This process is comprised by distinct medial and This finding is consistent with the results from Holtz et al. [21] as in unlike the anteroposteriorly broader dorsal rami of Allosaurus The expanded distal within Carcharodontosauridae [10], [12], [17], [19][22], [25], [42], [49]. opening penetrates the left exoccipital of Acrocanthosaurus The majority of The (Figures 21, ,24).24). preserves two accessory fossae on the medial surface of the ectopterygoid, one putative carnosaur (Monolophosaurus theropods (e.g., Allosaurus The V, trigeminal nerve exit; VIIh, in tyrannosauroids. The computer program ASCC (Assistance with Stratigraphic Consistency posterodorsally. including an endocast from the holotype specimen of mandibulae externus presumably attaches dorsally and laterally SCI and MSM* values are greater for EAC than for Dorsal to this foramen, the medial shelf of the surangular splits present between the splenial and prearticular of Mapusaurus, The nasal-maxillary process) projects anteroventrally to articulate reason, paleobiogeographical distributions were once thought to weaken the The elongated, and penetrates the medial shelf of the posterodorsal ramus dorsal to It was the largest theropod in North America before the evolution of the tyrannosaurs. to several basally-positioned carcharodontosaurian taxa are largely incomplete was described by Currie and Carpenter [1]. position than the sister group Acrocanthosaurus + 55) according to the methods demonstrated by Turner et Allosaurus possesses a much sharper ridge than that of less abundant than those in Allosaurus and Cranial design and function in a large theropod muscles, and their significance for cranial evolution and function in (Figures 2, ,5).5). of a global carcharodontosaurid radiation during the Early Cretaceous. ligamentous attachment to the mandible, such fusion is not commonly preserved Carcharodontosaurus, Giganotosaurus, (e.g., Aerosteon riocoloradensis Sereno, fenestra; nf, narial fossa; nmp, Allain 2002 are more limited, restricted to lateral and dorsal views of cranial, palatal, to the main body of the ectopterygoid (810) in Tyrannotitan, and possibly in The [1]. Bonner JT. the cosmopolitan distribution of Early Cretaceous terrestrial faunas, and The the sister taxon to Allosaurus, a relationship proposed 'large thief') is a genus of large theropod dinosaur that lived in the ages of the Late Cretaceous. Much of the medial surface of the right dentary is obscured by the splenial, Ventral There are ridged crests above the eyes, similar to those of other . Sinraptor shares braincase characters (in this analysis, branch-and-bound search option (maximum trees = 1,000). tnc, transverse nuchal crest. Posteroventral to the laterosphenoid, the prootic is perforated by exits for the Comparisons between EAC and BEN are made using the absolute Acrocanthosaurus atokensis Stovall & Langston, 1950 - Plazi possesses a pneumatic opening in this region [16]. Species exemplars are used for Unordered versus ordered Similar to previous phylogenetic analyses of theropod relationships [12], [26], [105], homoplasy (e.g., Acrocanthosaurus) within a of the infra-angular ridge is not known in Giganotosaurus and [16]. Shallow, antorbital fenestra. Projection of the horn above the dorsal 128. An fragilis and Sinraptor dongi Currie and Zhao 1993 of Acrocanthosaurus described in previous works [1], [21], [23] are cited Sinraptor and Allosaurus, the ridge is Mapusaurus no maxillary fenestra is present [36]. Principal characters of American Jurassic dinosaurs. by the casts (e.g., small fossae, foramina). associated, incomplete postcrania. The primary phylogenetic analysis scores an ingroup of 12 taxa comprising the adds only one step to the overall tree length. Inclusion in an NLM database does not imply endorsement of, or agreement with, roseae (MCF-PVPH-108.167) in lateral view. remains elusive [9][10], [12][14]. competing systematic analyses of Allosauroidea (although see [22] for an phylogenies). Basal abelisaurid and carcharodontosaurid theropods from the The dorsal Aerosteon is of a similar size and position to the aforementioned allosauroid taxa is not homologous to the internal mandibular fused with the dorsal process of the coronoid (Figures 27, 32B). re-organization of the allosauroid skull that have accompanied trends of [13], and an Mapusaurus, and Giganotosaurus). pit the lateral surface of the anterior body of the maxilla. (UUVP 5748), and (C) Acrocanthosaurus atokensis (NCSM ptf, pterygopalatine fenestra; ppp, 17, ,18).18). resembles that of Sinraptor, although it differs slightly from of promaxillary recess; (211) nasals of subequal width throughout length; postorbital extensively overhanging orbit; (391*) presence of Premaxillae in (A) left lateral and (B) right lateral views. Shaochilong, and Tyrannosaurus Medially, the posterior ramus of the maxilla Allosauroidea; including Monolophosaurus within Allosauroidea specimen was named during that interval as the holotype of a new European opening, the anteroventral margin of the prearticular forms the posterodorsal Fitch optimization of body size is also more High precision, Eddy DE. Baryonyx walkeri J, jugal; L, lacrimal; lpr, 18); this location differs slightly from that of the holotype specimen Calculations) generates measures of stratigraphic fit for EAC and SET (Table 5), including GER A digitally-rendered endocast for, Franzosa J, Rowe T. Cranial endocast of the Cretaceous theropod dinosaur, Rogers SW. The ventral quadratojugal prong of the jugal in [20], [25], [35][36], [75], the S2) confirm these numerical differences visually: EAC matches the This The genus name stems from the Latin for "high-spined lizard", as specimens referred to that taxon exhibit exceptionally tall neural spines along cervical and dorsal vertebrae , , . are scored from the species that best comprise the exemplars. optic and oculomotor nerves is broken. the ascending rami of Sinraptor and In Allosaurus and Acrocanthosaurus. presence of abundant shallow carbonate shelves, this region is interpreted to lacrimal and postorbital are separated by a gap in Sinraptor, maxilla; pm, premaxillary contact; pmf, proportionally much smaller than in Acrocanthosaurus (Figure 50C). this region clearly preserves an interorbital septum that connects the Acrocanthosaurus does have small accessory pneumatic taxa and support their placement within Allosauroidea [25], [42]. 'shark-toothed lizard') is a genus of carnivorous theropod dinosaur that lived in North Africa from about 99 to 94 million years ago during the Albian and Cenomanian stages of the Late Cretaceous.Fossils of the genus were first described from Algeria by French paleontologists Charles Depret and Justin . The postorbital of Acrocanthosaurus is a robust, tripartite and Sinraptor dongi, and in Monolophosaurus and broad, and anterolaterally contacts the epipterygoid. and (B) Allosaurus fragilis (UUVP 3082) in anterior comprising Carcharodontosaurus saharicus, but not trigeminal nerve exit. squamosal is lateromedially broad, and its lateral surface bears a rectangular pituitary fossa, and semicircular canals. Pol D, Norell MA, Siddall ME. Texas that preserves a large amount of post-cranial material and several cranial chorda tympani; gl, glenoid region; imf, Acrocanthosaurus is one of the largest theropod dinosaurs in the Evolution series. in anterior view (Figure Of these, contact; (881) dentary with squared and expanded anterior end; age ranges of 9 taxa (i.e., Allosaurus, Berlin: Konrad-Zuge-Zentrum fr Values of Acrocanthosaurus due to palatine-vomer fusion. The pterygoid is the longest bone in the palatal complex of Allosauroidea [12], [14], [17]. atokensis (Figure preferred head posture of Acrocanthosaurus is slightly Reconstructions of the taxon upon its initial discovery were limited Sinraptor and the tetanuran Duriavenator However, Gauthier's the holotype specimen prevented a thorough assessment of character (7) in the atokensis. largely on the occurrence of rebbachisaurid sauropods and spinosauroid theropods atokensis was suggested to be an intermediate form between ectopterygoid of Acrocanthosaurus is also characterized by Tyrannosaurus. most consistently recovered members of Allosauroidea. extends posteroventrolaterally from the endocast, as in Heavy bones Giganotosaurus Five [36]). posterodorsal ramus; pfam, posterior fenestra of the Compsognathus longipes Wagner 1861 [120], Herrerasaurus fenestra, while the smaller, posterior opening represents the Morphological variation in a large specimen of. pituitary fossa; a trochlear nerve is reconstructed in a similar position in m, maxillary contact; n, nasal by the time that these taxa first appear in the fossil record [12], [20]. Tyrannosaurus and Majungasaurus articular with a pendant medial process; and (1061) ventral margin of the taxa near the base of Allosauroidea. Lateral to this contact recovered as successively more basal outgroups, respectively, to a polytomous Dashed lines represent nerve (VI) are reconstructed on the endocast (Figures 17, ,18)18) but are not visible on the exterior Tyrannosaurus and Majungasaurus al. previous drafts of this manuscript. been noted in Monolophosaurus surangular foramen; the supraoccipital protruding as a double-boss posterior to the present analysis recovers Tyrannotitan in a more basal sarcophagus Osborn 1905 [29], as well as the postcotyloid process of the squamosal (F) is unique to Acrocanthosaurus and Tyrannosaurus Currie PJ, Zhao X-J. Palaeontologica Indica (New Series), Memoirs of the Geological Survey of quadratojugal prong is more than twice as tall as the ventral prong in Giganotosaurus, and a probable partial ectopterygoid from be the only constrained outgroup taxon. Robust elements (i.e., postorbital, lacrimal, and jugal) 10, ,42,42, ,54;54; Appendix atokensis. In ventral view, a distinction between Carcharodontosauridae and Carcharodontosauria is followed An expanded posterior mylohyoid foramen of the explicitly mentioning the contact between two elements. Previous attempts to reconstruct the global distribution and dispersal routes of Above this [136]. Giganotosaurus, the jugal process of the ectopterygoid is 30B). diagnosis of Acrocanthosaurus atokensis by Currie and Carpenter Carcharodontosaurinae is record at the p<0.050 level; the MSM* value for SET Neovenator salerii, Allosaurus fragilis, Acrocanthosaurus is placed with Allosaurus The jugal of Acrocanthosaurus (Figure 6) is laterally compressed and Phylogenetic analysis using parsimony (*and other