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, 11 (7), e0157973
eCollection

A New Megaraptoran Dinosaur (Dinosauria, Theropoda, Megaraptoridae) From the Late Cretaceous of Patagonia

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A New Megaraptoran Dinosaur (Dinosauria, Theropoda, Megaraptoridae) From the Late Cretaceous of Patagonia

Rodolfo A Coria et al. PLoS One.

Abstract

A skeleton discovered in the Upper Cretaceous Sierra Barrosa Formation (Turonian-Coniacian) of Neuquén Province, Argentina represents a new species of theropod dinosaur related to the long snouted, highly pneumatized Megaraptoridae. The holotype specimen of Murusraptor barrosaensis n.gen et n.sp. (MCF-PVPH-411) includes much of the skull, axial skeleton, pelvis and tibia. Murusraptor is unique in having several diagnostic features that include anterodorsal process of lacrimal longer than height of preorbital process, and a thick, shelf-like thickening on the lateral surface of surangular ventral to the groove between the anterior surangular foramen and the insert for the uppermost intramandibular process of the dentary. Other characteristic features of Murusraptor barrosaensis n.gen. et n. sp.include a large mandibular fenestra, distal ends of caudal neural spines laterally thickened into lateral knob-like processes, short ischia distally flattened and slightly expanded dorsoventrally. Murusraptor belongs to a Patagonian radiation of megaraptorids together with Aerosteon, Megaraptor and Orkoraptor. In spite being immature, it is a larger but more gracile animal than existing specimens of Megaraptor, and is comparable in size with Aerosteon and Orkoraptor. The controversial phylogeny of the Megaraptoridae as members of the Allosauroidea or a clade of Coelurosauria is considered analyzing two alternative data sets.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. A) Skull reconstruction of Murusraptor barrosaensis, MCF-PVPH-411. B) Body reconstruction of Murusraptor barrosaensis, MCF-PVPH-411.
Both illustrations show recovered elements in white. Scale bars: A = 10 cm, B = 1 m.
Fig 2
Fig 2. Location and geological context of the holotypeof Murusraptor barrosaensis, MCF-PVPH-411.
A) Star marks collecting locality of holotype. B) Stratigraphic table and geologic section indicating the provenance of the megaraptorins recorded in the Neuquén group (modified from [41]).
Fig 3
Fig 3. Field photos of the excavation of MCF-PVPH-411 (Murusraptor barrosaensis).
A and B, the authors excavating the right ilium. C-F, different appendicular elements in their original burial positions before collection.
Fig 4
Fig 4. Right lacrimal and postorbital of Murusraptor barrosaensis, holotype, MCF-PVPH-41.
Lacrimal in lateral (A) and medial (B) views. Postorbital in lateral (C) and medial (D) views. Abbreviations: ap, anterodorsal process; fp, frontal process; gr, groove from pneumatopores to antorbital fenestra; js, jugal suture; ld, lacrimal duct; lns, nasal suture limit; lr; lacrimal recess; lsc, laterosphenoid contact; ms, maxillary suture; msv, posterior limit of ventral contact with posterodorsal process of maxilla; ns, nasal suture; pdp, posterodorsal process; pn, pneumatopores; prf, prefrontal contact; pro, preorbital process; sp, squamosal process; ss, squamosal suture; sur, anterior tip of surangular; vl, ventral limit of prefrontal in lateral view; vp, ventral process. Scale bar: 10 cm.
Fig 5
Fig 5. Right prefrontal of Murusraptor barrosaensis, holotype, MCF-PVPH-411.
Prefrontal in dorsal (A), lateral (B), medial (C) and ventral (D) views. Prefrontal in articulation with frontal and lacrimal in dorsal (E) and lateral views (F). G) lateral view of prefrontal separated from the lacrimal. Abbreviations: f, frontal; fc, frontal contact; fp, frontal process of prefrontal; l, lacrimal; lap, lacrimal process of prefrontal; lc, lacrimal contact; ns, nasal suture of frontal; om, orbital margin; prf, prefrontal. Scale bars: 10 cm.
Fig 6
Fig 6. Braincase of Murusraptor barrosaensis, holotype, MCF-PVPH-411. Braincase in dorsal (A), lateral (B), anterior (C), ventral (D) and posterior (E,E’) views; occipital condyle in ventral view, photography (F) and line drawing (F’).
Abbreviations: bo, basioccipital; bp, basipterygoid process; bs, basisphenoid; bsp, basipterygoid; br, basisphenoidal recess; cn, condylar neck; cp, cultriform process; ec, endocranial cavity; exo, exoccipital-opisthotic; f, frontal; fm, foramen magnum; fov, fenestra ovalis; io, interorbital slot between prefrontal/lacrimal and postorbital; n/p, nasal/prefrontal contact; lat, laterosphenoid; np, nasal pit; oc, occipital condyle; op, opistotic; orb, orbitosphenoid; p, parietal; path, pathology; pit, pituitary fossa; pn, pneumatopore; po, postorbital contact; pof, postorbital suture of the frontal; pop, paraoccipital process; pr, prootic; prp, prefrontal pit; soc, supraoccipital; vcdf, vena capitis dorsalis foramen; II, second cranial nerve exit; III, third cranial nerve exit; V, trigeminal (fifth cranial nerve) exit; V1, ophthalmic branch of the trigeminal exit; VI, sixth cranial nerve exit; IX-XI, exit for ninth to eleventh cranial nerves. Scale bar: 10 cm.
Fig 7
Fig 7. Sphenethmoids of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in right lateral (A), anterior (B) and ventral (C) views.
Abbreviations: fc, frontal contact; s, medial septum. Scale bar: 10 cm.
Fig 8
Fig 8. Quadrate of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in lateral (A), medial (B), anterior (C), posterior (D) and distal (E) views.
Abbreviations: lcq, lateral condyle of quadrate; mcq, medial condyle of quadrate; pn, pneumatopore; ptf, pterygoid flange; pts, pterygoid suture; qc, quadrate cotyle; qf, quadrate foramen; qjs, quadrate-jugal suture. Scale bar: 10 cm.
Fig 9
Fig 9. Pterygoid of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in lateral view.
Abbreviations: bpp, basipterygoid process; ep, ectopterygoid process; epi, epipterygoid; pp, palatal process; qfl, quadrate flange; vp, vomerine process. Scale bar: 10 cm.
Fig 10
Fig 10. Ectopterygoid of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in dorsal view.
Abbreviations: jc, jugal contact; jp, jugal process; ptc, pterygoid contact; stf, subtemporal fenestra. Scale bar: 10 cm.
Fig 11
Fig 11. Articulated postdentary elements of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in lateral (A) and medial (B) views.
Abbreviations: a, angular; ar, articular; lt, lateral thickening; pra, prearticular; psf, posterior surangular foramen sa, surangular. Scale bar: 10 cm.
Fig 12
Fig 12. Surangular of Murusraptor barrosaensis, holotype, MCF-PVPH-411in dorsal (A) and medial (B) views.
Abbreviations: adfp, posterior wall of the adductor fossa; arts, articular suture; asf, anterior surangular foramen; cs, back of coronoid suture; gsa, glenoid contribution of surangular; ld, longitudinal depression for insertion of the M. adductor mandibulae externus; lt, lateral thickening; pras, prearticular suture; psf, posterior surangular foramen; ret, retroarticular process. Scale bar: 10 cm.
Fig 13
Fig 13. Angular of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in lateral (A) and medial (B) views.
Abbreviations: de, contact for dentary; pac, prearticular contact; sa, contact for surangular. Scale bar: 10 cm.
Fig 14
Fig 14. Prearticular of Murusraptor barrosaensis, holotype, MCF-PVPH-411in lateral (A) and medial (B) views.
Abbreviations: aar, articulation for the articular; an, contact for the angular; co, contact for the coronoid; imf, posterior margin of the internal mandibular fenestra; pa, process for articular. Scale bar: 10 cm.
Fig 15
Fig 15. Left Articular of Murusraptor barrosaensis, holotype, MCF-PVPH-41.
Articular in posterior (A), dorsal (B) and ventral (C) views. Abbreviations: ctaf, chorda tympani anterior foramen; ctpf, chorda tympani posterior foraman; dm, insertion area for M.depressor mandibulae; g, vascular groove; ir, interglenoid ridge; mg, medial glenoid; ret, retroarticular process; sac, surangular contact; vr, ventral ridge. Scalebar: 10 cm.
Fig 16
Fig 16. Maxillary teeth of Murusraptor barrosaensis, holotype, MCF-PVPH-411.
Left? maxillary tooth MCF-PVPH-411-50 in mesial (A), posterior (B) and labial (C) views. Maxillary tooth MCF-PVPH-411-79 in mesial view (D) and close-up of posterior denticles. Scalebar: 1 cm.
Fig 17
Fig 17. Twelfth presacral neural arch of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in dorsal (A), anterior (B) and posterior (C) views.
Abbreviations: cdpl, centrodiapophyseal lamina; dp, diapophysis; il, interspinus ligament scar; nc, neural canal; ns, neural spine; pob, postspinal basin; pn, pneumatopores; pp, parapophysis; prz, prezygapophisys; pz, postzygapophysis. Scale bar: 10 cm.
Fig 18
Fig 18. Neural arches of the sixteenth presacral and the third or fourth sacral vertebra of Murusraptor barrosaensis, holotype, MCF-PVPH-411. Sixteenth presacral vertebrae in dorsal (A), anterior (B), lateral (C) and posterior (D) views.
Third or fourth sacral vertebra in (E-E’) anterior and (F-F’) lateral views. Abbreviations: dp, diapophysis; hy, hyposphene; ils, interspinous ligament scar; nc, neural canal; ns, neural spine; pp, parapophysis; prz; prezygapophyses; pz, postzygapophyes; tnc, tube-like neumatic canal. Scale bar: 10 cm.
Fig 19
Fig 19. Anterior caudal neural arch of Murusraptor barrosaensis, holotype, MCF-PVPH-411in dorsal (A), anterior (B), lateral (C) and posterior (B) views.
Abbreviations: acdpl, anterior centrodiapophyseal lamina; idf, infradiapophyseal fossa; ns, neural spine; pcdpl, posterior centrodiapophyseal lamina; pz, postzygapophyses; tp, transverse process. Scale bar: 10 cm.
Fig 20
Fig 20. Presacral ribs of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in anterior views.
A) 11th presacral rib with close-up of pathological area. B) 17th presacral ribs with close-up of pathological area. Abbreviations: c, capitulum; t, tuberculum. Scale bar: 10 cm.
Fig 21
Fig 21. Gastralia of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in ventral view.
a-c, anteriormost elements; d-f, most posterior elements. Relative positions are tentative as well as reconstructed areas. Scale bar: 10 cm.
Fig 22
Fig 22. Manual ungual of Murusraptor barrosaensis, Holotype, MCF-PVPH-411 side views.
Abbreviations: at, anterior tip; vg, vascular groove. Scale bar: 1 cm.
Fig 23
Fig 23. Ilium of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in lateral (A) and medial (B) views.
Abbreviations: a, acetabulum; at, antitrochanter shelf; cf, cuppedicus fossa; ip, ischial peduncle; pab, preacetabular blade; pap, postacetabular process; pn, pneumatopores; pp, pubic peduncle. Scale bar: 10 cm.
Fig 24
Fig 24. Pubis of Murusraptor barrosaensis, holotype, MCF-PVPH-411 (A, C) compared with the pubis of Megaraptor namunhuaiquii MUCPv 341 (B, D) in proximal (A, B) and lateral (C, D) views.
Abbreviations: ac, acetabulum; ilp, iliac peduncle; isp, ischial peduncle; pn, pneumatopores. Scale bar: 10 cm.
Fig 25
Fig 25. Ischia of Murusraptor barrosaensis, holotype, MCF-PVPH-411.
Left ischium (A) and right ischium (B) in medial views. Abbreviations: op, obturator process; is, ischial symphysis. Scale bar: 10 cm.
Fig 26
Fig 26. Tibia of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in medial (A), anterior (B), posterior (C), lateral D), proximal (E) and distal views.
Abbreviations: ac, astragalar contact; cc, cnemial crest; cf, crista fibularis; ig, intercondylar groove; it, incisura tibialis; lc, lateral condyle; pmc, posteromedial condyle. Scale bar: 10 cm.
Fig 27
Fig 27. Calcaneum of Murusraptor barrosaensis, holotype, MCF-PVPH-411 in lateral (A), medial (B), distal (C) and proximal (D) views.
Abbreviations: ac, astragalar contact; fc, fibular contact; tc, tibial contact. Scale bar: 1 cm.
Fig 28
Fig 28. Comparison of right ilia of Murusraptor (A) and Aerosteon (B) in lateral views.
Scale bar: 10 cm.
Fig 29
Fig 29. Cladogram depicting the phylogenetic position of Murusraptor according Analysis A.
Numbers in nodes indicate Bremer support.
Fig 30
Fig 30. Cladogram depicting the phylogenetic position of Murusraptor according Analysis B.
Numbers in nodes indicate Bremer support.

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Grant support

Funding was provided by Consejo Nacional de Investigaciones Cientificas y Tecnicas, PIP-0233, RAC National Sciences and Engineering Reserach Council grant #203091-06, PJC, Troodon Resources, Dinosaur Research Institute and Municipalidad de Plaza Huincul. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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