Search results for "Dinosaur"

Preliminary analysis of osteocyte lacunar density in long bones of tetrapods: all measures are bigger in sauropod dinosaurs.

2013

Osteocytes harbour much potential for paleobiological studies. Synchrotron radiation and spectroscopic analyses are providing fascinating data on osteocyte density, size and orientation in fossil taxa. However, such studies may be costly and time consuming. Here we describe an uncomplicated and inexpensive method to measure osteocyte lacunar densities in bone thin sections. We report on cell lacunar densities in the long bones of various extant and extinct tetrapods, with a focus on sauropodomorph dinosaurs, and how lacunar densities can help us understand bone formation rates in the iconic sauropod dinosaurs. Ordinary least square and phylogenetic generalized least square regressions sugge…

Developments and contributions in the study of La Rioja dinosaur footprints (Spain)

2020

In this paper the study of dinosaur tracks of La Rioja, which began in 1970, is presented as an example of knowledge development, achievements, and events occurring around a paleontological resource having strong media impact. Fieldwork, research, and dissemination since the publication of the first scientific works have been accompanied by activities to protect sites and consider them as natural and cultural heritage. Finally it is shown how a paleontological resource has also led to the development of the tourist infrastructure in the area

Reproductive Biology and Its Impact on Body Size: Comparative Analysis of Mammalian, Avian and Dinosaurian Reproduction

2011

Janis and Carrano (1992) suggested that large dinosaurs might have faced a lower risk of extinction under ecological changes than similar-sized mammals because large dinosaurs had a higher potential reproductive output than similar-sized mammals (JC hypothesis). First, we tested the assumption underlying the JC hypothesis. We therefore analysed the potential reproductive output (reflected in clutch/litter size and annual offspring number) of extant terrestrial mammals and birds (as "dinosaur analogs") and of extinct dinosaurs. With the exception of rodents, the differences in the reproductive output of similar-sized birds and mammals proposed by Janis and Carrano (1992) existed even at the …

New insights into non-avian dinosaur reproduction and their evolutionary and ecological implications: linking fossil evidence to allometries of extan…

2013

It has been hypothesized that a high reproductive output contributes to the unique gigantism in large dinosaur taxa. In order to infer more information on dinosaur reproduction, we established allometries between body mass and different reproductive traits (egg mass, clutch mass, annual clutch mass) for extant phylogenetic brackets (birds, crocodiles and tortoises) of extinct non-avian dinosaurs. Allometries were applied to nine non-avian dinosaur taxa (theropods, hadrosaurs, and sauropodomorphs) for which fossil estimates on relevant traits are currently available. We found that the reproductive traits of most dinosaurs conformed to similar-sized or scaled-up extant reptiles or birds. The …

Isotopic ordering in eggshells reflects body temperatures and suggests differing thermophysiology in two Cretaceous dinosaurs

2015

International audience; Our understanding of the evolutionary transitions leading to the modern endothermic state of birds and mammals is incomplete, partly because tools available to study the thermo-physiology of extinct vertebrates are limited. Here we show that clumped isotope analysis of eggshells can be used to determine body temperatures of females during periods of ovulation. Late Cretaceous titanosaurid eggshells yield temperatures similar to large modern endo-therms. In contrast, oviraptorid eggshells yield temperatures lower than most modern endotherms but B6 °C higher than co-occurring abiogenic carbonates, implying that this taxon did not have thermoregulation comparable to mod…

Reconstruction of the internal structure of the pore system of a complex dinosaur eggshell (Megaloolithus siruguei)

2013

Despite the many reconstructions of fossil material that have recently appeared in the literature, dinosaur eggshells have never been reconstructed using computing techniques. Using the EMAC 3-D modelling methodology, we reconstruct a section of the Late Cretaceous Megaloolithus siruguei eggshell, which has a particularly complex pore system, exhibiting an intricate network of vertical, oblique, and horizontal pores.

Dinosauroid footprints of French Upper Triassic. Discrimination, interpretation and comparison

2005

Abstract Dinosauroid tracks are common in France. They are mainly tridactyl II–IV feet tracks, sometimes with those of hands. A lot of these latter Coelurosaurichnus grancieri Courel & Demathieu, 2000 was discovered by MG near the village of Payzac (Ardèche department) in beds belonging to the “Ensemble gréso-dolomitique gris” (= EGDG) (fig. 1. 2). They are dated Carnian from palynological data [Fauconnier et al., 1996]. C. grancieri are tracks of feet and hands respectively 10 cm and 2.5 cm long (fig. 1. 3–5, 7–21; tabl. I-1, tabl. II). From the trackways characters, it was inferred that trackmakers were long legged, bipedal-quadrupedal reptiles, 1–2 m long. New discoveries made by M…

Recensione di CAU A., 2019. La rivoluzione piumata. I nuovi dinosauri e l’origine degli uccelli. Volume primo, Pubblicazione indipendente, 160 pp.,13…

2021

A possible bridge between Adria and Africa: New palaeobiogeographic and stratigraphic constraints on the Mesozoic palaeogeography of the Central Medi…

2010

Abstract Dinosaur records in central and southern Italy testify to the occurrence of a diverse dinosaur fauna on the Apennine and Apulian carbonate platforms at least from the Tithonian to the Santonian. Most of the palaeogeographic reconstructions show these domains as topographically isolated areas, separated by deep pelagic basins and far from emerged continental areas. Thus, they hardly justify the long-lasting occurrence of these terrestrial vertebrates. Recent studies on the Mesozoic Panormide Carbonate Platform (western Sicily) yielded important stratigraphical and palaeontological data, which provide evidence for a convincing explanation of this unresolved problem. The recent discov…

Dinosaur bonebed amber from an original swamp forest soil

2021

AbstractDinosaur bonebeds with amber content, yet scarce, offer a superior wealth and quality of data on ancient terrestrial ecosystems. However, the preserved palaeodiversity and/or taphonomic characteristics of these exceptional localities had hitherto limited their palaeobiological potential. Here we describe the amber from the Lower Cretaceous dinosaur bonebed of Ariño (Teruel, Spain) using a multidisciplinary approach. Amber is found in both a root layer with amber strictly in situ and a litter layer namely composed of aerial pieces unusually rich in bioinclusions, encompassing 11 insect orders, arachnids, and a few plant and vertebrate remains, including a feather. Additional palaeont…