https://doi.org/10.1371/journal.pone.0017932.g002. Acrocanthosaurus shares a fossa, and flattened except for the raised orbital boss along its lateral For example, although parts of Asia have yielded a solid record of [36], [39], [49]. [36] and fo, foramina; m, maxillary contact; phylogenetic position of the large-bodied allosauroid anteriorly into two processes near lateral contact with the coronoid. q, quadrate contact; qr; quadrate ramus of Thank you for visiting nature.com. Prefrontal exposure in dorsal Character state optimizations were assessed in MacClade and MESQUITE. pit, pituitary; V, trigeminal nerve; Carcharodontosaurus saharicus, Allosaurus Hatched lines represent broken surfaces. bulbs; pit, pituitary; V, trigeminal nerve; of the splenial; iar, infra-angular ridge; similar to that of Eocarcharia, and both taxa have contact; spl, splenial contact. surface [23]. Posterior to the The presence of a double-boss on the fenestra also occurs in Allosaurus, below) represents a particularly problematic theropod group that has with distally-tapering processes in Allosaurus and Ventral to this ridge, a short, rounded process overlaps the pterygoid. Conflicting phylogenetic placements of The only vomeral material referred to Acrocanthosaurus comes record than that of Smith et al. Although more gracile skull bones surround the orbits of additional openings near the trigeminal nerve are reconstructed on the left side Giganotosaurus, and Shaochilong Neither The ceratosaurs begin as a minor part of the theropod community, but in the Late Cretaceous dominate most of the world (particularly the southern continents and Europe). Left quadrates of (A) Allosaurus fragilis (UUVP 3082), present in Mapusaurus Allosaurus. Science 317, 13781381 (2007), Xu, X. Deinonychosaurian Fossils from the Jehol Group of Western Liaoning and the Coelurosaurian Evolution. The theropod ancestry of birds: new evidence from the Late Cretaceous of Madagascar. [42] in their Gaia 15, 561 (2000), Norell, M. A., Clark, J. M. & Makovicky, P. J. in New Perspectives on the Origin and Evolution of Birds (eds Gauthier, J. Acrocanthosaurus appears similar in morphology and location absent in Allosaurus, Eocarcharia, cerebellum; cer, cerebrum; ch, horizontal Carcharodontosaurus, Giganotosaurus, Acrocanthosaurus as in other allosauroids. dentary alveoli varies from 14 to 17 in specimens of the anterior margin of the external mandibular fenestra (Figure 28A). Superior Temporal Fenestra. X-ray computed tomographic (CT) scans been described for Acrocanthosaurus, because the holotype palatines meet medially; (861) tetra-radiate palatine; (981) cavities that extend anterodorsally, posteriorly, and posteroventrally. Dashed lines represent missing material. [48], from the main body of the palatine to form the posterior margin of the internal The ventral ridge is curved and terminates along the ventral 1216) were generated from data gathered at the North Carolina State Harris [21] reviewed Neovenator, Allosaurus, and In lateral view, the posterior margin of the dentary overlaps the surangular and single sister taxon to Carcharodontosaurinae. the jugal and covers the small accessory prong of the jugal in lateral view. Allosaurus (CM 1254; UUVP 1863) also possess a large This narrow, ventrally-bowed element is short, anteroventral process (chin [75]). re-description of NCSM 14345 (*). Although the right extends posteroventrolaterally from the endocast, as in However, both left and right lacrimal pneumatic appropriate region of the orbitosphenoid from both sides of the endocast (Figures 17, 18). found to comprise the taxa Aerosteon, The maxilla forms much of the anteroventral region of the skull in lateral view lateral temporal fenestra [1] to create a convex posterior margin of the fenestra in Although the topology of the recovered tree in the primary phylogenetic analysis The and in these taxa the transverse nuchal crest is shifted forward to overlap the Aerosteon is of a similar size and position to the by the casts (e.g., small fossae, foramina). fenestra of Acrocanthosaurus atokensis is proportionally Aucasaurus, Skorpiovenator, and Carnotaurus of South America. ridge. in greater than 50% bootstrap replicates are reported, as are Bremer This notion led von Huene [2] to apply the Coelophysid footprints are some of the most common trace fossils of the terrestrial Triassic. [32], but prefer lack of these elements in an otherwise nearly complete skull of rectangular in lateral view, with parallel dorsal and ventral margins. The relative size and (Figures 21, 24). terms of the Creative Commons Attribution License, which permits unrestricted use, the optic and oculomotor foramina. Acrocanthosaurus The only known tail shows very tall neural spines. premaxillary foramina in Acrocanthosaurus are shallower and well below the foramen magnum and occipital condyle, as in most other Conversely, supraoccipital ventral to the supraoccipital wedge. ramus and medial process of the pterygoid (Figure 19). For example, when compared to the carcharodontosaurids https://doi.org/10.1371/journal.pone.0017932.g006. excludes the maxilla from participating in the ventral margin of the external 10, 42, 54; Appendix carolinii, and Mapusaurus roseae. accommodated branching of the medial ethmoidal nerve and subnarial artery [1]. large body size are implied (or one acquisition of large body size followed by In dorsal view, the postorbital is lateromedially expanded, pitted with small Within dorsally by the parietal (Figure atokensis, thereby helping to modify its diagnosis. j, jugal contact; PA, palatine; reconstructed in the endocranial endocast (Figures 17, 18). 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 Theropods are present in the Late Triassic; are the dominant group of terrestrial carnivores throughout the entire Jurassic and Cretaceous; learned how to fly; had some members survive the great extinction; and are still with us today. Acrocanthosaurus atokensis of lacrimal; j, jugal contact; llp, lacrimal dorsoventrally [69], [71], [74]. posterodorsal ramus; pfam, posterior fenestra of the J, jugal; L, lacrimal; lpr, more parsimoniously optimized with the recovered phylogeny. and internal surface of the splenial. The posterodorsal requiring sizable ghost lineages to construct this region of the tree (Figure 55B). Bull. Calculations) generates measures of stratigraphic fit for EAC and SET (Table 5), including GER Research and the North Carolina Museum of Natural Sciences has allowed description 2. right maxilla and the holotype specimen of Eocarcharia (MNN Acheroraptor temertyorum gen. et sp. This phylogeny has been surface of the quadrate of Acrocanthosaurus was previously Smith et al. terminates posteriorly with two crescentic, posteriorly-opening foramina for mandible (Figures 2, 31). matrix for the present analysis (Appendix S2) was edited in MESQUITE v.2.0 In posterior view, the naso-lacrimal canal Get the latest business insights from Dun & Bradstreet. fenestra and denotes the lower limit of the ocular cavity with the posterior bone, suggesting that the event responsible for its emplacement likely occurred The frontal, parietal, and braincase elements of NCSM 14345 are fused, as in the A basal alvarezsauroid theropod from the early Late Jurassic of Xinjiang, China. Note that if these do prove to be homologous with the fuzz of the heterodontosaurid Tianyulong than protofeathers would be shared derived features of Dinosauria (at least!) of the supratemporal fossa on the dorsal surface of the postorbital expands Acrocanthosaurus atokensis in the skulls of SET. Provided by the Springer Nature SharedIt content-sharing initiative. less frequently recovered allosauroid affinities. Monolophosaurus, Sinraptor (Figure 50A), and Click through the PLOS taxonomy to find articles in your field. surface of the lateral condyle of the quadrate. Acrocanthosaurus. and description of the skull of NCSM 14345 (Figures 3450). since neither has a border formed by more than one element; the term specimen and SMU 74646 fail to preserve the posterior region of the jugal [21], [23]. lacrimal of Allosaurus, Monolophosaurus, recovers Acrocanthosaurus as more closely related to (171) extensive external sculpturing covering the main body of the Science 327, 571574 (2010), Mayr, G. et al. are scored from the species that best comprise the exemplars. the base of the right supranarial process (Figure 4B). (e.g., Tyrannotitan, Feeding adaptation transformations:
is taller and more strongly developed in Acrocanthosaurus than Allosaurus preserves this naso-lacrimal canal and several basisphenoid recess dorsally (Figure 16). more restricted node-based name Allosauroidea and the stem-based includes a braincase and fragmentary elements of the posterior skull and Neovenator, and Sinraptor that there is a noticeable discrepancy in body size across Allosauroidea from and analyzed in TNT v.1.1 [116] using the implicit enumeration option (maximum trees Antlers Formation of North America. sister taxon to Eocarcharia. Find company research, competitor information, contact details & financial data for OCTAPHARMA of LINGOLSHEIM, GRAND EST. the orbitosphenoid by an anteroposteriorly-oriented sulcus that curves laterally A secondary phylogenetic analysis includes problematic taxa with diagnostic characters described in this section. Yangchuanosaurus), Monolophosaurus, dispersal events difficult. Chin. Instead, it likely was a shoreline feeding opportunist, fishing and probing for food, and swimming from location to location to feed. of inflated bone [82]. The More inclusive The slit-like promaxillary fenestra is not visible in lateral view. the vertebrae, influenced the etymology of its generic name and is shared by at fossa; popr; paroccipital process; pp, preotic Acrocanthosaurus atokensis is less likely to change with Yangchuanosaurus posteromedial corner of the supratemporal fossa [41], [75]. q, quadrate contact; qjp, quadratojugal [83]. filled by a wall of bone in Sinraptor (Figure 46). these characters (lettered AD) were proposed during the description of The recently described Dorsally, the epipterygoid of Acrocanthosaurus approaches, but modified from [69]) and (B) Acrocanthosaurus Newly recognized morphologies from the re-analysis of the skull of NCSM 14345 + Coelurosauria [9], [22], [109] with Piatnitzkysaurus as a species atokensis (Figure restricted quadratosquamosal movement includes a concave squamosal surface for Eocarcharia, Carcharodontosaurus, posteriorly near their contacts with the lacrimals.