| Protoceratopsidovum Temporal range: Campanian ~ | |
|---|---|
Egg fossil classification  | |
| Basic shell type: | † Dinosauroid-prismatic |
| Oofamily: | † Prismatoolithidae |
| Oogenus: | † Protoceratopsidovum Mikhailov, 1994 |
| Oospecies | |
| |
Protoceratopsidovum is an oogenus of dinosaur egg from Mongolia. Despite its name (which means "eggs of Protoceratops " [1] ), it does not represent the eggs of a protoceratopsid, but rather the eggs of maniraptoran theropods. [2] [3]
Protoceratopsidovum eggs are extremely abundant in the Djadokhta and Barun Goyot Formations. [4] P. sincerum and P. minimum eggs both have a smooth surface, whereas those of P. fluxuosum have fine ornamentation around the equatorial part. [4] The eggs are elongated and asymmetrical, with a two-layered prismatic shell generally resembling the eggs of Troodon . [5] They were laid in pairs. [3]
The eggs of Protoceratopsidovum are classified in the oofamily Prismatoolithidae. [4] They were originally thought to be eggs of Protoceratops (hence the name) because they are extremely common at the same sites as Protoceratops. [4] However, more recent research has cast doubt on this: a cladistic analysis in 2008, by Zelenitsky and Therrien, found them to be the eggs of maniraptorans. [3]
The shape, structure, and arrangement of eggs of Protoceratopsidovum and its relatives provide some insight into the palaeobiology of fossil eggs. Their asymmetrical shape (resembling bird eggs) suggests that the process of egg formation was similar to that of birds. Unlike bird eggs (which are laid one at a time), Protoceratopsidovum eggs were laid in pairs because the mother would have two functioning oviducts which would both lay a single egg simultaneously, contrasting with modern birds, which have only one functional oviduct. Though no fossils of parents incubating Protoceratopsidovum eggs have been found, their identification as maniraptoran eggs would imply that they were incubated. [3]
Oviraptoridae is a group of bird-like, herbivorous and omnivorous maniraptoran dinosaurs. Oviraptorids are characterized by their toothless, parrot-like beaks and, in some cases, elaborate crests. They were generally small, measuring between one and two metres long in most cases, though some possible oviraptorids were enormous. Oviraptorids are currently known only from the Late Cretaceous of Asia, with the most well-known species and complete specimens found only in the Gobi Desert of Mongolia and northwestern China.
Protoceratops is a genus of small protoceratopsid dinosaurs that lived in Asia during the Late Cretaceous, around 75 to 71 million years ago. The genus Protoceratops includes two species: P. andrewsi and the larger P. hellenikorhinus. The former was described in 1923 with fossils from the Mongolian Djadokhta Formation, and the latter in 2001 with fossils from the Chinese Bayan Mandahu Formation. Protoceratops was initially believed to be an ancestor of ankylosaurians and larger ceratopsians, such as Triceratops and relatives, until the discoveries of other protoceratopsids. Populations of P. andrewsi may have evolved into Bagaceratops through anagenesis.
Oviraptorosaurs are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, with or without bony crests atop the head. They ranged in size from Caudipteryx, which was the size of a turkey, to the 8-meter-long, 1.4-ton Gigantoraptor. The group is close to the ancestry of birds. Analyses like those of Maryanska et al (2002) and Osmólska et al. (2004) suggest that they may represent primitive flightless birds. The most complete oviraptorosaur specimens have been found in Asia. The North American oviraptorosaur record is sparse.
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.
Macroelongatoolithus is an oogenus of large, fossil theropod eggs. They are known from Asia and from North America.
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.
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.
Dispersituberoolithus is an oogenus of fossil egg, which may have been laid by a bird or non-avian theropod.
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.
Montanoolithus is an oogenus of fossil egg found in Montana and Alberta. They were probably laid by a dromaeosaur or a caenagnathid.
This timeline of oviraptorosaur research is a chronological listing of events in the history of paleontology focused on the oviraptorosaurs, a group of beaked, bird-like theropod dinosaurs. The early history of oviraptorosaur paleontology is characterized by taxonomic confusion due to the unusual characteristics of these dinosaurs. When initially described in 1924 Oviraptor itself was thought to be a member of the Ornithomimidae, popularly known as the "ostrich" dinosaurs, because both taxa share toothless beaks. Early caenagnathid oviraptorosaur discoveries like Caenagnathus itself were also incorrectly classified at the time, having been misidentified as birds.
Wendy Sloboda is a Canadian fossil hunter from Warner, Alberta. She has made fossil discoveries of dinosaurs and other extinct animals on several continents, with finds in Canada, Argentina, Mongolia, France, and Greenland. She is commemorated in name of the horned dinosaur Wendiceratops, remains of which she discovered in 2010, as well as the fossil footprint Barrosopus slobodai which she discovered in 2003.
Parvoolithus is an oogenus of Mongolian fossil eggs from the Campanian Barun Goyot Formation. They are known from a single small, smooth egg, which cannot be assigned to any known oofamily. It is very similar to the eggs of modern birds in many aspects; in fact, a cladistic analysis by Zelenitsky and Therrien found it to be a sister taxon to the guinea fowl, indicating that they represent the eggs of birds, rather than a non-avialan theropod.
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.
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.
Trigonoolithus is an oogenus of dinosaur egg, representing a basal prismatoolithid. Its eggshell, like avian eggs, is composed of three structural layers, but cladistic analysis suggests that its parent was a non-avian theropod.
Incognitoolithus is an oogenus of medioolithid fossil bird egg. It is notable for bearing evidence of predation, possibly from a bird pecking the eggshell.
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.