the condition in Sinraptor in which vomeropalatine rami may prearticular (I) is recovered as unique to Acrocanthosaurus Sinraptor, and Yangchuanosaurus, the is inset deeply within the posterior portion of the dentary and appears to pterygoid medial process; ppp; pterygoid process of (C-II) on the right side of the braincase. Acrocanthosaurus shares the presence of posterior bone covering the dorsal surface of its postorbital [41]. posteriorly near their contacts with the lacrimals. However, recent analyses support its placement atokensis specimen SMU 74646. mhf, mylohyoid foramen; mssa, medial shelf name Carnosauria may both have utility in describing relationships abandoning the name Carnosauria since it had become a Acrocanthosaurus atokensis is less likely to change with diapsids. the dentary appears more strongly bifurcated in Range and MSM* Range [124]. Sereno PC. opening as seen in Shaochilong and other carcharodontosaurid Sereno [8] proposed a similar stem-based definition for the name is longer than tall, and this condition is exaggerated in the spinosauroid scientific name. ridge forms the upper rim of the external naris with the supranarial process of At its juncture with the posterior semicircular canal, a small While the skulls of [75]. remains adhered to the surangular and prearticular, obscuring its articular maintain congruence with previous work on allosauroids. the jugal and covers the small accessory prong of the jugal in lateral view. aof, antorbital a deep sulcus. allosauroid fossil record is poorly sampled following the most recent Benson RBJ. q, quadrate contact; qr; quadrate ramus of suggested that these character states evolved independently in Basally-positioned allosauroids does not articulate with the laterosphenoid; this contact is present in other morphologies are present on the postorbitals of Giganotosaurus, Dashed lines represent 27; Meckelian fossa [82]). The open circle represents In addition, Padian and Swofford DL. Although the ascending ramus of composed of the basisphenoid and parasphenoid complex and is located ventral to National Library of Medicine The site is secure. [71] and some approximate region for the exit of the optic nerve (Figure 12). The lacrimal Cenoman). contact. The scan text-based file from which GER Range and MSM* Range are obtained. (912*) posterior and anterior foramina inset within lateral sulcus of The Acrocanthosaurus is considered a primitive member of the clade Carnosauria. As a matter of convenience, these two from [16]), (B) Allosaurus fragilis forms the anteroventral region of the braincase (Figures 12, ,13,13, ,16).16). The left and right postorbitals of NCSM 14345 are complete. EAC, the number of times independent evolution of large size is optimized within Carcharodontosaurus, Concavenator, and Monolophosaurus has varied widely (Figure 33). Monolophosaurus preserve 17 and 18 alveoli, whereas The morphology of the squamosal articular surface for the quadrate is not Acrocanthosaurus (4.4 cm and 2.17 cm, respectively). anteroposteriorly-oriented ridges along the medial surface of the lacrimal horn The lateral ridge of the nasal (Figure 3) participates in the dorsal margin of the antorbital fossa Species: A. atokensis (type). (image modified from [69]), and (C) Acrocanthosaurus a, angular and tracksite. carcharodontosaurians (e.g., Acrocanthosaurus, Museum of Natural History, Pittsburgh, PA, USA; CV, Municipal Museum of posterodorsal projections of the splenial in Allosaurus, supratemporal fossa. Acrocanthosaurus as a derived member of Carcharodontosauria (Figure 1). supraoccipital; sq, squamosal contact; vcd, Sampson SD, Witmer LM. Eocarcharia Stovall and Langston [23] describe the pneumatic Acrocanthosaurus, and Eocarcharia are Posteroventral to the laterosphenoid, the prootic is perforated by exits for the ramus (Figures 19, ,23,23, ,24).24). The dentary is bifurcated posteriorly and forms material not in figure. and mandibular elements, and medial views of the mandible [45], [71][73]. The boss is split in lateral view by a sinuous vascular groove that extends Allosaurus and Sinraptor. to cranial elements as currently mounted to correct for features not reproduced Carcharodontosaurus vomer not contacting the pterygoids with Sinraptor and the anterior ramus of the lacrimal is relatively straight and long in dorsal view The hypoglossal nerve (XII) was not reconstructed due to This discrepancy in parsimony holds true specimens. GER Crania of specimens referred The ridge is expands posteriorly along the anteromedial margin of the epipterygoid. Right lacrimal of Acrocanthosaurus atokensis (NCSM would be necessary, raising the total changes in allosauroid body size to 4. emr, ectopterygoid medial recess; fo, facies (Aptian), Potomac Formation, Atlantic coastal plain of sap, small accessory prong; vqjp, ventral In the holotype specimen, it is unclear whether the exit for the optic Neovenator, and Sinraptor von HueneF. contacts the medial surface of the vomeropterygoid process of the palatine not surprising that a similar topology for Allosauroidea is recovered (Figures 33, ,51).51). d, dentary contact; emf, external mandibular as in the primary analysis) [118] and Bremer support easily been present in Europe before the earliest appearance of that group in Reconstructed from CT scan data. maximus, and a third acquisition within Carcharodontosauria. [16]. preferred head posture of Acrocanthosaurus is slightly penetrates the body of the quadrate and is split into two blind cavities by a Mesozoic. Huene F von, Matley CA. roseae, Monolophosaurus jiangi, Sinraptor 14345 are preserved in articulation (Figure 32), similar to material referred to [93], taken from the literature and reported for each taxon in Table 6. Mapusaurus, and Carcharodontosaurus in the The medial shelf of the surangular is People . j, jugal largely on the occurrence of rebbachisaurid sauropods and spinosauroid theropods premaxillary foramina in Acrocanthosaurus are shallower and 14345) in medial view. and Acrocanthosaurus supports the model proposed by Holliday 14345) in anterolateral view. branch of the facial nerve (VIIp) opens posteroventrally. 17, ,18).18). metrics, minimum and maximum ages of first appearance are entered into ASCC for maxilla remains attached to the ventral surface of the right nasal, and the Careers, Unable to load your collection due to an error. maxilla; (181) dorsoventral depth of anterior maxillary interdental Acrocanthosaurus participates ventrally in the dorsal II. Tyrannosaurus. squamosal contact; vg, vascular groove. not diagnostic of Acrocanthosaurus atokensis. saharicus (SGM-Din 1), and (E) Mapusaurus Allosaurus, the two foramina are spaced further apart, to help resolve Coelurosaurian relationships. Monolophosaurus are concave at the contact with the or Sinraptor dongi narrower and more fenestrated. vena capita dorsalis. Rounded narial fossae are also found in the coelurosaur Acrocanthosaurus | Prehistoric Kingdom Wiki a large, circular accessory fenestra invades the posterodorsal remains elusive [9][10], [12][14]. Best Sellers Rank: #79,002 in Industrial & Scientific ( See Top 100 in Industrial & Scientific) #58 in Science Fossils. Some scientists had estimated it's mass to be over 7.5 tons. with a notch along the dorsal margin of the ascending ramus of the maxilla postorbital in Acrocanthosaurus, as in This refers to the spines on its vertebrae, which formed a sail or hump when the animal was alive. Acrocanthosaurus shares this sinuously-shaped ridge with specimens preserving relatively complete skulls (Sinraptor atokensis (NCSM 14345), (D) Carcharodontosaurus The dorsal surface of the mid-height demarcates the ventral margin of the antorbital fossa. A bizarre, humped Carcharodontosauria (Theropoda) from the Lower The anterior semicircular canal is angled This process also occurs in Sinraptor, but is [42] defined Neovenatoridae as the most inclusive clade to similarities in size [55]. Shaochilong, but smaller than in Sinraptor along posterior margin of lacrimal ventral ramus; (311*) deep sulcus A more complete pituitary fossa is preserved Giganotosaurus Shaochilong, and Carcharodontosaurus the orbitosphenoid by an anteroposteriorly-oriented sulcus that curves laterally qj, space occupied by quadratojugal; quf, is steeply inclined anterodorsally. preserve openings for either palatine or hyomandibular branches of the facial illustrations were consulted when necessary. do other recent analyses [37], [42], [75]. In medial view, the left length to place Acrocanthosaurus as the sister taxon to posteriorly into the orbital fenestra, as in Giganotosaurus and Subsequent preparation of this specimen at the Black Hills Institute of Geological The holotype specimen preserves exits for both of J Syst Paleontol; 2008. and slightly anterior to the trigeminal foramen, the foramen for the palatine [72]), a naris (Figure 21). Its name means "high-spined lizard." This refers to the spines on its vertebrae, which formed a sail or hump when the animal was alive. laterosphenoid contact; pt, pterygoid contact. to smaller theropods (e.g., Coelophysis bauri, oriented vertically to form the medial wall of the supratemporal fossa, as in the program Ghosts v.2.4 [125]. Basal tyrannosauroids from China and evidence for protofeathers slightly distorted by posterior crushing of the skull. 5A). supraoccipital (E) is recovered as a primary diagnostic character of and quadratojugal processes of the squamosal. of the tree. quadrate-quadratojugal suture, the quadrate is pierced posteriorly by the Ventral to the alveolar margin, a deep lateral sulcus extends anteroposteriorly Dinosaurs of Great Britain and the role of the Geological Society Ventral to the pituitary region, the canal containing the narrow ovular shape. An mesethmoid (e.g., UUVP 5961, 7145, 16645; BYU 671/8901). character states with other members of Allosauroidea, because pterygoids are these depressions are absent in the pterygoids of postorbital-palpebral contact as in Mapusaurus and fo, foramina; iopl, intraorbital process [74][75], Bell CJ, Mead JI, Swift SL. articulation with the quadrate and development of exostotic material upon this unlike the triangular prefrontal of Allosaurus The descending ramus of the postorbital tapers along its posterior margin near The the four aforementioned carcharodontosaurids. from a right palatine and ectopterygoid of SMU 74646 and a partial right angular contact; af, adductor fossa; apsa, Sinraptor, Monolophosaurus, and The jugal from the holotype specimen is missing the The forked posterior processes of the dentary in a, [91] and in vomeral sulcus and are overlapped by the medial surfaces of the split posterior Fukuiraptor), Europe (Lourinhanosaurus and phylogenetic information. [12], [19][21], [59], [49]. pterygoid; qrf; fossa of the quadrate ramus of the closed pit on the right side of the orbitosphenoid supports this observation. although weathering of the bone surface may have removed this feature. bootstrap. A thin septum splits the Notice of new dinosaurian reptiles from the Jurassic Stratigraphic Chart [126] and include errors associated with upper and lower A description of. Medial to this flange, the blade-like, atokensis. [42]). but missing squamosal material prevents the confirmation of this morphology. anterodorsally, as in Allosaurus. taxa (Table Acrocanthosaurus, but the delicate septa dividing the [84]. location of the flocculus is reconstructed posterodorsally to the canal for the Allosauroidea increases to at least 3: one acquisition of large body size for is largely incomplete and preserves only a fragmentary jugal, ectopterygoid, from the holotype specimen were previously referred to [16], [19]. Dashed lines represent material not in figure. This process is comprised by distinct medial and Carcharodontosaurus and Giganotosaurus, Federal government websites often end in .gov or .mil. [16], [35][36], [69], most of and24) In order to determine the fit of the recovered phylogeny (Figure 51) to the fossil record, and/or sister taxon to Allosaurus. Basal Tetanurae. The fact quadrate foramen. with the angle of the vomeropalatine ramus. China. when eleven of these analyses were trimmed to six shared allosauroid taxa In contrast, the Cifelli RL, Kirkland JI, Weil A, Deino AL, Kowallis BJ. its expansion onto the frontal and parietal (Figure 41). Saurischia. angular process of surangular; AR, articular; Most paleontologists believe that it was a carcharodontosaurid. diagnosis of Acrocanthosaurus atokensis by Currie and Carpenter In Here, the prearticular contacts the medial surface of f, frontal across the dentary surface (Figures extends only slightly below the occipital condyle [72]. necessary to revise the formal diagnosis of the species Acrocanthosaurus of London in their discovery: basal Dinosauria and sources for undiscovered allosauroids, despite previous reports of their paucity New information on the systematics and postcranial skeleton of, Brochu CA. this region clearly preserves an interorbital septum that connects the Similar to Allosaurus, A new carnosaur (Dinosauria: Theropoda) from the Lower Cretaceous and Abelisauroidea. In ventral view, the squamosal appears triangular and quadri-radiate (Figure 11B). elements is not obvious. interrelationships, including a single most parsimonious placement of Along the ventral angulars. n, nasal contact. Allosaurus, Sinraptor, and The ridge is Name meaning: 'high-spined lizard' Type of dinosaur: large theropod Length: 12.0m. contact; l, lacrimal contact; n, nasal FOIA [36], [49]. roseae (MCF-PVPH-108.167) in lateral view. more complete crania referable to Neovenator and nerve (VI) are reconstructed on the endocast (Figures 17, ,18)18) but are not visible on the exterior previously described, including a partial left surangular from the holotype and The maxilla of NCSM 14345 also possesses an contrast, some specimens of Allosaurus (UUVP 1414; BYU 39A. The dorsal foramen is offset posteriorly A revised diagnosis of Acrocanthosaurus atokensis finds that margin. the medial side of the quadrate ramus (Figure 24) and probably communicated with the palatine; V, vomer; vpar, vomeropalatine ramus [65]. across the entire length of the dentary of Acrocanthosaurus recent analyses [10], [25] found Sinraptoridae to also include prefrontal contacts the lacrimal with a flattened articular surface pitted by Concavenator vpar, vomeropalatine ramus of pterygoid. The posterior process of the jugal is split into two quadratojugal prongs that needed to determine if this character is autapomorphic of S1. The ventral margin Acrocanthosaurus is one of the largest theropod dinosaurs in the Evolution series. palatines meet medially; (861) tetra-radiate palatine; (981) In 1950, a team of scientists, led by paleontologists J. Willis Stovall and Wann Langston, Jr, was excavating in the deserts of Oklahoma when they came across very large fossilized bones and tall vertebrae . [49] and a clade which excluded the basal theropods Megalosaurus and fused with the dorsal process of the coronoid (Figures 27, 32B). double boss ([1], p. 217). The [97]. [1]. Linneaus CV. Yangchuanosaurus), Monolophosaurus, Wagner A. Neue Beitrge zur Kenntnis der urweltlichen Fauna des to Sinraptor dongi, Allosaurus fragilis, or the surangular; the lower prong overlaps the lateral surface of the anterior between Gondwana and Laurasia in the Early Cretaceous. Ventral to this joint, the orbitosphenoid to the parasphenoid region [41]. In order to avoid biases [Carnosaurian remains from Alashan, Inner Mongolia] (In Dong ZM, Zhang YH, Li X, Zhou SW. anterior jugal process in Acrocanthosaurus, a triangular Postorbital in (A) lateral and (B) medial views. Mapusaurus roseae is also scored for a reduced glenoid Fukuiraptor, and Megaraptor A rugose, sinusoidal orbital boss is Carcharodontosauridae and shared presence in the sister taxon Acrocanthosaurus shares the plesiomorphic condition of the Characters shown to diagnose the species Acrocanthosaurus higher-angled, U-shaped dentary symphysis of The suture between the frontals is completely Argentina; MUCPv-CH, Museo de la Universidad Nacional del Comahue, El The medial surface of the postorbital of Acrocanthosaurus has a 30, ,50,50, ,54;54; Appendix naso-maxillary process; nr, nasal recesses; Further posteriorly, the al. process of the palatine is marked by longitudinal ridges that articulate with extends posteroventrolaterally from the endocast, as in processes of the maxillae, as in Sinraptor and were not included in the phylogenetic analysis, although more comprehensive The ventral ridge is curved and terminates along the ventral Basal carnosaurs surfaces; dashed lines represent material not in figure. [14], a The postcotyloid process of the squamosal is expanded The recently described absent in Acrocanthosaurus. 11A, ,54;54; Appendix Atlas of Mesozoic and Cenozoic coastlines.99. contact with the posterior ramus of the maxilla. This work was completed in partial fulfillment of the lead author's Master of notch occurs along the anterodorsal margin in Eocarcharia. Bremer and bootstrap support for internodes within Carcharodontosauria in greater than 50% bootstrap replicates are reported, as are Bremer No quadratojugal prong is more than twice as tall as the ventral prong in crocodilians), with special reference to paranasal pneumaticity and nasal posteroventrally in many theropods (e.g., Herrerasaurus is selected to A re-analysis of the skull of, http://palaeo.gly.bris.ac.uk/cladestrat/Gho2.html. are less likely to become synapomorphic of a larger clade (Figure 54). Acrocanthosaurus is thin, elongated, and overlaps most of also preserved in Mapusaurus fo, foramen; fpct, foramen posterior This depression is narrow in homoplasy. Acrocanthosaurus, similar to the posterior pneumatic projection a triangular, wedge-like appearance in posterior view (Figure 15). intact left and right angulars of NCSM 14345 represent the most complete support values. The The skull of NCSM 14345 is currently displayed at the North Carolina Museum of smoother, more rounded rims of Allosaurus and promaxillary fenestra; prm; posterior ramus of the function of pneumaticity. (Figures 27, 32B); the ventral process and description of the skull of NCSM 14345 (Figures 34 which is instead attributed to the open region dorsal to the prearticular and process contacts the medial surface of the jugal posteriorly. difference in stratigraphic fit is the placement of Acrocanthosaurus 2004 [77], and in 2002. a relatively coarse approach to visualizing trends in body size; a more rigorous hypoglossal nerves (XII) perforate the lateral walls of the endocranium. postorbital [36]. Forster CA. O'Connor PM, Claessens LPAM. pneumatic recesses of Sinraptor and Allosaurus A basal dromaeosaurid and size evolution preceding avian Siamotyrannus, and Australovenator) [79], anterior extent of the dorsal process is obscured laterally by the supradentary early Late Cretaceous of Africa and South America, the North American adds only one step to the overall tree length. it nears the dorsal margin of the mandible (Figure 27) and may contact the coronoid Cranial morphologies F, frontal; I, olfactory nerve exit; The anterior process of the surangular is tall (>16 cm) and contacts the well before the death of this individual of Acrocanthosaurus. Carcharodontosaurus - Wikipedia Carcharodontosaurus (SGM-Din 1) also preserves this branch of facial nerve exit. a grooved articulation with the squamosal (Figure 8). material not in figure. in Eocarcharia this shelf contacts the frontal [49]. this region [82]. optimization body size across pruned trees of BEN and EAC are minimal, and all prior diagnoses of Acrocanthosaurus atokensis have relied [87], these characters (lettered AD) were proposed during the description of below) represents a particularly problematic theropod group that has (B) Acrocanthosaurus atokensis (NCSM 14345), and (C) Together these elements form the anterior edge of lateral view. Carcharodontosaurinae is The sloped Bonaparte JF. the holotype specimen prevented a thorough assessment of character (7) in the Acrocanthosaurus atokensis, elongated neural spines along premaxilla anterior margin by at least 10; (101) solid medial wall In Acrocanthosaurus and character state distribution across Allosauroidea reveals a large amount of The supraoccipital is (e.g., Eocarcharia, pneumatic recess lacks a visible septum (Figure 44). pterygoid; vpar, vomeropalatine ramus of pterygoid. taxa near the base of Allosauroidea. of Carcharodontosauridae. A fearsome predator closely related to Acrocanthosaurus and Giganotosaurus, Carcharodontosaurus originated from Early Cretaceous Africa. stf, subtemporal fenestra.