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-Mapusaurus roseae n. gen., n. sp.: A, B, left maxilla (MCF-PVPH-108.169); A, lateral view; B, medial view; C, D, right maxilla (MCF-PVPH-108.115); C, lateral view; D, medial view; E-G, left maxillary fragment (MCF-PVPH-108.11); E, posterior view; F, medial view; G, anterior view. Abbreviations: 1, 3, 12, first, third and 12th alveoli; af, antorbital fossa; amp, anteromedial process; ap, ascending process; ma, maxillary antrum; mf, maxillary fenestra; pa, postantral strut; pmr, promaxillary recess; ps, palatal shelf. Scale bars: 10 cm.

-Mapusaurus roseae n. gen., n. sp.: A, B, left maxilla (MCF-PVPH-108.169); A, lateral view; B, medial view; C, D, right maxilla (MCF-PVPH-108.115); C, lateral view; D, medial view; E-G, left maxillary fragment (MCF-PVPH-108.11); E, posterior view; F, medial view; G, anterior view. Abbreviations: 1, 3, 12, first, third and 12th alveoli; af, antorbital fossa; amp, anteromedial process; ap, ascending process; ma, maxillary antrum; mf, maxillary fenestra; pa, postantral strut; pmr, promaxillary recess; ps, palatal shelf. Scale bars: 10 cm.

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A new carcharodontosaurid theropod from the Huincul Formation (Aptian-Cenomanian, Upper Cretaceous) of Neuquén Province, Argentina, is described. Approximately the same size as Giganotosaurus carolinii Coria & Salgado, 1995, Mapusaurus roseae n. gen., n. sp. is characterized by many features including a deep, short and narrow skull with relatively...

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... The nasals are covered by well-developed rugosities and bumps except for the smooth anterolateral area that surrounds the external nares, as in other carcharodontosaurines. 7,9 The lacrimal is ornamented with ridges and furrows on its lateral surface and rounded projections along the dorsal margin. A robust brow horn projects laterally from the postorbital and is marked by a vascular horizontal groove extending across its lateral face as in other derived carcharodontosaurids. 6,7 A dorsoventrally elongated ridge extends along the posterior edge of the quadrate ans, accessory neural spine; ast, astragalus; ap, ascending process; cal, calcaneum; co, coracoid; fh, femoral head; fi, fibula; gf, glenoid fossa; h, humerus; ha, hemal arch; il, ilium; is, ischium; j, jugal; l, lacrimal; mx, maxilla; n, nasal; ns, neural spine; pb, pubic boot; pf, pubic foramen; po, postorbital; prz, prezygapophysis; r, radius; sc, scapula; sq, squamosal; ti, tibia; tp, transverse process; u, ulna. ...
... The ischial shaft is straight as in Acrocanthosaurus, 3 unlike the curved shaft present in Mapusaurus. 9 The femur has a strongly upturned and slightly anteromedially oriented femoral head. The tibia has an anterodorsally projected cnemial crest, with a subrectangular outline in lateral view. ...
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... Such pneumatopores become progressively larger dorsally, forming a honey-comb structure. This condition is observed only in this theropod while other theropods shows apneumatic ribs (such as Allosaurus, carcharodontosaurids, tyrannosaurids, non-avian paravians, among others; [43][44][45][46][47][48] or shows only one pneumatic opening (like abelisaurids; 49 ). The posterior surface of the rib head is covered with strong rugosities. ...
... On the contrary, carcharodontosaurids show taller proximal caudal neural spines 56 . In addition, the dorsoventral height/anteroposterior width ratio of the proximal caudal vertebrae of megaraptorids, tyrannosaurids and Allosaurus is less than 2 6,33,43,44 , while in carcharodontosaurids (such as Mapusaurus and Concavenator 48,56 ) the ratio ranges between 2 and 4. ...
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... While citing a number of caveats, they concluded that given the large number of occurrences of certain dinosaurs in close associations and the rarity of events ending in the formation of monodominant bonebeds, such sites "must be considered excellent evidence for those animals being naturally aggregated at the time of death" (Hone et al. 2014a, p. 17). Indeed, such bonebeds are well documented for ceratopsids (e.g., Zhao et al. 2007), ornithopods (e.g., Horner 1982Forster 1990;Rogers 1990), theropods (e.g., Schwartz and Gillette 1994;Currie 1998;Kobayashi and L€ u 2003;Coria and Currie 2006), and sauropods (e.g., Dong 1990;Coria 1994;Winkler et al. 2000;Sander et al. 2006). Examples of monodominant bonebeds or "clusters" (sensu Zhao et al. 2014) dominated by juveniles or subadults include those reported for some lambeosaurine hadrosaurs (Varricchio and Horner 1993;Scherzer and Varricchio 2010;Holland et al. 2021); the ornithomimid Sinornithomimus dongi (Kobayashi and L€ u 2003;Varricchio et al. 2008); the small, nonavian theropods, Bicentenaria argentina (Novas et al. 2012) and Aniksosaurus darwini (Ibiricu et al. 2013) from Patagonia; at least some sauropods (Myers and Fiorillo 2009); Tenontosaurus (Forster 1990); the ankylosaurid Pinacosaurus (Currie et al. 2011); and the ceratopsians Psittacosaurus sp. ...
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A monodominant Gryposaurus sp. bonebed in the lower unit of the Campanian Oldman Formation of southern Alberta is the oldest hadrosauroid bonebed documented in the province and the first described from the formation. The sedimentology of the locality and the taphonomy of the hadrosaurid material indicates that the bonebed represents an assemblage of juvenile-sized individuals that were probably transported only a short distance from where they died to where they were finally deposited and preserved in a fine-grained mudstone within an overbank sequence. Histological examination of six limb elements confirms that all individuals are juveniles, with two age classes (<1 and <2 years of age at the time of death) that likely died in the same event. Bone microstructure data indicate that Gryposaurus experienced rapid growth over the 2-year life spans documented, equivalent to other Late Cretaceous hadrosaurids in North America. The parautochthonous nature of the bonebed, and the lack of small neonate (newborn) material and almost complete lack of large adult material, suggests that the bonebed represents a segregated group of juveniles. This group of immature individuals may have been an autonomous unit that had separated itself from a larger social grouping, possibly in an effort to increase their survivability.
... The Tyrants Aisle dinosaur tracksite close association between these two trackways, their similar pace lengths, and the observation that small tridactyl theropod-like tracks are rare elsewhere across the~1, 400 m 2 tracksite (n�4, not including these trackways), we conclude that the two trackmakers of Th.Tw4.71A-70-A and Th.Tw5.71-A-72-A were probably travelling together. These data are consistent with trackway (e.g., [17,[127][128][129][130][131]) and skeletal (e.g., [132][133][134][135][136]) evidence from elsewhere that indicates gregariousness-whether periodic or sustained-was present in a range of theropod clades and body sizes. ...
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... Comparisons: These isolated specimens, found in multiple localities, are all identifiable as carcharodontosaurs based on numerous apomorphies. The teeth possess many characters found in the Carcharodontosauria, including transverse enamel undulations, basally inclined interdenticular sulci, and S-shaped mesiodistal profile (Benson, Carrano & Brusatte, 2010;Coria & Currie, 2006;Currie & Azuma, 2006;Currie & Carpenter, 2000;Harris, 1998;Naish, 2011;Novas et al., 2013;Sereno et al., 1996). While tall and moderately recurved, this tooth morphotype lacks the extensive anterior carina, extreme labiolingual compression, and large size observed in carcharodontosaurids such as Mapusaurus, Giganotosaurus, and Carcharodontosaurus (Coria & Currie, 2006;Novas et al., 2013). ...
... The teeth possess many characters found in the Carcharodontosauria, including transverse enamel undulations, basally inclined interdenticular sulci, and S-shaped mesiodistal profile (Benson, Carrano & Brusatte, 2010;Coria & Currie, 2006;Currie & Azuma, 2006;Currie & Carpenter, 2000;Harris, 1998;Naish, 2011;Novas et al., 2013;Sereno et al., 1996). While tall and moderately recurved, this tooth morphotype lacks the extensive anterior carina, extreme labiolingual compression, and large size observed in carcharodontosaurids such as Mapusaurus, Giganotosaurus, and Carcharodontosaurus (Coria & Currie, 2006;Novas et al., 2013). It shares a rectilinear, moderately recurved shape and non-angled, rectangular ('cartouche') distal denticles with Acrocanthosaurus, but differs in its smaller size, narrower base, and presence of interdenticular sulci, transverse enamel banding, and apically-restricted mesial carina (Currie & Carpenter, 2000;Harris, 1998). ...
... The incomplete manual ungual (DMNH 2013-07-0494) is assigned to the Allosauroidea due to possessing the following characters: an oval-shaped articular facet, pendulous flexor tubercle with a dorsal constriction, and mediolateral compression (proximal height:width ratio of 2.32) (Benson, Carrano & Brusatte, 2010;Rauhut, 2003). DMNH 2013-07-0494 is similar to the unguals of carcharodontosaurids Mapusaurus and Concavenator, but differs markedly from the unguals of Acrocanthosaurus, which are proportionally smaller and less curved with a small, rounded flexor tubercle most likely related to specialized function of the forelimb during predation (Coria & Currie, 2006;Currie & Carpenter, 2000;Ortega, Escaso & Sanz, 2010;Senter & Robins, 2005). DMNH 2013-07-0494 shares similar dimensions to ungual II-3 of Allosaurus, yielding a length estimate of 7-8 m for this individual (Madsen, 1976). ...
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... Judging from the angle of the maxillary tooth in the first alveolus, the contact surface for the premaxilla at the anterior margin of the maxilla is presumably subvertical as in Allosaurus [29], Neovenator [27] and Yangchuanosaurus [30]. This condition differs from the posterodorsally inclined margin of Carcharodontosauridae [5,26,27,[31][32][33][34] and Sinraptor [7,35]. ...
... The lateral surface of the maxilla has a rugose texture as reported in many members of Carcharodontosauria [27,32,34,36]. Additional surface texturing of the maxilla consists of at least six dorsoventrally extending ridges that are situated between the second and seventh alveoli (figure 2a). ...
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Carcharodontosauria is a group of medium to large-sized predatory theropods, distributed worldwide during the Cretaceous. These theropods were probably the apex predators of Asiamerica in the early Late Cretaceous prior to the ascent of tyrannosaurids, although few Laurasian species are known from this time due to a poor rock record. Here, we describe Ulughbegsaurus uzbekistanensis gen. et sp. nov. from the early Late Cretaceous (Turonian) of Central Asia, which represents the first record of a Late Cretaceous carcharodontosaurian from the region. This new taxon is represented by a large, isolated maxilla from the Bissekty Formation of the Kyzylkum Desert, the Republic of Uzbekistan, a formation yielding a rich and diverse assemblage of dinosaurs and other vertebrates from fragmentary remains. Comparison of the maxilla with that of other allosauroids indicates Ulughbegsaurus was 7.5–8 m in body length and greater than 1000 kg in body mass, suggesting it was the previously unrecognized apex predator of the Bissekty ecosystem while smaller known tryannosauroids and dromaeosaurids were probable mesopredators. The discovery of Ulughbegsaurus records the geologically latest stratigraphic co-occurrence of carcharodontosaurid and tyrannosauroid dinosaurs from Laurasia, and evidence indicates carcharodontosaurians remained the dominant predators relative to tyrannosauroids, at least in Asia, as late as the Turonian.
... The phalanx IV-1 of Abelisauridae indet. MPCN-PV-69 also differs from that of Sinraptor (Currie and Zhao, 1993), Mapusaurus (MCF-PVPH-108; Coria and Currie, 2006), and Tyrannosaurus (Brochu, 2003), in which this phalanx is stocky, lacks dorsal keels and have a hyperextensor pit that is more transversally developed and with a semicircular outline. Brusatte et al. (2008) mentioned for Neovenator an anteroposteriorly expanded oval hyperextensor pit on proximal phalanges, different from the obliquely oval fossa in Abelisauridae indet. ...
Article
Abelisauridae is a theropod clade with a wide distribution in the Late Cretaceous of Gondwana. Some of the best preserved abelisaurid specimens were recovered from Patagonia (Argentina) such as Skorpiovenator, Ilokelesia, Carnotaurus and Aucasaurus. Here we describe a dorsal part of a neural spine; a middle caudal vertebra; a distal part of a left metatarsal IV; a complete right phalanx IV-1; left phalanges IV-1, 2 and 3; and a pedal ungual phalanx. These materials were recovered from the same quarry of a recently published indeterminate abelisaurid specimen (MPCN-PV-69). The most distinctive characters are a triangular shape of the distal end of metatarsal IV (present in other abelisauroids); phalanx IV-1 with the proximal surface dorsoventrally tall and the ventral surface wider than the dorsal one causing a medial tilting of bone (set of features considered autapomorphic in Velocisaurus, although is also present in different abelisaurids); phalanx IV-1 and 2 with a ridge which spans from the proximodorsal projection, splits in two branch and surrounds a laterally displaced and obliquely oriented oval hyperextensor pit; a pedal ungual phalanx with two medial and lateral vascular grooves, and lacking a flexor tubercle (abelisauroids synapomorphies). The mentioned feature of phalanges IV-1 and 2 is only found among abelisaurids and is here considered as a possible new synapomorphy of Abelisauridae. Thus, besides they constitute new abelisaurid remains from Patagonia, the new materials provide valuable morphological data that could expand the diagnosis of Abelisauridae.
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Article
Although interactions between eolian and fluvial systems are well documented in both modern and ancient environments, there are few studies of such deposits that also address the paleosols that developed within them. The Cenomanian Candeleros and Huincul formations of the Neuqu´en Basin, Northern Patagonia, Argentina, provides an excellent opportunity to do so. These formations preserve mixed fluvial-eolian and fluvial systems, respectively, with associated pedogenesis. We identify five lithofacies associations (fluvial channel deposits [FA1], deposits of unconfined fluvial flows [FA2], floodplain deposits [FA3], eolian-dune deposits [FA4], and wet interdune deposits [FA5]), and five pedotypes (calcic Protosols [P1], Vertisols [P2], vertic and gleyed Protosols [P3a and P3b, respectively], vertic Calcisols [P4], and argillic Protosols [P5]). The lower Candeleros Formation is characterized by eolian dune deposits with calcic Protosols and wet interdune deposits with Vertisols and vertic and gleyed Protosols. The middle part of the formation is dominated by deposits of unconfined fluvial flows with vertic Protosols and, in the upper part of the unit, there are channel deposits with vertic Calcisols. The Huincul Formation is characterized by fluvial deposits with argillic Protosols. Changes in paleosol development have been recorded throughout the two formations. Small-scale changes, recognized in the lower Candeleros Formation, comprise a chrono-toposequence, in which calcic Protosols, Vertisols, vertic and gleyed Protosols are genetically associated with FA4 and FA5. Calcic Protosols developed on the dunes and gleyed Protosols in the inner part of the interdunes subjected to temporal waterlogging. When the dunes were vegetated and pedogenesis promoted dune fixation, the rate of dune mobility was slow and the ancient soils developed into Vertisols. In turn, the absence of vegetation was linked to a relatively high rate of dune migration, the time of soil development was limited, and, as a result, vertic Protosols were preserved. The analysis of soil-forming factors as large-scale controlling factors showed that throughout the succession, variations on the type of paleosol and the sedimentary environment over time were controlled by changes in ancient climate. Mid-Cretaceous global climate reconstructions suggest that the paleosols developed in northern Patagonia were located near the limit between the Southern Mid-latitude Warm Humid Belt and the Southern Hot Arid Belt. Seasonally arid and semi-arid conditions prevailed in this area, although there was a temporal trend towards a temperate subhumid climate.
... Monodominant large theropod dinosaur bonebeds are rare in the geologic record. Published examples include the Lower Jurassic Dilophosaurus wetherilli type locality (Welles, 1954), the Upper Jurassic Cleveland-Lloyd Allosaurus fragilis-dominated site in central Utah (Madsen, 1976;Gates, 2005;Peterson et al., 2017), the middle Cretaceous Mapusaurus locality in Neuquen, Argentina (Coria & Currie, 2006), the Upper Cretaceous MAD05-42 Majungasaurus quarry in Madagascar (Ratsimbaholison, Felice & O'Connor, 2016), the middle Cretaceous tyrannosauroid Yutyrannus site in China (Xu et al., 2012), and two tyrannosaurid sites from North America (Fig. 1): the Dry Island Buffalo Jump Albertosaurus sarcophagus site in the lower Maastrichtian Horseshoe Canyon Formation of Alberta, Canada , and the Daspletosaurus horneri site (TA 1997.002) in the upper Campanian portion of the Two Medicine Formation of central Montana (Currie et al., 2005;Carr et al., 2017). Previous analyses of the two North American tyrannosaurid sites concluded they both possibly represent mass mortality of an aggregation and are not time-averaged or catastrophicallyforced (Currie, 1998;. ...
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Tyrannosaurids are hypothesized to be gregarious, possibly parasocial carnivores engaging in cooperative hunting and extended parental care. A tyrannosaurid (cf. Teratophoneus curriei ) bonebed in the late Campanian age Kaiparowits Formation of southern Utah, nicknamed the Rainbows and Unicorns Quarry (RUQ), provides the first opportunity to investigate possible tyrannosaurid gregariousness in a taxon unique to southern Laramidia. Analyses of the site’s sedimentology, fauna, flora, stable isotopes, rare earth elements (REE), charcoal content and taphonomy suggest a complex history starting with the deaths and transport of tyrannosaurids into a peri-fluvial, low-energy lacustrine setting. Isotopic and REE analyses of the fossil material yields a relatively homogeneous signature indicating the assemblage was derived from the same source and represents a fauna living in a single ecospace. Subsequent drying of the lake and fluctuating water tables simultaneously overprinted the bones with pedogenic carbonate and structurally weakened them through wet-dry cycling. Abundant charcoal recovered from the primary bone layer indicate a low temperature fire played a role in the site history, possibly triggering an avulsion that exhumed and reburied skeletal material on the margin of a new channel with minimal transport. Possible causes of mortality and concentration of the tyrannosaurids include cyanobacterial toxicosis, fire, and flooding, the latter being the preferred hypothesis. Comparisons of the RUQ site with other North American tyrannosaur bonebeds (Dry Island-Alberta; Daspletosaurus horneri -Montana) suggest all formed through similar processes. Combined with ichnological evidence, these tyrannosaur mass-burial sites could be part of an emerging pattern throughout Laramidia reflecting innate tyrannosaurid behavior such as habitual gregariousness.
... Together, these laminae define the medial borders of angular, laterally shallowing depressions on the anterior surface of the neural arch, interpreted as centroprezygapophyseal fossae sensu Wilson et al. (2011;= peduncular fossae of Britt 1993). Centroprezygapophyseal fossae are present in anterior dorsal vertebrae of other non-maniraptoriform (i.e., allosauroid and early diverging coelurosaurian) avetheropods (e.g., the metriacanthosaurid Sinraptor dongi [Currie and Zhao 1993], carcharodontosaurids [Coria and Currie 2006;Canale et al. 2015]), including other megaraptorids, in which they are often better developed than in UNPSJB-PV 944; indeed, in dorsal vertebra 2 of Murusraptor, the centroprezygapophyseal fossae are floored by pneumatic foramina that invade the neural arch (Coria and Currie 2016). The lateral margins of the centroprezygapophyseal fossae are comprised by robust, gently anterodorsally inclined centroprezygapophyseal laminae. ...
... 17e), Siats (Zanno andMakovicky 2013: figs. 2b, d, f), and at least some metriacanthosaurids (Currie and Zhao 1993;Gao 1999), carcharodontosaurids (Coria and Currie 2006;Canale et al. 2015), and tyrannosauroids (Brochu 2003), there is no concrete evidence of a hyposphene or hypantrum. The transverse processes are oriented subhorizontally (only very slightly dorsolaterally), in sharp contrast to the condition in many other non-maniraptoriform avetheropods for which anterior dorsal vertebrae have been illustrated in anterior or posterior view (e.g., metriacanthosaurids, Murusraptor, tyrannosaurids); in these animals, the transverse processes are steeply dorsolaterally inclined. ...
... 63a, 64), and most other megaraptorids (Aerosteon, Australovenator, Megaraptor, Murusraptor, Tratayenia), though in most of these taxa the foramina are larger and better developed. Other avetheropods (e.g., the metriacanthosaurid Sinraptor dongi [Currie and Zhao 1993] and the carcharodontosaurid Mapusaurus roseae [Coria and Currie 2006]) have been described as having pneumatic foramina penetrating the posterior rather than the anterior surfaces of some dorsal rib heads, whereas Murusraptor has pneumatopores invading both of these surfaces (Coria and Currie 2016). No potentially pneumatic features were reported in the fragmentary dorsal ribs of the indeterminate Australian megaraptorid LRF 100-106 (Bell et al. 2016), the early diverging megaraptoran Fukuiraptor (Azuma and Currie 2000), or the putative megaraptoran Vayuraptor nongbualamphuensis (Samathi et al. 2019), though it is not completely clear that the ribs attributed to Fukuiraptor do in fact pertain to this taxon. ...
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We describe two partial postcranial skeletons belonging to the enigmatic theropod dinosaur clade Megaraptoridae from the Upper Cretaceous (lower Cenomanian-upper Turonian) Bajo Barreal Formation of southern Chubut Province, central Patagonia, Argentina. The specimens are assigned to Megaraptoridae due to their possession of multiple anatomical features that are considered synapomorphies of that predatory dinosaur group, such as a greatly enlarged, laterally compressed ungual of manual digit I that possesses asymmetrical lateral and medial vascular grooves. Overlapping elements of the two skeletons are nearly identical in morphology, suggesting that they probably represent the same taxon, a large-bodied theropod that was previously unknown from the early Late Cretaceous of southern South America. The Bajo Barreal specimens constitute the most ancient unquestionable records of Megaraptoridae from that continent, and exhibit particularly strong osteological resemblances to penecontemporaneous megaraptorids from the Winton Formation of Australia. Phylogenetic analysis recovers the unnamed Bajo Barreal taxon as the earliest-diverging South American megaraptorid and the oldest-known representative of this clade that likely attained a body length of at least seven meters and a mass of at least one metric ton. Overall, the balance of the evidence suggests that megaraptorids originated in eastern Gondwana (Australia) during the Early Cretaceous, then subsequently dispersed to western Gondwana (South America) during the mid-Cretaceous, where they attained substantially larger body sizes, ultimately coming to occupy the apex predator niches in their respective habitats.