Hypselosaurus is a dubious genus of titanosaurian sauropod that lived in southern France during the Late Cretaceous, approximately 70 million years ago in the early Maastrichtian. Hypselosaurus was first described in 1846, but was not formally named until 1869, when Phillip Matheron named it under the binomial Hypselosaurus priscus. The holotype specimen includes a partial hindlimb and a pair of caudal vertebrae, and two eggshell fragments were found alongside these bones. Because of the proximity of these eggshells to the fossil remains, many later authors, including Matheron and Paul Gervais, have assigned several eggs from the same region of France all to Hypselosaurus, although the variation and differences between these eggs suggest that they do not all belong to the same taxon. Hypselosaurus has been found in the same formation as the dromaeosaurids Variraptor and Pyroraptor, the ornithopod Rhabdodon, and the ankylosaurian Rhodanosaurus, as well as indeterminate bones from other groups.
Dinosaur eggs are the organic vessels in which a dinosaur embryo develops. When the first scientifically documented remains of non-avian dinosaurs were being described in England during the 1820s, it was presumed that dinosaurs had laid eggs because they were reptiles. In 1859, the first scientifically documented dinosaur egg fossils were discovered in France by Jean-Jacques Poech, although they were mistaken for giant bird eggs.
Elongatoolithus is an oogenus of dinosaur eggs found in the Late Cretaceous formations of China and Mongolia. Like other elongatoolithids, they were laid by small theropods, and were cared for and incubated by their parents until hatching. They are often found in nests arranged in multiple layers of concentric rings. As its name suggests, Elongatoolithus was a highly elongated form of egg. It is historically significant for being among the first fossil eggs given a parataxonomic name.
Dictyoolithus is an oogenus of dinosaur egg from the Cretaceous of China. It is notable for having over five superimposed layers of eggshell units. Possibly, it was laid by megalosauroid dinosaurs.
Cairanoolithus is an oogenus of dinosaur egg which is found in Southwestern Europe. The eggs are large and spherical. Their outer surface is either smooth, or covered with a subdued pattern of ridges interspersed with pits and grooves. Multiple fossil egg clutches are known but the nest structure is unclear.
Sphaerovum is an oogenus of dinosaur egg that has only been discovered in South America.
Spheroolithus is an oogenus of dinosaur egg.
Macroolithus is an oogenus of dinosaur egg belonging to the oofamily Elongatoolithidae. The type oospecies, M. rugustus, was originally described under the now-defunct oogenus name Oolithes. Three other oospecies are known: M. yaotunensis, M. mutabilis, and M. lashuyuanensis. They are relatively large, elongated eggs with a two-layered eggshell. Their nests consist of large, concentric rings of paired eggs. There is evidence of blue-green pigmentation in its shell, which may have helped camouflage the nests.
Phaceloolithus is an oogenus of dinosaur egg found in the Fenshui'ao Formation of the Dongting Basin of the Hunan Province of China. The eggs have a subspherical shape, measuring up to 168 mm on the long axis, and having a very thin shell.
Continuoolithus is an oogenus of dinosaur egg found in the late Cretaceous of North America. It is most commonly known from the late Campanian of Alberta and Montana, but specimens have also been found dating to the older Santonian and the younger Maastrichtian. It was laid by an unknown type of theropod. These small eggs are similar to the eggs of oviraptorid dinosaurs, but have a distinctive type of ornamentation.
Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of the once-developing embryo inside, in which case it also contains body fossils. A wide variety of different animal groups laid eggs that are now preserved in the fossil record beginning in the Paleozoic. Examples include invertebrates like ammonoids as well as vertebrates like fishes, possible amphibians, and reptiles. The latter group includes the many dinosaur eggs that have been recovered from Mesozoic strata. Since the organism responsible for laying any given egg fossil is frequently unknown, scientists classify eggs using a parallel system of taxonomy separate from but modeled after the Linnaean system. This "parataxonomy" is called veterovata.
Paraelongatoolithus is a late Cretaceous oogenus of Chinese fossil egg, classified in the oofamily Elongatoolithidae, which represents the eggs of oviraptorosaurs.
Egg paleopathology is the study of evidence for illness, injury, and deformity in fossilized eggs. A variety of pathological conditions afflicting eggs have been documented in the fossil record. Examples include eggshell of abnormal thickness and fossil eggs with multiple layers of eggshell. The identification of egg paleopathologies is complicated by the fact that even healthy eggs can be modified during or after fossilization. Paleontologists can use techniques like cathodoluminescence or thin sectioning to identify true paleopathologies in fossil eggs. Despite the diversity of paleopathologies known from fossil eggs, the vast majority of conditions known to afflict modern eggs have not yet been seen among fossils.
Coralloidoolithus is an oogenus of dinosaur egg from the Tiantai Basin in Zhejiang Province, containing a single known oospecies C. shizuiwanensis. Formerly, it was classified in the oogenus Paraspheroolithus; however, it was considered sufficiently different to be classified in its own genus. C. shizuiwanensis is similar to Stalicoolithus, leading to their classification in the same family, Stalicoolithidae.
Elongatoolithidae is an oofamily of fossil eggs, representing the eggs of oviraptorosaurs. They are known for their highly elongated shape. Elongatoolithids have been found in Europe, Asia, and both North and South America.
Guegoolithus is an oogenus of fossil egg from the early Cretaceous of Spain. It is classified in the oofamily Spheroolithidae, and was probably laid by an ornithopod dinosaur.
Polyclonoolithus is an oogenus of fossil dinosaur egg. It is from the Early Cretaceous of Gansu, China. They have distinctive, branching eggshell units, which may represent the original form of spheroolithids.
Dictyoolithidae is an oofamily of dinosaur eggs which have a distinctive reticulate organization of their eggshell units. They are so far known only from Cretaceous formations in China.
Gobioolithus is an oogenus of fossil bird egg native to Mongolia. They are small, smooth-shelled, and elongated eggs that were first discovered in the 1960s and early 70s during a series of fossil-hunting expeditions in the Gobi Desert. Two oospecies have been described: Gobioolithus minor and G. major. The eggs were probably laid in colonial nesting sites on the banks of rivers and lakes.
Nanhsiungoolithus is an oogenus of dinosaur egg from the late Cretaceous of China. It belongs to the oofamily Elongatoolithidae, which means that it was probably laid by an oviraptorosaur, though so far no skeletal remains have been discovered in association with Nanhsiungoolithus. The oogenus contains only a single described oospecies, N. chuetienensis. It is fairly rare, only being know from two partially preserved nests and a few eggshell fragments.
