Dinosaur Behaviour Research Articles

Palaeoenvironmental reconstruction of dinosaur nesting sites based on a geochemical approach to eggshells and associated palaeosols (Maastrichtian, Provence Basin, France)

Variability of the stable isotopic (δ 13C and δ 18O) and trace element (Mg, Sr, Fe, and Mn) content from dinosaur eggshells from the Provence Basin has been addressed by considering the stratigraphic distribution of the eggshells, the palaeoenvironments, and the chemical content of associated sediments. Preferentially, in situ eggshells were analysed. Samples were collected from two sections, one belonging to the floodplain (Roques Hautes) and the other to the channel belt (Rousset–Bréguières), as determined from sedimentological criteria. On a regional scale, this combined analysis provided new insights into palaeohydrology, vegetation cover and dinosaur behaviour. Different sources of drinking water were identified: (1) the main stream waters with significant salinity levels, (2) lateral feeders with water composition close to that of precipitation. Water composition is reflected in the eggshell trace element contents: a high Sr content for the eggshells from the channel belt (mean 1200 ppm) contrasting with the very low values for the floodplain (mean 250 ppm). During the first part of the Maastrichtian, evaporation rates were quite significant, as seen from the 1.5‰ difference between the eggshell δ 18O (drinking water) and the palaeosol carbonate nodules (precipitation). This contrast diminished and became nearly insignificant in the second half of the Maastrichtian. Vegetation was composed of C 3 plants and two ecosystems are reconstructed: a riparian forest extending along the channel belt and open vegetation in the floodplain. The contrasted isotopic and trace element content of the eggshells was a crucial factor in identifying animal migration from one site to another. Migration was quite limited, suggesting that the animals settled for some time at the places where they laid their eggs. Intraspecific variations among modern birds are well correlated with the environment and may be greater than interspecies variations, which limits the potential of geochemical analysis to characterise dinosaur species.

Lessons from the EPSCoR States

The author is director of the Montana EPSCoR program and professor of Plant Pathology at Montana State University, Bozeman, MT. Federal funds for research are presently targeted for reduction. At the same time, the U.S. scientific community is viewed as detached from the people who pay its bills—Congress, state legislators, and, ultimately, the public. These facts make it apparent that scientists need to more directly involve people at all levels of public leadership in the scientific enterprise. The attitude that “someone else will do it” will no longer suffice. If the enterprise is to remain strong, new methods of acquiring public support for science are needed. A little-recognized program called EPSCoR (Experimental Program to Stimulate Competitive Research), begun by the National Science Foundation (NSF) in 1980, has devised a model that may work for the entire country. The program had its beginnings in Congress9s realization that 18 states (some of the nation9s poorest) and Puerto Rico receive only about 4% of the annual federal RD Quantum Research Corporation (also of Bethesda) gathers quantitative information on the programs of each state. Fundamental scientific discoveries have been made under the auspices of EPSCoR projects. Those discoveries are serving the needs of the states, and some have had national and international impacts. Specific examples are Maw Kuen Wu9s participation in the discovery of high-temperature superconductivity while at the University of Alabama and Jack Horner9s remarkable discoveries at Montana State University concerning dinosaur behavior, which helped inspire the story of Jurassic Park and promote a local dinosaur tourism industry. Overall, EPSCoR has had a nationwide impact by increasing the competitiveness of scientists. This is seen most clearly in the fact that since the program9s inception, the EPSCoR states have doubled their share of NSF funding (not including the funds that NSF specifically allocates to support EPSCoR). Each of the seven major federal agencies that grant funds for research (the National Institutes of Health, U.S. Department of Agriculture, Department of Energy, Department of Defense, Environmental Protection Agency, NASA, and NSF) has now established its own EPSCoR program (although some are more committed than others). The people involved in EPSCoR seem to have devised a system that is well organized and has strong momentum. Its success is the result of a simple formula: research whose value can be justified to the public, carried out by researchers and organizations that take the time to keep the public informed and involved. Our nation9s scientists need to convince all sectors of the public of the importance of basic research. EPSCoR9s successes can teach some important lessons about how to do so.

Juvenile Skeletal Structure and the Reproductive Habits of Dinosaurs

Skeletal ontogeny in extant archosaurians (crocodilians and birds) indicates that the morphology of the perinatal pelvic girdle is an indicator of overall developmental maturity [that is, altriciality (nestbound) versus precociality (mobile and relatively independent)]. Comparison of the skeletal anatomy of perinatal extant archosaurians and perinatal dinosaurs suggests that known dinosaur hatchlings were precocial. These data are consistent with the overall similarity in nesting behavior of dinosaurs and modern crocodilians.

A new oospecies, Megaloolithus matleyi, from the Lameta Formation (Upper Cretaceous) of Chandrapur district, Maharashtra, India, and general remarks on the palaeoenvironment and nesting behaviour of dinosaurs

New occurrences of fossilised eggs of different structural types have been documented from the Upper Cretaceous Lameta Formation of the Chandrapur district of Maharashtra, central India. For the eggshells of tubospherulitic morphotype a new oospecies, Megaloolithus matleyisp. nov., has been established. For the shells of prolatospherulitic and testudoid morphotypes, a general description is given. The eggshells occur in calcretized sandstones that reflect deposition in alluvial-limnic environments under semi-arid conditions. There is evidence for colonial nesting, selection of nesting sites on river-banks, and burial of nests by sauropods.

Dinosaur tracks and other fossil footprints of the western United States

For dinosaur lovers and tourists alike, this guide explores the palaeontological treasure trove of the western United States. Concentrating on the rich fossil life of the Colorado Plateau region - including parts of Utah, Arizona, and New Mexico - it gives readers the story behind a track record which extends some 300 million years back in time. Readers learn about America's prehistory as they explore a region with one of the best track records of land animals found anywhere in the world. An appendix lists museums and other major repositories of tracks and replicas, and gives details on tracksites open to the public. Lockley leads his readers to the footprints themselves, and shows fossil explorers how these traces can help to interpret the behaviour of dinosaurs.

Dinosaur behavior and growth

Geological and paleontological data derived from the Upper Cretaceous Two Medicine Formation of Montana indicates that at least some dinosaur species exhibited complex social behaviors comparable to many living birds. Two species of duck-billed dinosaurs, a hypsilophodontid and a troodontid, nested in colonies and attended their respective young. Duckbilled dinosaurs had altricial young, whereas the hypsilophodontid and troodontid had precocial young. Morphological evidence indicates that several of the cranial elements of the nestling duckbills experienced retarded development, and a retention of juvenile features. Following their respective nesting periods duck-billed and horned dinosaurs aggregated into large herds, and apparently migrated seasonally. Cranial ornamentations possessed by duck-billed and horned dinosaurs were most likely used for sexual display and mate recognition.Osteohistological data indicates that the duck-billed dinosaurs hatched from their eggs at .50 to .75 meters in length, and exited their nests at 1.5 to 2 meters in length, at an age of about one month. These dinosaurs reached 3 to 4 meters in length their first year, and 7 to 8 meters in length after about 5 years. Growth and metabolic rates decreased substantially upon reaching adult size.

Evidence for juvenile groups in the ornithopod dinosaur Tenontosaurus tilletti Ostrom

When the existence of juveniles, eggs, and nesting sites of the hadrosaur Maiasaura peeblesorum and the hypsilophodontid Orodromeus makelai from the Upper Cretaceous Two Medicine Formation of western Montana were reported, they provided powerful insights into the reproductive strategies of these animals (Horner and Makela, 1979; Horner, 1982, 1984; Horner and Weishampel, 1988). Dinosaur eggs had been known since 1923 when nests attributed to the ceratopsian Protoceratops andrewsi were discovered in Mongolia (Brown and Schlaikjer, 1940), but there was no direct information about behavior or survival strategies in hatchling dinosaurs until the Maiasaura and Orodromeus findings. These recent discoveries have generated a number of hypotheses on the reproductive behavior of dinosaurs relating to the extent of parental care, fidelity in nesting sites, and the aggregation of juveniles into groups.

The Nesting Behavior of Dinosaurs

The Nesting Behavior of Dinosaurs