Dinosaur Skeletons Research Articles

Imagining Dinosaurs

Abstract There is a tendency to take mounted dinosaur skeletons at face value, as the raw data on which the science of paleontology is founded. But the truth is that mounted dinosaur skeletons are substantially intention-dependent—they are artifacts. More importantly, I argue, they are also substantially imagination-dependent: their production is substantially causally reliant on preparators’ creative imaginations, and their proper reception is predicated on audiences’ recreative imaginations. My main goal here is to show that dinosaur skeletal mounts are plausible candidates for art-status. But, what is more, I think they are artworks—specifically, sculptures.

First record of abelisaurid theropods and a peirosaurid crocodyliform from the Upper Cretaceous of Precordillera of La Rioja, NW Argentina

Extra-Patagonian records of Cretaceous theropod dinosaurs in Argentina are limited. When it comes to the Northwest of Argentina, most of the records come from the Cretaceous rocks of Salta Province, which yielded ceratosaurian abelisauroids like Noasaurus and Guemesia. Preliminary studies of the Los Llanos Formation at Eastern La Rioja Province recognized bone remains of Upper Cretaceous undetermined Abelisauridae and Coelurosauria. Recent surveys in the Northwest of the same province, in the outcrops of the Upper Cretaceous Ciénaga del Río Huaco Formation, at Quebrada Santo Domingo (Precordillera), resulted in the discovery of six isolated shed tooth crowns of putative abelisaurid theropods and crocodyliforms. They were found in association with partial skeletons of titanosaurid sauropod dinosaurs from two quarry sites, in the lower and upper sections of the same unit. Here we corroborate the taxonomic assignment of these specimens and their phylogenetic relationships. Five out of six teeth were assigned to Abelisauridae, whereas the remaining is considered to belong to a peirosaurid crocodyliform. Thus, the first occurrence of abelisaurid theropods and peirosaurid crocodyliforms in the Upper Cretaceous of the Precordillera of La Rioja is confirmed. Even though the teeth cannot be assigned to a less inclusive taxon, the difference in their stratigraphic position might indicate the presence of more than a single abelisaurid species in this region. The new results offer an optimistic perspective for future expeditions in this area, which intend to recover more skeletal elements.

Osteoarthritis.

The clinical appearance and radiological pattern of osteoarthritis have been identified in the skeletons of dinosaurs some 50-70 million years old, and in Egyptian mummies, and in ancient skeletons in England. Osteoarthritis patterns of joint involvement, often referred to as primary osteoarthritis, can be seen in the hands, spinal facet joints, hips, knees and feet, but can also be termed secondary osteoarthritis when seen in any joint that has had trauma, sepsis, surgery or metabolic insult. The prevalence of osteoarthritis increases with age. The histology and pathophysiology both demonstrate an inflammatory process. While there have been studies of genetic predisposition, the basic cause of primary osteoarthritis has not been determined.

Pedal Skeletal Proportions of Bipedal and Potentially Bipedal Dinosaurs and Other Archosaurs: Interpreting the Makers of Early Mesozoic Footprints

Dinosaur footprints often occur in Late Triassic–Early Jurassic continental sedimentary rocks. While many such tracks can readily be associated with the kinds of dinosaurs that made them, the makers of some footprints have been controversial. Large tridactyl (three-toed) footprints of the ichnogenus Eubrontes are thought by most paleontologists to have been made by theropod dinosaurs, but some workers think their makers were basal sauropodomorph (“prosauropod”) dinosaurs. The four-toed footprint Otozoum is usually interpreted as a prosauropod print, but some workers instead attribute it to an ornithischian (basal thyreophoran) dinosaur or even a pseudosuchian archosaur. These issues prompted us to do a new study of the proportions of the hindfeet of bipedal and potentially bipedal dinosaurs and other archosaurs, adding new measurements to previously available data. Foot skeletons of theropod dinosaurs differ from those of bipedal ornithischian dinosaurs in having relatively longer phalanges from the middle portions of toes, narrower phalanges, relatively shorter unguals, and a relatively shorter inner toe (digit I—but some members of both groups lose digit I altogether). Theropod feet differ from feet of prosauropods in having slightly narrower phalanges, relatively shorter unguals, and a relatively shorter digit I, but some smaller basal sauropodomorphs are harder to distinguish from theropods in these features. Feet of small to medium-sized ornithischians that retain digit I are very similar to those of most basal sauropodomorphs and also some pseudosuchians. Our results suggest that most (but perhaps not all) morphologically well-preserved Eubrontes are more likely to have been made by theropods than bipedal sauropodomorphs. It is more difficult to determine the most likely maker(s) of Otozoum.

Walter Georg Kühne (1911-1991) and the discovery of the first semi-articulated titanosaurian sauropod from Europe

ABSTRACT In 1954 Walter Georg Kühne (1911–1991), the renowned discoverer of Mesozoic mammals, explored the south-Pyrenean basins of Catalonia with the aim of finding Cretaceous mammal-bearing sites. As a result, the German palaeontologist discovered one of the most important dinosaur fossils in the history of dinosaur research in Spain. In the Tremp Basin, near Orcau village, he found the remains of a large sauropod dinosaur, but a series of incomprehensible vicissitudes made the find forgotten and its extraction incomplete for over 60 years. Unprecedented research into the history of this discovery, including unpublished documents, images, and field notes, has revealed details on the costs of the campaigns, the daily logistics, the field techniques, and the fossils unearthed in the 1954 and 1955 excavations. More importantly, this new research ascertains that Kühne had already determined that the dinosaur skeleton was articulated from the pelvic girdle onwards. Even without being published, that was a historically significant achievement as, back then, the new specimen became the first and semi-articulated titanosaurian sauropod found in Europe. Currently, the sauropod fossils found by Kühne in Orcau, together with additional appendicular and axial bones, are the holotype of Abditosaurus kuehnei.

Voyage of Ben Cao, Part II: Development of Chinese Medicinal Specimens in the British Museum

Voyage of Ben Cao, Part II: Development of Chinese Medicinal Specimens in the British Museum

Oldest dinosauromorph from South America and the early radiation of dinosaur precursors in Gondwana

Whereas the oldest dinosaur skeletons have been excavated from mid to late Carnian beds of South America, its close relatives occur in Anisian to early Carnian deposits from Argentina, Tanzania and Zambia. These close relative forms are key taxa regarding the investigation of macroevolution of dinosauromorphs. Early dinosaurs are well-documented from Carnian strata of Brazil, whereas the Ladinian deposits lack any unambiguous evidence of dinosauromorphs. Here, we present the first dinosauromorph from the Middle Triassic sediments (Pinheiros-Chiniquá Sequence) of Brazil. The new specimen is a right femur and is from the Dinodontosaurus Assemblage Zone (AZ). This AZ is usually correlated with the Tarjadia AZ from Argentina, which is ascribed to the Ladinian-Carnian boundary and currently lacks any evidence of dinosauromorphs. Therefore, the new specimen is potentially the oldest dinosauromorph from South America, narrowing the biogeographical gap between Africa and Argentina during the early radiation of dinosauromorphs. In addition, the new specimen establishes that dinosauromorphs lived in South America earlier than previously expected, extending the record into the Ladinian.

A Juvenile Specimen of Sauropodomorpha from the Lower Jurassic of China and a Brief Review of the Lufeng Sauropodomorph Fauna

AbstractAn incomplete dinosaur skeleton, including a partial skull, recently discovered from the Lower Jurassic Lufeng Formation of Yunnan, China, is here reported. Apart from its small size, little anatomical evidence supports, a priori, the non‐adult status of this new sauropodomorph specimen but osteohistological analyses suggest that it is a fast‐growing juvenile. This specimen represents only the second occurrence of a juvenile non‐sauropodan sauropodomorph in the Lufeng Basin. The anatomy of the new specimen does not match that of other Lower Jurassic immature specimens; although cranial material is preserved, it does not display the diagnostic characters of early sauropodomorphs from the same horizon, namely Lufengosaurus, Yizhousaurus and Yunnanosaurus. Our phylogenetic analysis places the new specimen in a position relatively distant from other Chinese sauropodomorphs, and corroborates the anatomical evidence showing it is not referable to any known species already excavated in Yunnan. This result is interpreted with caution considering that ontogeny affects phylogenetic reconstruction. A thorough comparison with adult forms, taking into account ontogeny‐related characters, suggests that this Lufeng juvenile might represent a previously unknown species of early sauropodomorph.

Paleontology vs. Archaeology in the French Riviera volcanism : crystallized Permian animals and dinosaur skeletons in andesitic rocks, and human remains from the medieval times

This letter details principles of fossilization that matter for the study of fossils in general, but with a preference for sites next to volcanic areas.

Reconstructing the Specimens and History of Howe Quarry (Upper Jurassic Morrison Formation; Wyoming)

In 1934, Barnum Brown of the American Museum of Natural History in New York (AMNH) led a large-scale dinosaur excavation in northern Wyoming, where he had found bones two years earlier. Initially, Brown expected to excavate two skeletons of sauropod dinosaurs, but soon after opening the quarry, the team realized that the site far exceeded their expectations: in the end, they unearthed approximately 3000 bones within six months and sent approximately 144 crates back to the AMNH. Due to the enormous number of bones, the site became world famous as a dinosaur graveyard, and media from all over the United States and abroad reported on the expedition. Soon after, however, the collection shifted away from a curatorial focus. What followed was a history of neglect: inappropriate storage conditions, water and fire damage, collapsing wooden boxes, and deteriorating plaster jackets.Relocation and further excavation of the quarry by the Sauriermuseum Aathal (Switzerland; SMA) from 1989 to 1991 confirmed earlier finds of skin impressions and resulted in the recognition of a novel diplodocid sauropod: Kaatedocus siberi. Given that the amount of bones found by the AMNH far exceeded those found by the SMA, a new project was started in 2017 to reassess the state and scientific value of the historic collections at AMNH. Although most of the bones are heavily fragmented, preliminary results show that overall preservation is still exceptional. Here, we reconstruct the history of the excavation, as well as past conservation and preparation procedures, and provide a report of current efforts to prepare, conserve, and catalog the material that has remained in storage since the 1930s. These current efforts show that historic collections, even after decades of neglect, can be of great and unexpected value, both for research and scientific outreach.

Cretaceous flora and fauna of the Sustut Group near the Sustut River, northern British Columbia, Canada

A partial ornithischian dinosaur skeleton discovered near the Sustut River in 1971 has, to date, represented the only vertebrate fossil remains recovered from the Sustut Basin in northern British Columbia, Canada, but the geological provenance and age of this specimen has remained unclear. We provide new data on the age of this dinosaur specimen based on reconnaissance palaeontological prospecting along the Sustut River, and also report new vertebrate and plant fossils from this region. A skeletal fragment of a species of the turtle Basilemys Hay, 1902 was discovered at a site closely matching field notes describing the initial collection of the ornithischian dinosaur, suggesting that the new turtle fossil derives from the same locality as the dinosaur. Palynomorphs collected from this site include the marker taxon Pseudoaquilapollenites bertillonites (Sriv.), found in the lower Hell Creek Formation, and suggesting an age range of between 68.2 and 67.2 Ma for the locality. To the west of this locality we discovered multiple new fossil plant sites preserving wood and the leaves of Metasequoia Miki and several angiosperms, and one site preserved fronds resembling a species of the tree fern Coniopteris Brong., suggesting a Cenomanian or older age for sites in the area. The complex translational history of the Intermontane Terrane means that the newly discovered turtle may not represent a northern range extension for Basilemys, but it does represent one of the westernmost occurrences of this genus. The discovery of new vertebrate fossil remains in a region with relatively little accessible outcrop at present indicates the potential for future discoveries in the higher elevation outcrops of the Sustut Basin in this mountainous region of British Columbia.

A New View of the Mass Extinctions and the Worldwide Floods

In this study, the reasons for mass extinction in Jurassic were investigated. It was shown that galactic compression led to the activation of terrestrial nuclear reactors, which in turn led to the changes in tectonic activity, volcano eruptions, LIPs, MORBs, paleoclimate change, drift of continents, narrowing of the Earth, worldwide floods, tsunami, changes in mantle and core structures, in magnetic fields and in sedimentary isotopes. It was shown that the mass extinctions occurred during worldwide floods, caused by the narrowing of the Earth at the time of galactic gravitational compression. It was shown that the average statistical altitude distribution of dinosaurs has a bimodal distribution and corresponds to permanent migrations between the plains and the hills. It has been suggested that the skeletons of dinosaurs are well preserved as a result of covering the bodies of dinosaurs with mud flows of coastal sediments and the soil layers at worldwide tsunami. It was formulated the requirement to paleontology, consisting in the obligatory registration of altitudes of the actual place of the fossils found. The simple explanation of the presence of boundaries in the structure of the Earth is given: the 40K nuclear layer corresponds to the boundary between upper and lower mantle; the 137Cs layer located on the boundary between the lower mantle and the outer core; the Th-U nuclear layer is a border between outer and inner core. The previously abstract theories of subduction and continents drift have a clear and obvious physical sense. It was shown that the standard geological table is a registration book of galactic events during Paleozoic. It is proposed to restore the structure of the galactic arms by the geological deposits on the Earth. It was suggested to create the stations on elevated hills for rescue and regeneration of biological forms in the future.

A new leptoceratopsid dinosaur from Maastrichtian-aged deposits of the Sustut Basin, northern British Columbia, Canada.

A partial dinosaur skeleton from the Sustut Basin of northern British Columbia, Canada, previously described as an indeterminate neornithischian, is here reinterpreted as a leptoceratopsid ceratopsian, Ferrisaurus sustutensis, gen. et. sp. nov. The skeleton includes parts of the pectoral girdles, left forelimb, left hindlimb, and right pes. It can be distinguished from other named leptoceratopsids based on the proportions of the ulna and pedal phalanges. This is the first unique dinosaur species reported from British Columbia, and can be placed within a reasonably resolved phylogenetic context, with Ferrisaurus recovered as more closely related to Leptoceratops than Montanoceratops. At 68.2–67.2 Ma in age, Ferrisaurus falls between, and slightly overlaps with, both Montanoceratops and Leptoceratops, and represents a western range extension for Laramidian leptoceratopsids.

An exceptionally preserved association of complete dinosaur skeletons reveals the oldest long-necked sauropodomorphs.

The rise of sauropodomorphs is still poorly understood due to the scarcity of well-preserved fossils in early Norian rocks. Here, we present an association of complete and exceptionally well-preserved dinosaur skeletons that helps fill that gap. They represent a new species, which is recovered as a member of a clade solely composed of Gondwanan Triassic taxa. The new species allows the definition of a set of anatomical changes that shaped sauropodomorph evolution along a period from 233 to 225 Ma, as recorded in the well dated Late Triassic beds of Brazil. In that time span, apart from achieving a more herbivorous diet, sauropodomorph dinosaurs increased their size in a ratio of 230% and their typical long neck was also established, becoming proportionally twice longer than those of basal taxa. Indeed, the new dinosaur is the oldest-known sauropodomorph with such an elongated neck, suggesting that the ability to feed on high vegetation was a key trait achieved along the early Norian. Finally, the clustered preservation mode of the skeletons represents the oldest evidence of gregarious behaviour among sauropodomorphs.

Collector's item or cultural heritage? The Dinosaur Artist: Obsession, Betrayal, and the Quest for Earth's Ultimate Trophy Paige Williams Hachette Books, 2018. 432 pp.

A riveting tale of a smuggled dinosaur illuminates an enduring tension in paleontology

A new sauropodiform dinosaur with a \u2018sauropodan\u2019 skull from the Lower Jurassic Lufeng Formation of Yunnan Province, China

The Early Jurassic Lufeng Formation of Yunnan Province in southwestern China is one of the best fossil localities in the world for understanding the early radiation of sauropodomorph dinosaurs. It has yielded a rich assemblage of complete and three-dimensionally preserved skeletons of herbivorous dinosaurs that provide crucial morphological information for systematic and evolutionary studies. Here we describe a new taxon, Yizhousaurus sunae gen. et sp. nov., represented by a nearly complete skeleton with an exquisitely preserved skull and mandible. Yizhousaurus is distinguished from other non-sauropodan sauropodomorphs by a unique combination of plesiomorphic and apomorphic features, which increases our understanding of the anatomical variation on the relatively conservative ‘prosauropod’ cranial plan. Phylogenetic analysis resolves Yizhousaurus as a sauropodiform, showcasing a mosaic character suite combining plesiomorphic states in the postcranial skeleton with some more ‘sauropodan’-like features in the skull. Furthermore, Yizhousaurus is placed closer to the base of Sauropoda than other non-sauropodan sauropodomorphs currently known from the Lufeng Formation, adding another taxon to enrich the Lower Jurassic Lufeng dinosaur fauna.

A new alvarezsaurid dinosaur from the Late Cretaceous Qiupa Formation of Luanchuan, Henan Province, central China

ABSTRACT An alvarezsaurid dinosaur skeleton was discovered from the Late Cretaceous Qiupa Formation of Luanchuan, Henan Province of central China. It represents a new alvarezsaurid dinosaur Qiupanykus zhangi gen. et sp. nov. A phylogenetic analysis recovers Qiupanykus nested within the unresolved clade, which includes Asian and north American taxa. The skeleton of the new specimen is preserved in association with eggshells. The eggshell morphologies show that these eggs belong to oviraptorid eggs, skeletal remains of which were discovered from the same area. The alvarezsaurid skeleton associated with eggshell fragments may indicate that these eggs were broken by the strong thumb-claws of the former and that alvarezsaurid dinosaurs may be egg-eaters.

A nestling-sized skeleton of Edmontosaurus (Ornithischia, Hadrosauridae) from the Hell Creek Formation of northeastern Montana, U.S.A., with an analysis of ontogenetic limb allometry

ABSTRACTThe Hell Creek Formation preserves one of the most intensely studied late Cretaceous terrestrial fossil units. Over 22 dinosaur genera are currently recognized from this unit, but the record of juvenile individuals is surprisingly limited. Here, we document a nestling hadrosaur that represents the first occurrence of an articulated nestling dinosaur skeleton from the latest Cretaceous (late Maastrichtian) of North America. The specimen (UCMP 128181) preserves a partial scapula, nearly complete rib cage, vertebral series from the shoulder to mid-tail, a large portion of the pelvic girdle, and both hind limbs through a combination of bone and/or natural impressions in the concretion. It is assignable to the genus Edmontosaurus based on the shape of the prepubic process, or blade, of the pubis. The specimen represents the earliest ontogenetic growth stage of Edmontosaurus cf. annectens and possesses a femur length of 148 mm. It greatly contributes as a new end member to a sample of associated Edmontosaurus skeletons that is well suited for allometrically testing the hypothesized ontogenetic gait shift in hadrosaurs from bipedal juveniles to quadrupedal adults using individual limb proportions. Although UCMP 128181 does not preserve forelimbs, regressions based on associated Edmontosaurus skeletons (N = 25) reveal overall isometry of the forelimb relative to the hind limb, and within each limb. These data indicate that Edmontosaurus nestlings were anatomically capable of fully quadrupedal locomotion and provide no compelling evidence to support an ontogenetic gait shift in hadrosaurids.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVPCitation for this article: Wosik, M., M. B. Goodwin, and D. C. Evans. 2018. A nestling-sized skeleton of Edmontosaurus (Ornithischia, Hadrosauridae) from the Hell Creek Formation of northeastern Montana, U.S.A., with an analysis of ontogenetic limb allometry. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1398168.

Forelimb Posture in Chilesaurus diegosuarezi (Dinosauria, Theropoda) and Its Behavioral and Phylogenetic Implications

Many dinosaur skeletons show evidence of behavior, including feeding, predation, nesting, and parental care. The resting posture of the forelimbs has been studied in some theropod species, in relation to the acquisition of flight in advanced maniraptoran theropods. Chilesaurus diegosuarezi is a bizarre tetanuran recently described from the Toqui Formation (latest Tithonian) of southern Chile that is represented by multiple well-preserved and articulated specimens. The aim of the present work is to analyze the forelimb posture of four articulated specimens of Chilesaurus diegosuarezi, focusing on its anatomical description, and phylogenetic and behavioral implications. All the preserved specimens show strongly ventrally flexed arms with the hands oriented backwards, an arrangement that closely resembles those in dinosaur specimens previously described as preserving resting posture, such as Mei long, Sinornithoides youngi and Albinykus baatar. As a result, it seems that individuals of Chilesaurus diegosuarezi have been in passive activity (e.g. feeding, resting) when they were buried quickly, allowing their fossilization in life position and preserving the forelimb resting posture. The arrangement of the forelimb bones in Chilesaurus could show the first evidences of the structures linked to the muscles that flex the forearms, features related with the acquisition of flying control in advanced maniraptorans.

Dinosaur tracks at the Nemegt locality: Paleobiological and paleoenvironmental implications

The Nemegt locality is one of the most famous dinosaur localities in Mongolia ever since the site was discovered in 1946. It yields abundant dinosaur skeletons; however, little attention had been given to dinosaur footprints at the locality. The only Nemegt dinosaur footprint study focused on descriptions of the footprints, gave only a few taxonomic implications, and provided no comparison with other dinosaur tracksites. This study reports newly recorded dinosaur footprints (hadrosaurs, sauropods, and theropods) at the Nemegt locality during the Nemegt Educational Expedition of 2016. A single footprint-bearing horizon that extends several kilometres was examined within the Nemegt Formation to determine the ichno-taxonomic assemblage of the Nemegt dinosaurs. A significant difference was identified between taxonomic compositions based on skeletal remains and ichno-taxonomic compositions based on footprints. Although the vast majority of the skeletal elements collected in the area belong to theropods, the footprints suggest that the Nemegt locality was dominated by herbivorous dinosaurs. This suggests that the previously inferred Tarbosaurus dominant taxonomic composition at the Nemegt locality is a result of a preservational bias. The size distribution of the newly studied footprints suggest that the Nemegt hadrosaurs had an adult-dominant and multigenerational population structure. Comparisons with dinosaur tracksites at the Cantwell (Alaska, USA) and Tremp (Spain) formations show that the population structure and body sizes of the Nemegt hadrosaurs were similar to those of the high-latitude Cantwell hadrosaurs. It suggests that the Nemegt area was more open and had higher plant productivity than the Tremp area.