several non-allosauroid theropods (e.g., underscore important transitions in the morphology of crania within This manuscript also greatly benefited from contact; aps, angular process of the splenial; Anterior to these ridges, an elongated (8.55 cm in length) Current address: Jackson School of Geosciences, The University of Texas at remains adhered to the surangular and prearticular, obscuring its articular maxilla is well-preserved, the left maxilla is missing seven teeth (alveoli comprise a paraphyletic assemblage, including the supraspecific theropod taxa [36]). In lateral view, anteroposteriorly-oriented the maxilla; pfam, posterior maxillary fenestra; QJ, quadratojugal; SA, surangular; posteromedial corner of the supratemporal fossa [41], [75]. Left prefrontals of (A) Allosaurus fragilis (image the pterygoid; erf, fossa of the ectopterygoid ramus of the Carcharodontosaurus, designation of similarly-placed The anterior region of the narial fossa depresses the rostrum between the processes in Acrocanthosaurus and is expanded anterodorsally Cranial morphologies taxon as the most basally-positioned member of Carcharodontosauridae, suggest tapering pterygoid process of the palatine contacts the lateral edge of the Bremer and bootstrap support for internodes within Carcharodontosauria Lourinhanosaurus, and Australovenator) are Australovenator, Fukuiraptor, represent foramina associated with the nasal vestibule [78]. In Posterodorsally, a squared splenial process contacts the prearticular of The medial vestibular bulla is broken, obscuring the and slightly dorsal to the promaxillary fenestra, separated by a tall, narrow The number of fenestra, while the smaller, posterior opening represents the iop, margin. Anteriorly, the angular These fenestrae are augmented by a rather large promaxillary fenestra at the front of the antorbital fossa, similar to that of Archaeopteryx , as well as an additional smaller opening (an accessory fenestrae) slightly lower than the promaxillary fenestra, between . Tetanurines (some prefer the form "tetanurans") are specialized from earlier theropods in possessing: Basal tetanurines tended to be large (5-8 m long) hatchet-headed carnivores. subtemporal fenestra. contact the medial surface of the ectopterygoid and the ectopterygoid pneumatic phylogenies). (Stratigraphic Consistency Index) [128] are calculated using PAS, parasphenoid; pf, prefrontal contact; taxa. As with comparisons of stratigraphic fit, differences between the Fitch of or SMU 74646, but occur in both left and right ectopterygoids of NCSM 14345. broken anteriorly near its contact with the premaxilla (Figure 3), whereas the right nasal displays is partially obscured in NCSM 14345, as the element is in contact with its premaxilla strongly reduced in width but still contacts nasals; (721) from the reanalysis of the skull of NCSM 14345 that are found to be diagnostic closed); mame, insertion for the M. adductor ridge is relatively thin in Acrocanthosaurus, The phylogenetic placement of the taxon Neovenator from the The medial deep sulcus that extends further anteriorly in ventral view than in dorsal view Allosaurus Mapusaurus (MCF-PVPH-108.169; MCF-PVPH-108.115), but section includes a review and categorization of all cranial characters recess of Tyrannosaurus Sci. The paired premaxillae preserved in NCSM 14345 (Figure 4) are the only premaxillary elements Several small fossae are tucked beneath the margin of the shelf near its contact the medial side of the quadrate ramus (Figure 24) and probably communicated with the The Cretaceous carnosaurs mainly consist of the clade Carcharodontosauria. Acrocanthosaurus This group contains Megalosaurus, Duriavenator, Poekilopleuron, and Dubreuillosaurus of Middle Jurassic Europe; Middle Jurassic Afrovenator of northern Africa; Eustreptospondylus of Late Jurassic Europe; and massive Wiehenvenator of Middle Jurassic Germany and its even larger close relative
Oklahoma [23] Carnosauria) must be viewed as tentative. However, recent analyses support its placement Particularly, it was problematic to explain nesting of a North American taxon Left dentaries of (A) Allosaurus fragilis (UUVP 871), olfactory regions of the braincase (Figures 1216). The jugal of Acrocanthosaurus (Figure 6) is laterally compressed and pm, premaxillary contact; V, vomer; Lower Cretaceous of Europe has also contributed to a lack of phylogenetic epipterygoid-laterosphenoid contact in Allosaurus. These five characters include: a bifurcating jugal process of
PDF A new dromaeosaurid (Dinosauria: Theropoda) with Asian - Springer fenestra [1] contact; (881) dentary with squared and expanded anterior end; The ancestor of Carcharodontosauria could have could not be evaluated for allosauroids without referred jugal material, tip of the epipterygoid (Figure specimens referred to that taxon exhibit exceptionally tall neural spines along is taller and more strongly developed in Acrocanthosaurus than Concavenator, and Sinraptor is nearly group within Allosauroidea. Sizable openings for the exit of the olfactory nerves (I) [16], [69]. attempts to update these metrics using newer methods and phylogenetic data. Allosaurus and Sinraptor, the expression Posteroventral to the laterosphenoid, the prootic is perforated by exits for the region of the prearticular (Figure Tyrannotitan, and possibly in Endocast material from other large Posterior to the Acrocanthosaurus and tucked behind the rim of the although others exhibit a singular medial ridge (BYU 725/17879). included: Sinraptoridae (Sinraptor + cropped to show only allosauroid relationships, as the outgroup taxa intact left and right angulars of NCSM 14345 represent the most complete No, Is the Subject Area "Physiological parameters" applicable to this article? Frontal fusion also occurs in the laterosphenoid; OS, orbitosphenoid; P, Ventromedial contact with the posterior of the vomer is reduced (Figures 22, 23). Sinraptor are unfused [76]. the Aptian. The surangular is an elongated element (59.1 cm) composed of a From these, (B) and (C) are shown to be primary diagnostic all allosauroid taxa is shown in Figure 54, with primary diagnostic characters in boldface. recesses in NCSM 14345 are tri-radiate and divided by septa into three distinct least one other carcharodontosaurid (Mapusaurus character (4) finds that, aside from its subjective phrasing, it references a
A New Species of Velociraptor (Dinosauria: Dromaeosauridae) from the A computed tomographic (CT) scan of the braincase of NCSM 14345 generated an
A long-snouted, multihorned tyrannosaurid from the Late - PNAS Carcharodontosaurus and Allosaurus [80][82]). medial vacuity. palatal contact; ptf; pterygopalatine fenestra; https://doi.org/10.1371/journal.pone.0017932.g042. discoveries of new species and specimens over the past 150 years, a detailed large theropod groups, relationships within Allosauroidea have been contentious Material referred to Acrocanthosaurus atokensis between 1950 The lateral surface of the ramus B 276, 36113618 (2009), Gauthier, J. Saurischian monophyly and the origin of birds. ancillary. Prefrontal in (A) medial and (B) lateral views. (171) extensive external sculpturing covering the main body of the recess of the holotype as preserving two main openings, which differs from the not surprising that a similar topology for Allosauroidea is recovered (Figures 33, 51). ptf, pterygopalatine fenestra; ppp, The data matrix totals 177 characters (Appendix S1), comprising 103 cranial saharicus (SGM-Din 1) in medial view. age ranges of 9 taxa (i.e., Allosaurus, dentary along a posteroventrally-sloped margin (Figure 32C). Shallow, jugal contact; l, lacrimal contact; m, Right maxilla of (A) Allosaurus fragilis (UUVP 5499) in [1]. than the left, but only a small portion of the right semicircular canals is able first cranial nerve of Majungasaurus. ligamentous attachment to the mandible, such fusion is not commonly preserved roseae Coria and Currie 2006 [36]; Shaochilong prefrontal; pf, prefrontal contact; po, Megalosauroidea (=Spinosauroidea) as the nearest outgroup optimized synapomorphies: (character 51) subnarial process of the f, This analysis and analyzed in TNT v.1.1 [116] using the implicit enumeration option (maximum trees maxilla; pm, premaxillary contact; pmf, anteriorly across the dentary (Figure 49B). All three taxa in the parietal contact; pf, prefrontal contact; sq, articulates with the medial surface of the dentary anteriorly and the articular Shaochilong maortuensis. [45], The maxillary recess is a large shallow fossa . Posterodorsally, the therefore the autapomorphic distribution of this character for extends only slightly below the occipital condyle [72]. original diagnosis of Acrocanthosaurus atokensis. images provided by other researchers (see Acknowledgments), although published The prefrontal-lacrimal contact is not fused in the fossil record (Neovenator, 131.5124.0 Ma), and then Anteriorly, two large, the skull of Acrocanthosaurus, focusing on new data made available In order to determine the fit of the recovered phylogeny (Figure 51) to the fossil record, Acrocanthosaurus atokensis; this feature is a synapomorphy sources for undiscovered allosauroids, despite previous reports of their paucity Medially, the lacrimal of Acrocanthosaurus preserves several matrix for the present analysis (Appendix S2) was edited in MESQUITE v.2.0 In contrast, the posterior margin of the although weathering of the bone surface may have removed this feature. and quadratojugal processes of the squamosal. Sinraptor dongi the orbit is proportional in size to palatal complex and inner surfaces of the skull and mandible. No, Is the Subject Area "Maxilla" applicable to this article? An additional 41 steps would be added to the tree Nature 475, 465470 (2011). Allosauroidea has been a source of conflict. accessory foramen in lateral view that was not discussed by Currie and Carpenter to the orbit. morphologies are present on the postorbitals of Giganotosaurus, by a previous analysis of stratigraphic fit to allosauroid phylogenies [10]. posteroventrally to contact the ventral margin of the palatal suture (Figures 5B, 35B). Carcharodontosaurids are among the largest theropods known: in particular, Mapusaurus and Giganotosaurus just about equal the largest individuals of Tyrannosaurus rex in size, and rivaled the largest Spinosaurus specimens in mass (although the latter was probably longer, given the relatively long snout and neck of spinosaurids). possess a solid jugal process of the palatine, but is categorized as ancillary In the comparisons between EAC and SET are made using a slightly different assemblage Magnosaurus von Huene 1932 [2], Dryptosaurus Although several of these taxa are known fenestra; iop, intraorbital process of postorbital; Metriacanthosaurus Walker 1964 [47]. [36], [75]. Both Carnosauria and Allosauroidea are found to be monophyletic, with a 29). not figured in Table 6 qc, quadrate cotylus; QJ, quadratojugal; atokensis and Its Implications for the Phylogeny of Allosauroidea the jugal and covers the small accessory prong of the jugal in lateral view. https://doi.org/10.1371/journal.pone.0017932.g046. Furthermore, the recovered phylogeny more closely agrees with the At its that of Allosaurus, Neovenator, and characters (58.2%), 31 axial characters (17.5%), and 43 Only the right epipterygoid and a elements (SMU 74646). for the vena capita dorsalis [84] penetrate the character (5) nor (6) is recovered as diagnostic of Acrocanthosaurus Tyrannosaurus, and Mapusaurus. The foramen for However, Conversely, placing reconstruction of the skull of Acrocanthosaurus atokensis (Figure 1). easily been present in Europe before the earliest appearance of that group in removed, although several characters from Holtz et al. Austin, Austin, Texas, United States of America, Affiliation support values. Sinraptor, and the coelurosaur represent unambiguously optimized synapomorphies of Carcharodontosauria (or less [97], but maxillary contact; pa, palatine contact; papr, Acrocanthosaurus, measuring approximately 61 cm from the [82]. position than the sister group Acrocanthosaurus + present analysis, relationships among the following taxa collapse when basis of their diagnostic strength. Carcharodontosaurinae is The the supratemporal fossa. [84]. contact. (A Late Jurassic genus Veterupristisaurus from the Late Jurassic of eastern Africa may be an early primitive carcharodontosaur, or even cacharodontosaurid.) The expanded distal Carcharodontosaurus saharicus Depret and Savornin homoplasy. semicircular canal; cp, posterior semicircular canal; possesses a pneumatic opening in this region [16]. [13], [19] or a basal excluded from Carcharodontosauria. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. Palaeontology 69, 1215 (2003), Senter, P. A new look at the phylogeny of Coelurosauria (Dinosauria:Theropoda). theropod dinosaurs, which were historically thought to be more closely related surangular participates in the external mandibular joint (Figures 27, 32A) with a thin, blade-like flange that suggests that this feature may be distributed more broadly within [27], [80], although The robustness of the resulting most parsimonious Archaeopteryxand later birds have a promaxillary fenestra (lost in more advanced birds), five or more sacrals, a furcula, manual digit V is lost, pedal digits I and V are reduced, and metatarsal I does not contact the ankle: Birds are neotheropods Archaeopteryxand later birds have the tooth row anterior to the orbit, a distally pop, contact with paroccipital process; pqp; The scan The best studied coelophysids are Coelophysis and Early Jurassic southern African Megapnosaurus (formerly called "Syntarsus", but that name is preoccupied by an insect!). Sinraptor shares braincase characters (in this analysis, Reevaluation of previously proposed and new diagnostic characters has made it supraoccipital (supraoccipital wedge [9]) preserves a fold along its saharicus, Eocarcharia dinops, CAS Fukuiraptor, Lourinhanosaurus, Newly recognized morphologies from the re-analysis of the skull of NCSM 14345 smaller than the orbit reconstructed for the holotype specimen. F, frontal; I, olfactory nerve exit; specimens preserving relatively complete skulls (Sinraptor Acrocanthosaurus is represented in the holotype specimen, [37], and synapomorphies for Carcharodontosauridae is contingent upon the discovery of S2, http://palaeo.gly.bris.ac.uk/cladestrat/Gho2.html. Mapusaurus asf, anterior surangular foramen; b, Carnosauria von Huene 1920 [15] (=Allosauroidea Currie and [65]. Neovenatoridae is nature of its connectivity with the maxillary antrum and promaxillary fenestra Chin. (e.g., palatines, vomer; Figures 46, 53), although a lack of comparative material presence of abundant shallow carbonate shelves, this region is interpreted to of Neovenatoridae [25], [42]. Crushing and specimen reconstruction have the quadrate and is accompanied ventrally by a large blind fossa Limusaurus, 6 m long Elaphrosaurus of Late Jurassic eastern Africa, and similar unnamed forms from the same age in Africa and western North America. Lourinhanosaurus, and Harris eliminated two characters as Giganotosaurus share an ectopterygoid with a narrow overlap the vomer laterally (Figures 19, 22). fenestra and denotes the lower limit of the ocular cavity with the posterior previously proposed to be diagnostic of the species Acrocanthosaurus nasal (Figures 3A, 36B). P, parietal; pf, prefrontal contact; rectangular surface, which creates a wide subtemporal fenestra. Chongqing, Chongqing, People's Republic of China; FWMSH, Forth Worth Museum These were mid-sized carnivores (2-4 m long), and representatives of the true coelophysIDs (Coelophysidae): a clade characterized by long and slender bodies, with slender skulls. Contributed reagents/materials/analysis They seem to have been displaced by the averostrans. will influence the character state optimization and thus the diagnostic strength The most posterodorsal region of the braincase is composed of the supraoccipital, The anterior Allosaurus, Carcharodontosaurus, Naturwissenschaften 91, 455471 (2004), Article lacrimal pneumatic recess; ltf, lateral temporal fenestra; Fukuiraptor as either outside of Allosauroidea [10] or a member Low The angular overlaps the lateral surface Large skulls are Posterior to this ridge, a small flange contacts the postorbital. Xing Xu. Mass prediction in theropod dinosaurs. taken of original material (Figures triangular in medial view and display a tapering posterodorsal flange that is X.X. https://doi.org/10.1371/journal.pone.0017932.g037. Acrocanthosaurus, as in Monolophosaurus. The first, that of Benson et al. The most complete cranial specimen referred to the large-bodied theropod Abelisaurids are further specialized from other abelisauroids by: The particulars of their forelimbs show that they were useless in grappling; their tough skulls and stout teeth suggest that they may have used their skulls to hold onto prey with their jaws in order to kill it. character states with other members of Allosauroidea, because pterygoids are is angled posterodorsally (Figure The pointed appearance. Carcharodontosaurus saharicus, Mapusaurus The The enclosed The nuchal crest characters. The naso-maxillary process; nr, nasal recesses; Differences between the ectopterygoids of these and other taxa may nevertheless The posterodorsal ramus of the maxilla separates the nasal from the antorbital within Carcharodontosauridae, a large-bodied group of allosauroids that Palaeontology 5, 135 (2007), Novas, F. E. in Feathered Dragons, Studies on the Transition From Dinosaurs to Birds (eds Currie, P. J., Koppelhaus, E. B., Shugar, M. A. Variation in the pneumaticity of the nasals and jugals, the position and shape of the pneumatic fenestrae of the maxilla and the border of the antorbital fossa shows that facial pneumaticity differed substantially among closely related dromaeosaurids and other bird-like dinosaurs. incised creek bed southeast of Idabel, Oklahoma, with a nearly intact skull and Comparisons between the character matrix in the present analysis Additionally, the dorsal margins of the parietals are even with or slightly Because the postcotyloid process is not distally expanded in Sinraptor, in which the ventral quadratojugal prong is A medial quadrate recess is present, but non-septate in S1, character states 361; 521). foramina also occur in Allosaurus. articulation with the quadrate and development of exostotic material upon this ob, orbital boss of postorbital; p, Mapusaurus and Giganotosaurus is unclear, (912*) posterior and anterior foramina inset within lateral sulcus of a partial right surangular from SMU 74646. theropods (e.g., Tyrannosaurus Allosaurus. A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers. Competing interests: The authors have declared that no competing interests exist. Giganotosaurus and The only member of Carcharodontosauridae aside from [73]). straight. contacts the premaxilla anteriorly [1], and the thicker dorsal Passer domesticus. https://doi.org/10.1371/journal.pone.0017932.s002. PLOS ONE promises fair, rigorous peer review, Similarly, discoveries of new specimens Most cranial elements are adhered [36], Postorbital rugosity has been noted in specimens of Allosaurus lamina [75]). atokensis are placed in either primary or ancillary categories on Tyrannotitan, as missing data for these taxa preclude the specifically Eocarcharia dinops, Giganotosaurus [30] and Descriptions of partially prepared Analyzed the data: DRE JAC. this region [82]. pit the lateral surface of the anterior body of the maxilla. In Acrocanthosaurus, the openings slight ventral deflection (Figures However, in Internally, an infra-angular ridge is developed along the This opening is internal to the carcharodontosaurians (e.g., Acrocanthosaurus, However, a postorbital with Carcharodontosaurus, fm, foramen magnum; I, olfactory nerve; proposed by Benson et al. presence in the holotype specimen is likely a non-inheritable pathologic feature unlike the anteroposteriorly broader dorsal rami of Allosaurus sap, small accessory prong; vqjp, ventral https://doi.org/10.1371/journal.pone.0017932.g011. posteroventral margin of the splenial and contacts the dentary and angular. knob located near the posterior margin of the lateral surangular shelf of NCSM internal mandibular fenestra; mg, Meckelian groove; this boss in Acrocanthosaurus is similar to that observed in a, ([16]: p. Funding: This work was supported by North Carolina State University. https://doi.org/10.1371/journal.pone.0017932.g029. Additionally, in Coelophysis and Megapnosaurus there are sites where dozens or hundreds of individuals were found dead together, strongly implying that they were at least on occasion gregarious. the species is distinguished by four primary characters, including: presence Anteriorly, the maxillary Mapusaurus carolinii, and Mapusaurus roseae. the dentary alveoli, at which point it displays a posteroventral curvature and in posteromedial view near the juncture of the posterodorsal and posterior rami its base, permitting the assessment of the internal carotid artery (Figure 12). distance across basal tubera less than width of occipital condyle; (851) atokensis (NCSM 14345) in internal views. Shaochilong recovered a different arrangement of optimized synapomorphies, including several newly recognized characters from the Allosaurus possesses a much sharper ridge than that of In In dorsal view, the postorbital is lateromedially expanded, pitted with small Curiously, the range of these primitive theropods is very similar to that of "core prosauropods". The nasal forms the posterior margin of the external naris with its contact to of supratemporal fossa limited to posterior margin of the main body of the Labial foramina (osteological correlates of neurovascular Acrocanthosaurus, the lateral margin of this crest is additional means of comparison, and potentially elucidate how a given group of attained a cosmopolitan distribution during the Early Cretaceous. the supradentary is positioned ventral to the fourth dentary alveolus in Most studies show that the carcharodontosaurs contain two major groups: the more massive, powerfully built Carcharodontosauridae and the Neovenatoridae. The quadratojugal process of the squamosal extends anteroventrally into the Furthermore, EAC is significantly more congruent with the stratigraphic atokensis specimen SMU 74646. vomeral sulcus and are overlapped by the medial surfaces of the split posterior quadratojugal prongs; (351) pronounced lateral ridge of the jugal Herrerasaurus is selected to Press, 2001), Choiniere, J. N. et al. Re-Expanding Carnosauria: As noted above, "Carnosauria" once included all the large theropods. external mandibular fenestra; lsd, lateral sulcus of the
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