Dinosaur Paleontology

Oryctodromeus is a small bipedal dinosaur known from middle Cretaceous (95-100 My) Wayan Formation of Idaho and the Vaughn Member of the Blackleaf Formation of Montana. This taxon is hypothesized to be a burrowing dinosaur, which cared for its young within these burrows. This dissertation is a broad three-part treatment of this taxon, and excepting the introductory and concluding chapters this dissertation consists of three main chapters. Chapter two describes the osteology and phylogenetic relationships of this animal. Notable features of the Oryctodromeus skeleton described include a network of ossified tendons along the vertebral column that completely ensheath the tail, a long tail that forms more than half the length of the animal, and unusual femoral heads whose morphology may be related to burrowing behavior. The first full skeletal and skull reconstructions of this animal are presented. Chapter three investigates patterns of preservation of Oryctodromeus. Data suggests that preservation of single to multiple individuals of this taxon typically occurred in burrows that may be difficult to impossible to recognize in the fossil record. New examples of burrows from Oryctodromeus from the Vaughn and Wayan, as well as additional evidence for social behavior, are also described. A third chapter details the ontogenetic histology, growth rates and patterns of skeletal fusion based on seven limb elements (femora and tibiae) from different individuals. Based on the data in this dissertation, three growth stages can be recognized in Oryctodromeus based on bone histology. Juveniles are defined by more rapidly growing fibrolamellar tissue, sub-adults are defined by a cortex of inner fibrolamellar tissue and outer zonal parallel fibered tissue, and near-adult individuals have tissue similar to sub adults with dense avascular bone in the outermost cortex that signals a decrease in growth rate. LAG’s suggest a minimum age of six to seven years for more mature individuals. Patterns of neurocentral fusion in Oryctodromeus appear similar to those of crocodylians and some other small ornithischians, while the growth rates of Oryctodromeus appear slower than those of some dinosaurs, but similar to taxa such as Orodromeus and Tenontosaurus.

El Centro Regional de Formación del Profesorado (CRFP) de Castilla-La Mancha ha organizado un proyecto en el que unos doscientos estudiantes de diferentes etapas (colegio, instituto, educación especial y universidad) han protagonizado un vídeo musical interpretando una canción original compuesta para la ocasión. Así y bajo el nombre de ‘Concavenator Corcovatus’, el objetivo principal de la propuesta es difundir el Museo Paleontológico de Castilla-La Mancha (MUPA y, sobre todo, a un dinosaurio conquense muy especial, único en el mundo, conocido cariñosamente como Pepito.

A census of Hell Creek and Lance Formation dinosaur remains was conducted from April, 2017 through February of 2018. Online databases were reviewed and curators and collections managers interviewed in an effort to determine how much material had been collected over the past 130+ years of exploration. The results of this new census has led to numerous observations regarding the quantity, quality, and locations of the total collection, as well as ancillary data on the faunal diversity and density of Late Cretaceous dinosaur populations. By reviewing the available data, it was also possible to make general observations regarding the current state of certain exploration programs, the nature of collection bias present in those collections and the availability of today's online databases.

A total of 653 distinct, associated and/or articulated remains (skulls and partial skeletons) were located. Ceratopsid skulls and partial skeletons (mostly identified as Triceratops) were the most numerous, tallying over 335+ specimens. Hadrosaurids (Edmontosaurus) were second with at least 149 associated and/or articulated remains. Tyrannosaurids (Tyrannosaurus and Nanotyrannus) were third with a total of 71 associated and/or articulated specimens currently known to exist. Basal ornithopods (Thescelosaurus) were also well represented by at least 42 known associated and/or articulated remains. The remaining associated and/or articulated specimens, included pachycephalosaurids (18), ankylosaurids (6) nodosaurids (6), ornithomimids (13), oviraptorosaurids (9), dromaeosaurids (1) and troodontids (1).
Over 41,800 isolated bones and teeth, were also located. This number represents only a small fraction of the actual total collection as many of the museums and institutions surveyed were unable to provide complete numbers on isolated elements. Over 46% of these isolated bones and teeth were identified as hadrosauridae, usually identified as Edmontosaurus. Isolated elements identified as ceratopsids made up just over 21% of the total. These were generally identified as Triceratops. Isolated bones and teeth of tyrannosaurids were significantly less, at only 4.6%. The large difference between the associated and/or articulated remains and the isolated bones and teeth of tyrannosaurids (10.9% down to 4.6%) and ceratopsids (51.3% to 21.5%) is likely due to both a preservational and collection bias towards the larger, more likely to be fossilized, and more likely to be collected, Tyrannosaurus and Triceratops skeletons and skulls.

Even though small theropods accounted for less than 0.6% of the total recovered associated and/or articulated remains, their teeth and isolated elements were encountered quite frequently. Isolated bones and teeth of dromaeosaurids, troodontids and “unidentified small theropods” accounted for as much as 16% of the total number of isolated remains. This data suggests that there is a tremendous level of collection and preservational bias in the current Hell Creek and Lance sample set Actual small theropod diversity and populations in the Late Cretaceous were most likely much higher than previously considered.
It is highly likely that the fluvial and geochemical environment that dominated the Late Cretaceous of this region was simply too rough and tumble for bones of most genera under the 400 kg live weight

The Journal of Paleontological Sciences: JPS.C.2019.01 2
threshold to be preserved. Both preservational bias and collection bias appear to play significant roles in how we currently view the diversity of the Hell Creek and the Lance. This has directly influenced our perception of the end Cretaceous extinction event. It is entirely possible that many genera will never be known from more than fragmentary remains.

The Arabian fossil potential had been largely unexplored until the last two decades. Although its fossil record has improved considerably in terms of quantity, it still largely consists of poorly preserved undiagnostic material. Here we describe a newly discovered enigmatic ornithopod braincase from the Al-Khod Conglomerate Formation of Oman. This formation fills an important spatio-temporal gap, given its position in between Africa and Eurasia, its long palaeogeographic relationship with Africa and being latest Cretaceous (post-Cenomanian) in age. It has produced one of the most taxonomically diverse latest Cretaceous faunas for any Gondwanan landmass and a significant portion of all dinosaur records from the Arabian Peninsula. The braincase is assigned to Ornithopoda on the basis of: a U-shaped occipital condyle, the dorsoventral proportions of the posterior braincase and the angle of the exoccipital-supraoccipital contact. Unlike typical ornithopods it displays short and laterally restricted basipterygoids, prominent basal tuberi and a narrow dorsal skull margin. Endocranial features including a very narrow and steep median ridge, the inner ear morphology and the hypoglossal arrangement are more typical of ornithopods. A unique combination of features, most notably: the separate canal for the ophthalmic branch of the trigeminal nerve (CN V), the large fossa above the cerebral carotid foramen, and an almost total absence of a floccular recess, justify an identification as a non-hadrosaurid ornithopod. The presence of various (generally small-sized) ornithopod lineages combined with peculiar morphologies in the Al-Khod vertebrate fauna paradoxically hints at periodic isolation and potentially trans-Tethys faunal connectivity between Afro-Arabia and Eurasia.

Late Cretaceous-Early Paleocene Deccan Volcanic Flood Basalt occupying an area of about 500,000 km2 in peninsular India. The Lameta sediments of Late Cretaceous covered the six inland basins viz. Nand Dongargaon (N-D); Jabalpur; Sagar; Ambikapur- Amarkantak; Balasinor Jhabua and Salbardi-Belkher in the states of Maharashtra, Madhya Pradesh and Gujarat of Central India. The detail palynology and clay mineralogy is carried out of sediments of Nand-Dongargaon and Salbardi-Belkher inland basins during present study. Lithologically, Lameta sediments comprises of limestone, red and green clay, marlite and calcareous sandstone. The palynoflora from the Lameta sediments and sauropod dinosaur coprolites is represented by gymnosperms (Araucariacites sp., Cycadopites sp., Podocarpidites sp., Classopollis sp., etc), angiosperms (Palmaepollenites sp., Longapertites sp., Graminidites sp., Compositoipollenites, Multiareolites, Tetracolporate and Polycolporate pollen, etc.) and pteridophytes (Azolla massulae, Cyathidites, trilete spores, etc.). Presence of good preservation of three genera of thecamoebians viz. Centropyxis, Difflugia and Pontigulasia, grass phytoliths of Poaceae, starch cells, peltate hairs, fungi and other plant remains like leaf cuticles, starch cells and tracheal material. Other biota like fungal spore (Monocellate, Dicellate and Multicellate), algal (Botryococcus, Oedogonium) and bacterial remains associated with diatom frustules (Aulacoseira), invertebrates like gastropods and bivalves have also been recovered. However, many intertrappean beds have been studied from the study area and lithologically they comprises mostly of cherty limestone with nodular structure, highly fossiliferous dark green/ black grey chert, shales, shaly chert, tuffaceous breccias, green clay and white clay, sandy shales and occasional calcareous sandstone. The biotic assemblage of intertrappean beds consists of freshwater Maastrichtian age marker palynoflora viz. Jiangsupollis, Farabeipollis, Aquilapollenites bengalensis, Gabonisporis vigaurouxii, Gabonisporites, Azolla. Microfauna such as Foraminiferal linings, peridinium dinoflagellate and other organic structures, Gastropods (Physa, Lymnia, Turittela and Viviforms) and Ostracods (Mongolianella, Cypridopsis, Frambocythere and Paracypretta, etc) have also been
recovered. Apart from Palynoflora, megafloral remains represented by palm roots, fossil woods of both dicots and monocots, well preserved fruits of angiosperm plants are also present in intertrappean beds of the study area. Palynology from coprolites of N-D basinsuggests sauropod dinosaurs preferred to ate soft tissues of angiosperms and gymnosperms. The presence of phytoliths of Poaceae indicates diversity of grasses during the Maastrichtian period. Sauropod dinosaurs ingested thecamoebians, burnt grasses, sponge spicules, diatoms,
fungal spores, mycorrhizal fungi and other plant tissues during intake of water. Lithology, Palynoflora and Clay mineralogy from the study area suggests prevalence of Arid to Semiarid climate with marked seasonality, lacustrine environments and prevailing sub-humid condition at the time of deposition of the intertrappean beds. The study helped
in understanding the deposition and recording Palynoflora and microfauna, environmental condition from the Lameta and Intertrappean sediments, floral changes with the volcanic activity in the Nand-Dongargaon and Salbardi-Belkher inland basin as well as climate during
Late Cretaceous-Early Paleocene.

Keywords: Sauropod dinosaurs, coprolites, Palynoflora, Microfauna, Maastrichtian, Intertrappeans, Inland basins, Deccan Volcanic Flood Basalt, Central India.

Dinosaurs were ubiquitous in terrestrial ecosystems through most of the Mesozoic and are still diversely represented in the modern fauna in the form of birds. Recent efforts to better understand the origins of the group have resulted in the discovery of many new species of early dinosaur and their closest relatives (dinosauro-morphs). In addition, recent re-examinations of early dinosaur phylogeny have highlighted uncertainties regarding the interrelationships of the main dinosaur lineages (Sauropodomorpha, Theropoda and Ornithischia), and questioned the traditional hypothesis that the group originated in South Gondwana and gradually dispersed over Pangaea. Here, we use an historical approach to examine the impact of new fossil discoveries and changing phylo-genetic hypotheses on biogeographical scenarios for dinosaur origins over 20 years of research time, and analyse the results in the light of different fossil record sampling regimes. Our results consistently optimize South Gondwana as the ancestral area for Dinosauria, as well as for more inclusive clades including Dinosauromorpha, and show that this hypothesis is robust to increased taxonomic and geographic sampling and divergent phylogenetic results. Our results do not find any support for the recently proposed Laurasian origin of dinosaurs and suggest that a southern Gondwanan origin is by far the most plausible given our current knowledge of the diversity of early dinosaurs and non-dinosaurian dinosauromorphs.

Ever wanted to travel around the world? Well, the Wildlife of Gondwana exhibition certainly has! After 20 years of captivating and educating people about the many millions of years of Australia’s unique fauna and flora, this exhibition will find its final home in the Australian Age of Dinosaurs (AAOD) Museum of Natural History in Winton, Queensland.

Birds are the only living amniotes with coloured eggs 1–4 , which have long been considered to be an avian innovation 1,3. A recent study has demonstrated the presence of both red-brown protoporphyrin IX and blue-green biliverdin 5 —the pigments responsible for all the variation in avian egg colour—in fossilized eggshell of a nonavian dinosaur 6. This raises the fundamental question of whether modern birds inherited egg colour from their nonavian dinosaur ancestors, or whether egg colour evolved independently multiple times. Here we present a phylogenetic assessment of egg colour in nonavian dinosaurs. We applied high-resolution Raman microspectroscopy to eggshells that represent all of the major clades of dinosaurs, and found that egg colour pigments were preserved in all eumaniraptorans: egg colour had a single evolutionary origin in nonavian theropod dinosaurs. The absence of colour in ornithischian and sauropod eggs represents a true signal rather than a taphonomic artefact. Pigment surface maps revealed that nonavian eumaniraptoran eggs were spotted and speckled, and colour pattern diversity in these eggs approaches that in extant birds, which indicates that reproductive behaviours in nonavian dinosaurs were far more complex than previously known 3. Depth profiles demonstrated identical mechanisms of pigment deposition in nonavian and avian dinosaur eggs. Birds were not the first amniotes to produce coloured eggs: as with many other characteristics 7,8 this is an attribute that evolved deep within the dinosaur tree and long before the spectacular radiation of modern birds.

During their long evolutionary history, neornithischian dinosaurs diverged into several clades with distinctive adaptations. However, the early evolution within Neornithischia and the resolution of the phylogenetic relationships of taxa situated near the base of the clade remain problematic. This is especially true for those taxa traditionally placed at the base of Ornithopoda, either as 'hypsilophodontids' or at the base of the diverse clade Iguanodontia. Recent studies are improving our understanding of the anatomy and relationships of these taxa, with discoveries of several new non-ankylopollexian ornithopods from South America and Europe providing key insights into early ornithopod evolution and palaeobiogeography. Here, we describe a new basal ornithopod, Burianosaurus augustai gen. et sp. nov., based on a well-preserved femur from the upper Cenomanian strata (Korycany Beds of the Peruc-Korycany Formation) of the Czech Republic. The new taxon is diagnosed by a unique suite of characters and represents the only occurrence of a Cenomanian non-avian dinosaur in Central Europe north of the Alpine Tethyan areas. Histological examination of the type specimen reveals the presence of a loosely packed Haversian system which suggests relatively mature bone from a possible young adult. Phylogenetic analyses of two different data sets, selected to test the placement of B. augustai in various parts of the neornithischian tree, reconstruct B. augustai as a basal ornithopod, firmly nested outside Ankylopollexia. These results also support a diverse Elasmaria as a basal clade within Ornithopoda and reconstruct Hypsilophodon outside Ornithopoda as the sister taxon to Cerapoda. However, the relationships of 'hypsilophodontids' within Neornithischia remain contentious.

Functional reconstructions of extinct animals represent a crucial step towards understanding palaeocological interactions, selective pressures and macroevolutionary patterns in the fossil record. In recent years, computational approaches have revolutionised the field of 'evolutionary biomechanics' and have, in general, resulted in convergence of quantitative estimates of performance on increasingly narrow ranges for well studied taxa. Studies of body mass and locomotor performance of Tyrannosaurus rex – arguably the most intensively studied extinct animal – typify this pattern, with numerous independent studies predicting similar body masses and maximum locomotor speeds for this animal. In stark contrast to this trend, recent estimates of maximum bite force in T. rex vary considerably (> 50%) despite use of similar quantitative methodologies. Herein we demonstrate that the mechanistic causes of these disparate predictions are indicative of important and underappreciated limiting factors in biomechanical reconstructions of extinct organisms. Detailed comparison of previous models of T. rex bite force reveals that estimations of muscle fibre lengths and architecture are the principal source of disagreement between studies, and therefore that these parameters represents the greatest source of uncertainty in these reconstructions, and potentially therefore extinct animals generally. To address the issue of fibre length and architecture estimation in extinct animals we present data tabulated from the literature of muscle architecture from over 1100 muscles measured in extant terrestrial animals. Application of this dataset in a reanalysis of T. rex bite force emphasises the need for more data on jaw musculature from living carnivorous animals, alongside increased sophistication of modelling approaches. In the latter respect we predict that implementing limits on skeletal loading into musculoskeletal models will narrow predictions for T. rex bite force by excluding higher-end estimates.