Appendicular osteology of<i>Dreadnoughtus schrani</i>, a giant titanosaurian (Sauropoda, Titanosauria) from the Upper Cretaceous of Patagonia, Argentina

Ullmann, Paul V.; Lacovara, Kenneth J.

doi:10.1080/02724634.2016.1225303

Cited by 29 publications

(33 citation statements)

References 79 publications

(68 reference statements)

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“…The fibular shaft is also strongly sigmoidal in posterior view, with the lateral surface markedly convex at level of the biceps tubercle ( Figure 23C). In general terms, the fibula is similar to that of Dreadnoughtus (Ullman & Lacovara, 2016). The sigmoid curve present in both Nullotitan and Dreadnoughtus is exaggerated in lateral view, for the notable anteroposterior expansion of both proximal and distal ends of the bone.…”

Section: Sauropoda Marsh 1878mentioning

confidence: 78%

Paleontological discoveries in the Chorrillo Formation (upper Campanian-lower Maastrichtian, Upper Cretaceous), Santa Cruz Province, Patagonia, Argentina

Novas¹,

Agnolín²,

Rozadilla³

et al. 2019

MACN

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The first fossil remains of vertebrates, invertebrates, plants and palynomorphs of the Chorrillo Formation (Austral Basin), about 30km to the SW of the town of El Calafate (Province of Santa Cruz), are described. Fossils include the elasmarian (basal Iguanodontia) Isasicursor santacrucensis gen. et sp. nov., the large titanosaur Nullotitan glaciaris gen. et sp. nov., both large and small Megaraptoridae indet., and fragments of sauropod and theropod eggshells. The list of vertebrates is also composed by the Neognathae Kookne yeutensis gen. et sp. nov., two isolated caudal vertebrae of Mammalia indet., and isolated teeth of a large mosasaur. Remains of fishes, anurans, turtles, and snakes are represented by fragmentary material of low taxonomical value, with the exception of remains belonging to Calyptocephalellidae. On the other hand, a remarkable diversity of terrestrial and freshwater gastropods has been documented, as well as fossil woods and palinological assemblages. The Chorrillo Formation continues south, in the Las Chinas River valley, southern Chile, where it is called Dorotea Formation. Both units share in their lower two thirds abundant materials of titanosaurs, whose remains cease to appear in the upper third, registering only elasmarians (Chorrillo Formation) and hadrosaurs (Dorotea Formation). Above both units there are levels with remains of invertebrates and marine reptiles. It is striking that the dinosaurs of the lower two thirds of the Chorrillo and Dorotea formations are represented by large basal titanosaurs and Megaraptoridae coelurosaurs, being the Saltasaurinae and Aeolosaurinae sauropods and Abelisauridae theropods totally absent. In contrast, these taxa are dominant components in sedimentary units of central and northern Patagonia (e.g., Allen, Los Alamitos, La Colonia formations). Such differences could reflect, in part, a greater antiquity (i.e., late Campanian-early Maastrichtian) for the Chorrillo fossils, or, more probably, different environmental conditions. Thus, knowledge of the biota of the southern tip of Patagonia is expanded, particularly those temporarily close to the K-Pg boundary.

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Section: Sauropoda Marsh 1878mentioning

confidence: 78%

Paleontological discoveries in the Chorrillo Formation (upper Campanian-lower Maastrichtian, Upper Cretaceous), Santa Cruz Province, Patagonia, Argentina

Novas¹,

Agnolín²,

Rozadilla³

et al. 2019

MACN

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“…The origin of the M. puboischiofemoralis internus II is equivocal in dinosaurs, whereas the insertion is unequivocal (Dilkes, 2000, figs 14 and 16; Carrano & Hutchinson, 2002; Maidment & Barrett, 2011). On the ilia of Dreadnoughtus , there is an accessory process on the ventrolateral margin of the preacetabular lobe (Figure 3; Ullmann & Lacovara, 2016). Ullmann and Lacovara (2016) additionally reported this process as present in specimens of Alamosaurus and Giraffatitan , in the location of the avian origin of the M. puboischiofemoralis internus II.…”

Section: Resultsmentioning

confidence: 99%

“…On the ilia of Dreadnoughtus , there is an accessory process on the ventrolateral margin of the preacetabular lobe (Figure 3; Ullmann & Lacovara, 2016). Ullmann and Lacovara (2016) additionally reported this process as present in specimens of Alamosaurus and Giraffatitan , in the location of the avian origin of the M. puboischiofemoralis internus II. There are no discernable osteological correlates at this location on the right ilium of the paratype (MPM‐PV 3546‐16) or the left ilium of the holotype (MPM‐PV 1156‐52) of Dreadnoughtus , but the left ilium of the paratype (MPM‐PV 3546‐15) and right ilium of the holotype (MPM‐PV 1156‐53) exhibit possible striations on this process.…”

Section: Resultsmentioning

confidence: 99%

“…The appendicular skeleton of Dreadnoughtus is conducive to detailed myological study because: (1) at least one of every stylopodial and zeugopodial element is preserved between the holotype and paratype individuals and; (2) these bones retain excellent surface texture, including numerous osteological correlates (Lacovara et al, 2014; Ullmann & Lacovara, 2016). Furthermore, Dreadnoughtus is significantly larger bodied than other titanosaurians for which myological data are currently available, and in cladistic analyses this giant taxon often occupies a moderately derived phylogenetic position compared to those of related taxa with reconstructed myology: Opisthocoelicaudia (Borsuk‐Bialynicka, 1977); Neuquensaurus (Otero & Vizcaíno, 2008); Epachthosaurus (Ibiricu et al, 2018); and Diamantinasaurus (Klinkhamer et al, 2018, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Myological reconstruction of the pelvic girdle and hind limb of the giant titanosaurian sauropod dinosaur Dreadnoughtus schrani

et al. 2020

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Osteological correlates preserve more readily than their soft tissue counterparts in the fossil record; therefore, they can more often provide insight into the soft tissue anatomy of the organism. These insights can in turn elucidate the biology of these extinct organisms. In this study, we reconstruct the pelvic girdle and hind limb musculature of the giant titanosaurian sauropod Dreadnoughtus schrani based on observations of osteological correlates and Extant Phylogenetic Bracket comparisons. Recovered fossils of Dreadnoughtus exhibit remarkably well‐preserved, well‐developed, and extensive muscle scars. Furthermore, this taxon is significantly larger bodied than any titanosaurian for which a myological reconstruction has previously been performed, rendering this contribution highly informative for the group. All 20 of the muscles investigated in this study are sufficiently well supported to enable reconstruction of at least one division, including reconstruction of the M. ischiocaudalis for the first time in a sauropod dinosaur. In total, 34 osteological correlates were identified on the pelvic girdle and hind limb remains of Dreadnoughtus, allowing the reconstruction of 14 muscles on the basis of Level I or Level II inferences (i.e., not Level I' or Level II' inferences). Comparisons among titanosaurians suggest widespread myological variation, yet potential phylogenetic and other paleobiologic patterns are often obscured by fragmentary preservation, infrequent myological studies, and lack of consensus on the phylogenetic placement of many taxa. However, a ventrolateral accessory process is present on the preacetabular lobe of the ilium in all of the largest titanosauriforms that preserve this skeletal element, suggesting that the presence of this process (representing the origin of the M. puboischiofemoralis internus part II) may be associated with extreme body size. By identifying such myological patterns among titanosauriforms, we can begin to address specific evolutionary and biomechanical questions related to their skeletal anatomy, how they were capable of leaving wide‐gauge trackways, and resulting locomotor attributes unique to this clade.

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“…These closely spaced foramina may represent a late stage ontogenetic state or be expressed through much or all of ontogeny in individuals from the lowest HCF. The migration of foramina through ontogeny has been noted in several vertebrate groups, (e.g., Watson 1963;Williams and Krovitz 2004) including dinosaurs (Ullmann and Lacovara 2016). If Triceratops and 'Torosaurus' are distinct but closely related taxa, the morphology of these foramina might suggest MOR 1122 7-22-00-1 holds affinities with the latter.…”

Section: Premaxillamentioning

confidence: 98%

A chasmosaurine ceratopsid premaxilla from the basal sandstone of the Hell Creek Formation, Montana

Scannella

2020

Vert. Anat. Morph. Palaeo.

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A well-preserved large chasmosaurine ceratopsid premaxilla (MOR 1122 7-22-00-1) collected from the basal sandstone of the Cretaceous Hell Creek Formation (HCF) represents one of the stratigraphically lowest ceratopsid occurrences in the formation. The specimen was discovered in 2000, during the excavation of a large Torosaurus latus skull (MOR 1122) which was later hypothesized to represent an advanced growth stage of the more commonly recovered HCF ceratopsid Triceratops. MOR 1122 7-22-00-1 compares favorably with the incomplete premaxillae of the MOR 1122 skull and reveals details of premaxilla morphology from this stratigraphic zone. It preserves large, closely spaced ventromedial foramina, a narrow triangular process, and a thin septal flange at the base of the narial strut. The nasal process is narrow, caudally inclined and has a forked dorsal surface which appears to represent an intermediate between the morphology expressed in the slightly stratigraphically lower ceratopsid Eotriceratops xerinsularis from the Horseshoe Canyon Formation of Alberta and specimens recovered higher in the HCF. MOR 1122 7-22-00-1 expresses a deep recess extending medial to the strut of the triangular process, a feature shared with other HCF ceratopsid specimens but not Eotriceratops or other earlier occurring triceratopsin taxa. The morphology of MOR 1122 7-22-00-1 is consistent with noted stratigraphic trends in HCF ceratopsids and highlights the increased complexity of the narial region in uppermost Cretaceous triceratopsins.

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Appendicular osteology ofDreadnoughtus schrani, a giant titanosaurian (Sauropoda, Titanosauria) from the Upper Cretaceous of Patagonia, Argentina

Cited by 29 publications

References 79 publications

Paleontological discoveries in the Chorrillo Formation (upper Campanian-lower Maastrichtian, Upper Cretaceous), Santa Cruz Province, Patagonia, Argentina

Paleontological discoveries in the Chorrillo Formation (upper Campanian-lower Maastrichtian, Upper Cretaceous), Santa Cruz Province, Patagonia, Argentina

Myological reconstruction of the pelvic girdle and hind limb of the giant titanosaurian sauropod dinosaur Dreadnoughtus schrani

A chasmosaurine ceratopsid premaxilla from the basal sandstone of the Hell Creek Formation, Montana

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