroblastic texture , characterized by coarse, irregular grains, including some larger grains ( porphyroblasts .) Sandstone has been used since prehistoric times for construction, decorative art works and tools. It has been widely employed around

1896-640: Is a therizinosaur. In 2012 the Mongolian Academy of Sciences recovered a partial theropod specimen from the Bayan Shireh Formation at the Urlibe Khudak (also Ulribe Khuduk) locality. The specimen was in a 2015 abstract by Yoshitsugu Kobayashi and team briefly described and identified as a new therizinosaur taxon distinct from the concurring Enigmosaurus , Erlikosaurus and Segnosaurus . The Urlibe Khudak therizinosaur

1975-412: Is defined as Alxasaurus , Enigmosaurus , Erlikosaurus , Nanshiungosaurus , Segnosaurus , Therizinosaurus , and all taxa closer to them than to oviraptorosaurs , ornithomimids , and troodontids . Paul Sereno , in 2005, modified this definition to the most inclusive clade containing Therizinosaurus but not Ornithomimus , Oviraptor , Shuvuuia , Tyrannosaurus , or Troodon . When it

2054-523: Is likely formed during eogenesis. Deeper burial is accompanied by mesogenesis , during which most of the compaction and lithification takes place. Compaction takes place as the sand comes under increasing pressure from overlying sediments. Sediment grains move into more compact arrangements, ductile grains (such as mica grains) are deformed, and pore space is reduced. In addition to this physical compaction, chemical compaction may take place via pressure solution . Points of contact between grains are under

2133-496: Is most notably for its manual morphology which consist of only two fingers ( didactyly ), in a similar manner to tyrannosaurids . Such trait makes it the only known two-fingered therizinosaur. Therizinosaurs spanned a large range of sizes, from the smaller Beipiaosaurus (2.2 m (7.2 ft) long) and Jianchangosaurus (2 m (6.6 ft) long) to the large-sized 6–7 m (20–23 ft) long Segnosaurus and Suzhousaurus . Therizinosaurus itself, obtained

2212-431: Is redeposited in the unstrained pore spaces. Mechanical compaction takes place primarily at depths less than 1,000 meters (3,300 ft). Chemical compaction continues to depths of 2,000 meters (6,600 ft), and most cementation takes place at depths of 2,000–5,000 meters (6,600–16,400 ft). Unroofing of buried sandstone is accompanied by telogenesis , the third and final stage of diagenesis. As erosion reduces

2291-443: Is that it is better able to "portray the continuous nature of textural variation from mudstone to arenite and from stable to unstable grain composition". Dott's classification scheme is based on the mineralogy of framework grains, and on the type of matrix present in between the framework grains. In this specific classification scheme, Dott has set the boundary between arenite and wackes at 15% matrix. In addition, Dott also breaks up

2370-777: The Global Heritage Stone Resource . In some regions of Argentina, the orthoquartzite-stoned facade is one of the main features of the Mar del Plata style bungalows. Therizinosaurs Therizinosaurs ( ; once called segnosaurs ) are an extinct group of large herbivorous theropod dinosaurs whose fossils have been mainly discovered from Cretaceous deposits in Asia and North America . Potential fragmentary remains have also been found in Jurassic deposits of Asia and Europe . Various features of

2449-723: The Gobi Desert , the dinosaur fauna of the Iren Dabasu Formation includes tyrannosauroids , ornithomimids , therizinosaurs and oviraptorosaurs . However, strong evidence coming from biostratigraphic occurrences seems to support a correlation with the Bayan Shireh Formation, at least, with the upper boundary. For instance, both formations bear similar dinosaur taxa, such as therizinosaurs ( Erlikosaurus , Segnosaurus , Erliansaurus or Neimongosaurus ) and ornithomimosaurs ( Garudimimus or Archaeornithomimus ), these similarities are even more intensified by

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2528-498: The percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs . Quartz-bearing sandstone can be changed into quartzite through metamorphism , usually related to tectonic compression within orogenic belts . Sandstones are clastic in origin (as opposed to either organic , like chalk and coal , or chemical , like gypsum and jasper ). The silicate sand grains from which they form are

2607-567: The "bird-hipped" ornithischians . Among the most striking characteristics of therizinosaurs are the enormous claws on their hands, which reached lengths of around one meter in Therizinosaurus . The unusual range of motion in therizinosaur forelimbs, which allowed them to reach forward to a degree other theropods could not achieve, also supports the idea that they were mainly herbivorous. Therizinosaurs may have used their long reach and strongly curved claws to grasp and shear leafy branches, in

2686-630: The Bayan Shireh Formation) are indicatives of a river system with connections to the ocean. Based on the ostracod and charophyte assemblages of the Iren Dabasu Formation, Itterbeeck et al. 2005 suggested a potential correlation with those of the Nemegt Formation , making its age Late Campanian to Early Maastrichtian . However, vertebrates point to an older date than the Campanian-Maastrichtian ages,

2765-528: The Nanshiungosauridae family. Dong and Yu presented no clear evidence regarding the assignment of this new species to Nanshiungosaurus . Li and colleagues in their 2007 description of Suzhousaurus pointed out that N. bohlini might be synonymous with the former, as both are found in the same geological group and also incompletely known. As per terms of taxonomic priority , the species name would be Suzhousaurus bohlini . However, they noted that

2844-491: The application of tetraethyl orthosilicate (Si(OC 2 H 5 ) 4 ) which will deposit amorphous silicon dioxide between the sand grains. The reaction is as follows. Pore space includes the open spaces within a rock or a soil. The pore space in a rock has a direct relationship to the porosity and permeability of the rock. The porosity and permeability are directly influenced by the way the sand grains are packed together. Sandstones are typically classified by point-counting

2923-597: The borders" of this group, but opted to retain them within Theropoda. In the same year, Barsbold stated that the segnosaurian pelvis deviated strongly from the theropod norm, and found the configuration of their ilia generally similar to those of sauropods . Paleontologist Gregory S. Paul concluded in 1984 that segnosaurs did not possess any theropodan features, but were instead derived, late-surviving Cretaceous prosauropods with adaptations similar to those of ornithischians. He found segnosaurs similar to prosauropods in

3002-485: The common descent of these groups as support for the idea that dinosaurs were a monophyletic (natural) group, which was contested by some paleontologists at the time (who instead thought different dinosaurs groups evolved independently from thecodonts ). Paleontologist David B. Norman considered Paul's idea a contentious claim "bound to provoke much argument" in 1985. In 1988, Paul maintained that segnosaurs were late surviving ornithischian-like prosauropods, and proposed

3081-473: The common minerals most resistant to weathering processes at the Earth's surface, as seen in the Goldich dissolution series . Framework grains can be classified into several different categories based on their mineral composition: Matrix is very fine material, which is present within interstitial pore space between the framework grains. The nature of the matrix within the interstitial pore space results in

3160-456: The depositional environment, older sand is buried by younger sediments, and it undergoes diagenesis . This mostly consists of compaction and lithification of the sand. Early stages of diagenesis, described as eogenesis , take place at shallow depths (a few tens of meters) and are characterized by bioturbation and mineralogical changes in the sands, with only slight compaction. The red hematite that gives red bed sandstones their color

3239-407: The depth of burial, renewed exposure to meteoric water produces additional changes to the sandstone, such as dissolution of some of the cement to produce secondary porosity . Framework grains are sand-sized (0.0625-to-2-millimeter (0.00246 to 0.07874 in) diameter) detrital fragments that make up the bulk of a sandstone. Most framework grains are composed of quartz or feldspar , which are

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3318-399: The detailed morphology of its limbs linked it to Therizinosaurus and segnosaurs. Since it preserved both fore and hindlimbs, Alxasaurus showed that Perle's assignment of segnosaurian hindlimbs to Therizinosaurus was probably correct. Russell and Dong therefore proposed that Segnosauridae was a junior synonym of Therizinosauridae (since the latter name was older), with Alxasaurus being

3397-446: The different types of framework grains that can be present in a sandstone into three major categories: quartz, feldspar, and lithic grains. When sandstone is subjected to the great heat and pressure associated with regional metamorphism , the individual quartz grains recrystallize, along with the former cementing material, to form the metamorphic rock called quartzite . Most or all of the original texture and sedimentary structures of

3476-441: The discovery of Gigantoraptor and the giant unnamed caenagnathid from Bayan Shireh. In addition, the potential discovery of Alectrosaurus in both formations seems to be another indicative of a correlation. Consequently, Averianov and Sues estimated the formation to be Santonian in age, roughly about 86 million and 83 million years ago. However, palynological correlations suggest a Maastrichtian age. Guo et al. 2018 supported

3555-460: The fluvial and lacustrine sedimentation, the Iren Dabasu Formation was a large floodplain terrain with braided rivers and meanders that supported extensive vegetation, evidenced on the prominent palaeosol development and the numerous remains from herbivorous dinosaurs. Egg nests, caliche and paleosols seem to indicate periodic subaerial intervals, in addition, the presence of plesiosaur and hybodont shark remains (which are also known in

3634-873: The forelimbs, skull and pelvis unite these finds as both theropods and maniraptorans , making them relatives of birds . The name of the representative genus, Therizinosaurus , is derived from the Greek θερίζω ( therízō , 'to reap' or 'scythe') and σαῦρος ( saûros , 'lizard'). The older representative, Segnosaurus , is derived from the Latin sēgnis ('slow') and the Greek σαῦρος . Therizinosaurs were long considered an enigmatic group, whose mosaic of features resembling those of various different dinosaur groups, and scarcity of their fossils, led to controversy over their evolutionary relationships for decades after their initial discovery. The first genus, Therizinosaurus ,

3713-422: The formation, Funston et al. 2019 described a new avimimid bonebed containing numerous individuals at different growth stages. Nevertheless, the fossils lacked enough diagnosis to be confined to a separate genus and species. Deinonychosaurs are not very common across the formation, however an indeterminate troodontid about the size of Saurornithoides is known from three isolated specimens. An isolated humerus of

3792-416: The genus Chilantaisaurus , they listed this species as "Chilantaisaurus" zheziangensis . Although Glut (1997) stated this specimen may have been based on part of the holotype of Nanshiungosaurus brevispinus (based on a pers. comm from Dong to Molnar in 1984), Dong in 1979 described both taxa from largely different formations and localities. Zanno in 2010 argued that the notorious side to side compression of

3871-433: The greatest strain, and the strained mineral is more soluble than the rest of the grain. As a result, the contact points are dissolved away, allowing the grains to come into closer contact. Lithification follows closely on compaction, as increased temperatures at depth hasten deposition of cement that binds the grains together. Pressure solution contributes to cementing, as the mineral dissolved from strained contact points

3950-404: The group Oviraptorosauria (since they found Maniraptora , the conventional grouping of these, invalid, and the higher level taxonomy of theropods was in flux at the time). The synonymy of Segnosauridae with Therizinosauridae was accepted by Perle himself and co-authors of a redescription of the holotype skull of Erlikosaurus in 1994, and they considered therizinosaurs maniraptoran theropods,

4029-447: The group Segnosauria as an infraorder of Theropoda in 1980. Dong Zhiming went further, placing the segnosaurs in their own order, Segnosaurischia . This name has been abandoned since the discovery that segnosaurs are a specialized group within the suborder Theropoda. Clark et al. 2004 considered Segnosaurischia a synonym of Therizinosauroidea. The clade Therizinosauria was first coined by Dale Russell in 1997—effectively replacing

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4108-524: The group that also includes modern birds (since they did find Maniraptora to be valid through their analysis). They also discussed the previous ornithischian and sauropod hypotheses for therizinosaur affinities in detail and demonstrated various faults with them. Palaeontologist Lev Alexandrovich Nessov rejected that therizinosaurs were theropods in 1995, and instead considered them a distinct group within saurischia. In 1996, paleontologist Thomas R. Holtz Jr. found therizinosaurs to group with oviraptorosaurs in

4187-543: The group were also still uncertain by 2010, when Zanno conducted the most detailed phylogenetic analysis of the Therizinosauria until that point. She cited the inaccessibility, damage, potential loss of holotype specimens, scarcity of cranial remains, and fragmentary specimens with few overlapping elements as the most significant obstacles to resolving the evolutionary relationships within the group. Wills, Underwood & Barrett (2023) assigned specimen GLCRM G167-32,

4266-442: The hardness of individual grains, uniformity of grain size and friability of their structure, some types of sandstone are excellent materials from which to make grindstones , for sharpening blades and other implements. Non-friable sandstone can be used to make grindstones for grinding grain, e.g., gritstone . A type of pure quartz sandstone, orthoquartzite, with more of 90–95 percent of quartz, has been proposed for nomination to

4345-439: The hindlimbs assigned to Therizinosaurus in 1982 were segnosaurian, they did not consider this justification for Therizinosaurus itself being a segnosaur, since it was only known from forelimbs. In 1993, paleontologists Dale A. Russell and Dong Zhi-Ming described the new genus Alxasaurus from China, at the time the most complete large theropod from its time and place. While it was similar to prosauropods in some respects,

4424-491: The minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Because sandstone beds can form highly visible cliffs and other topographic features, certain colors of sandstone have become strongly identified with certain regions, such as the red rock deserts of Arches National Park and other areas of the American Southwest . Rock formations composed of sandstone usually allow

4503-748: The morphology of their snout, mandible, and hindfoot, and to ornithischians in their cheek, palate, pubis, and ankle, and similar to early dinosaurs in other respects. He proposed that ornithischians were descended from prosauropods, and that the segnosaurs were an intermediate relict of this transition, which supposedly took place during the Triassic period . In this way, he considered segnosaurians to be to herbivorous dinosaurs what monotremes are to mammals. He did not rule out that segnosaurs could be derived from theropods, or that segnosaurs, prosauropods and ornithischians were each independently derived from early dinosaurs, but found these options unlikely. He considered

4582-523: The most completely known representative so far, providing a better understanding of the group. They also named the new higher taxonomic rank Therizinosauroidea to contain Alxasaurus and Therizinosauridae (since the new genus was somewhat different from its relatives), which they placed in the group Tetanurae within Theropoda. They considered therizinosaurs most closely related to ornithomimids, troodontids, and oviraptorids, which they placed together in

4661-493: The much lower temperatures and pressures associated with diagenesis of sedimentary rock, but diagenesis has cemented the rock so thoroughly that microscopic examination is necessary to distinguish it from metamorphic quartzite. The term orthoquartzite is used to distinguish such sedimentary rock from metaquartzite produced by metamorphism. By extension, the term orthoquartzite has occasionally been more generally applied to any quartz-cemented quartz arenite . Orthoquartzite (in

4740-874: The name Therizinosauria to remain in use for the larger group comprising all therizinosaurs. This definition was followed by Sereno (2005), Zanno et al. (2009) and Zanno (2010), though other subsequent studies, such as Senter (2007, 2012) have continued to use Therizinosauroidea for the therizinosaur "total group". The cladogram below follows the extensive phylogenetic analysis of the Therizinosauria by Lindsay E. Zanno in 2010. Falcarius [REDACTED] Beipiaosaurus [REDACTED] Alxasaurus Erliansaurus [REDACTED] Neimongosaurus [REDACTED] Enigmosaurus [REDACTED] Suzhousaurus [REDACTED] Nothronychus [REDACTED] Nanshiungosaurus [REDACTED] Segnosaurus [REDACTED] Erlikosaurus [REDACTED] Therizinosaurus [REDACTED] Below

4819-464: The narrow sense) is often 99% SiO 2 with only very minor amounts of iron oxide and trace resistant minerals such as zircon , rutile and magnetite . Although few fossils are normally present, the original texture and sedimentary structures are preserved. The typical distinction between a true orthoquartzite and an ordinary quartz sandstone is that an orthoquartzite is so highly cemented that it will fracture across grains, not around them. This

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4898-559: The older name Segnosauria, which has not yet been defined as a clade—to contain all therizinosaurian dinosaurs. The superfamily Therizinosauroidea was first coined in 1993 as a superfamily with no phylogenetic definition. The family Therizinosauridae had been established by Maleev in 1954 to include only the bizarre, giant-clawed theropod Therizinosaurus . Subsequent analyses have proven this family to be more diverse and synonymous with Segnosauridae. The following taxonomy follows Zanno 2010, unless otherwise noted. Therizinosauria

4977-1184: The postcranial elements with very elongated hindlimbs." A giant oviraptorosaur. Neimongosaurus "Two specimens with most of the axial column, many limb and girdle elements, and a partial dentary." A therizinosauroid. Therizinosauridae "Right humerus with a phalanx and ungual." A therizinosaurid similar to Segnosaurus and initially attributed to Alectrosaurus olseni . Troodontidae "Right and left metatarsals represented by three specimens." A troodontid . Bactrosaurus B. johnsoni "Cranial and postcranial material represented by more than eight specimens." A hadrosauroid . Gilmoreosaurus G. mongoliensis "Partial cranial and postcranial elements represented by more than ten specimens". A hadrosauroid originally identified as Mandschurosaurus . Spheroolithus S. irenensis "Egg fossils." Sonidosaurus "Numerous cervical, dorsal and caudal vertebrae and some postcranial elements." A titanosaur . Aquillapollenites sp. Angiosperm pollen . Buttinia sp. Angiosperm pollen. Cranwellia sp. Angiosperm pollen. Momipites sp. Sandstone Sandstone

5056-638: The product of physical and chemical weathering of bedrock. Weathering and erosion are most rapid in areas of high relief, such as volcanic arcs , areas of continental rifting , and orogenic belts . Eroded sand is transported by rivers or by the wind from its source areas to depositional environments where tectonics has created accommodation space for sediments to accumulate. Forearc basins tend to accumulate sand rich in lithic grains and plagioclase . Intracontinental basins and grabens along continental margins are also common environments for deposition of sand. As sediments continue to accumulate in

5135-471: The same rank, possibly at the level of infraorder within Saurischia (one of the two main divisions of dinosaurs, the other being Ornithischia ). In 1980, Barsbold and Perle named the new theropod infraorder Segnosauria, containing only Segnosauridae. In the same article, they named the new genus Erlikosaurus (known from a well-preserved skull and partial skeleton) which they tentatively considered

5214-417: The sandstone are erased by the metamorphism. The grains are so tightly interlocked that when the rock is broken, it fractures through the grains to form an irregular or conchoidal fracture. Geologists had recognized by 1941 that some rocks show the macroscopic characteristics of quartzite, even though they have not undergone metamorphism at high pressure and temperature. These rocks have been subject only to

5293-571: The supposed deposition of ostracods were likely due to climatic conditions rather than age. The turtle Khunnuchelys is known from both Iren Dabasu and Bayan Shireh equivalent units such as the Bostobe and Bissekty . In addition, a giant caenagnathid similar to Gigantoraptor is now known from the Bayan Shireh Formation at the locality of Tsagan Teg. Like the coeval Bayan Shireh Formation (and possibly Javkhlant Formation ) in

5372-417: The teeth morphology of Eshanosaurus can be differentiated from sauropodomorphs . In the same 2001 however, James I. Kirkland and Douglas G. Wolfe noted that the holotype of Eshanosaurus preserves traits only seen in sauropodomorphs. Paul M. Barrett in 2009 examined the specimen in detail, noting six features shared with therizinosaurs but not exhibited by prosauropods, agreeing in that Eshanosaurus

5451-484: The theropod families Deinocheiridae and Therizinosauridae (then only known from the genera Deinocheirus and Therizinosaurus , both mainly represented by large forelimbs found in Mongolia) by features of their humeri and hand claws. Later in 1979, Barsbold and Perle found the pelvic features of segnosaurids and dromaeosaurids so different from those of "true" theropods that they should be separated into three taxa of

5530-519: The top dimensions of the group, growing up to 10 m (33 ft) long and weighing over 5 t (11,000 lb), dimensions that make the genus among the largest-known theropods . Therizinosaurs had a very distinctive, often confusing set of characteristics. Their long necks, wide torsos, and hind feet with four toes used in walking resembled those of basal sauropodomorph dinosaurs. Their unique hip bones, which pointed backwards and were partially fused together, initially reminded paleontologists of

5609-408: The unguals reflect therizinosaur affinities, although examinations to the preserved tibia are required for further conclusions. In 2012 Mai-Ping Qian and colleagues placed "C". zheziangensis in the family Therizinosauridae based on its pes morphology, which is consistent to other therizinosaurids. They also illustrated most of the preserved pes. Hartman with team in 2019 added "C". zheziangensis to

5688-626: The world in constructing temples, churches, homes and other buildings, and in civil engineering . Although its resistance to weathering varies, sandstone is easy to work. That makes it a common building and paving material, including in asphalt concrete . However, some types that have been used in the past, such as the Collyhurst sandstone used in North West England , have had poor long-term weather resistance, necessitating repair and replacement in older buildings. Because of

5767-487: The year 1999. By the early 21st century, many more therizinosaur taxa had been discovered, including outside Asia (the first being Nothronychus from North America), as well as various basal taxa that helped understanding of the early evolution of the group (such as Falcarius , also from North America). Therizinosaurs were not considered as rare or aberrant anymore, but more diverse than previously thought (including in size), and their classification as maniraptoran theropods

5846-479: Was first defined by Zhang et al. in 2001, as the clade containing all theropods more closely related to Therizinosaurus than to birds. This definition, however, defines the same group as the pre-existing Therizinosauria. An alternate definition was given by Clark in 2004 (as the last common ancestor of Therizinosaurus and Beipiaosaurus and all its descendants), comprising a narrower group that excludes more primitive therizinosaurs, such as Falcarius , and allows

5925-476: Was generally accepted. The placement of Therizinosauria within Maniraptora continued to be unclear; in 2007, paleontologist Alan H. Turner and colleagues found them to group with oviraptorosaurs, while Zanno and colleagues found them to be the most basal clade within Maniraptora in 2009, bracketed by Ornithomimosauria and Alvarezsauridae . Despite the additional fossil material, the interrelations within

6004-452: Was later realized that Therizinosaurus was an advanced therizinosaur more related to Alxasaurus than other dinosaur lineages, Therizinosauroidea was coined to include Alxasaurus and Therizinosauridae, and has largely replaced the use of the older name Segnosauria in phylogenetic studies, mainly because of the association of the name Segnosauria with the discredited idea that these animals were relatives of prosauropods . Therizinosauroidea

6083-489: Was no justification for separating it into another family. In 1982, Perle reported hindlimb fragments similar to those of Segnosaurus , and assigned them to Therizinosaurus , whose forelimbs had been found in almost the same location. He concluded that Therizinosauridae, Deinocheiridae, and Segnosauridae, which all had enlarged forelimbs, represented the same taxonomic group. Segnosaurus and Therizinosaurus were particularly similar, leading Perle to suggest they belonged in

6162-485: Was originally identified as a turtle when described from forelimb elements in 1954. Perle noted in 1979 that the Segnosaurus fossils were possibly representative of a new family of dinosaurs, which he tentatively classified as theropods (traditionally thought of as the "meat-eating" dinosaurs). He named the family Segnosauridae, with Segnosaurus as type genus and sole member. He distinguished Segnosauridae from

6241-487: Was unknown, Barsbold considered it unlikely the Enigmosaurus pelvis belonged to it, since Erlikosaurus and Segnosaurus were so similar in other respects, while the pelvis of Enigmosaurus was very different from that of Segnosaurus . Barsbold found that segnosaurids were so peculiar compared to more typical theropods that they were either a very significant deviation in theropod evolution, or that they went "beyond

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