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Triprismatoolithus
''Triprismatoolithus'' is an oogenus of dinosaur egg native to Teton County, Montana. It is classified in the oofamily Arriagadoolithidae, the eggs of alvarezsaurs. Distribution ''Triprismatoolithus'' is known exclusively from Sevenmile Hill, a fossil site at the Two Medicine Formation in Teton County, Montana. It is the oldest known fossil egg site at that formation, dating to 80 million years ago, the early part of the Campanian. History Fossil eggs are common from the upper part of the Two Medicine formation, but it was not until 2010 that paleontologists discovered eggs in the lower part, including ''Triprismatoolithus''. They were discovered by two paleontologists from the University of Montana: Frankie D. Jackson and David J. Varricchio. It remained of uncertain classification (because no similar eggs were known) until 2012 when Agnolin '' et al.'' discovered similar eggs associated with ''Bonapartenykus'', which they classified with ''Triprismatoolithus'' in a new oofamily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arriagadoolithidae
Arriagadoolithidae is an oofamily of fossil eggs, representing the eggs of Alvarezsaurs. Description The eggs are well stratified with three layers: the external, the prismatic, and the mammillary. The connection between prismatic and external layers is abrupt. The eggshell is similar to that of birds, and has ornamentation similar to that of Elongatoolithids. History Previously, Arriagadoolithid eggs were considered to be Elongatoolithids, because the similarities in shell ornamentation. However, they have quite distinct eggshell structure, which was recognized by Jackson and Varricchio (2010) when they named a new oogenus, '' Triprismatoolithus''. The oofamily was first described in 2012, following the discovery of fossil eggs associated with the Alvarezsaur, ''Bonapartenykus''; Agnolin ''et al'' erected a new oogenus, ''Arriagadoolithus ''Arriagadoolithus'' is the oogenus of fossil eggs which includes the eggs of the alvarezsaurid ''Bonapartenykus''. Fossils of the creature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continuoolithus
''Continuoolithus'' is an oogenus (fossil egg genus) 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 (measuring long) are similar to the eggs of oviraptorid dinosaurs (oofamily Elongatoolithidae), but have a distinctive type of ornamentation. ''Continuoolithus'' nests would have been incubated under vegetation and sediment, unlike nests of '' Troodon'' and oviraptorids, which were incubated by brooding adults. Adaptations in the eggshell, such as high porosity and prominent ornamentation, would have helped the embryo breathe while buried. One fossil egg contains a tiny embryonic skeleton at an exceptionally young stage of development (perhaps eight to ten days old) showing the earliest stages of bone development. Description Complet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milk River Formation
The Milk River Formation is a sandstone-dominated stratigraphic unit of the Western Canada Sedimentary Basin in southern Alberta, Canada. It was deposited in near-shore to coastal environments during Late Cretaceous (late Santonian to early Campanian) time. Based on uranium-lead dating, palynology and stratigraphic relationships, deposition occurred between ~84.1 and 83.6 Ma. The sandstones of the Virgelle Member in the centre of the formation are well-exposed at Writing-on-Stone Provincial Park in southwestern Alberta, where they bear petroglyphs carved into them by First Nations people. The formation is fossiliferous and has yielded an extensive vertebrate fauna (see Tables below), as well as fossil ammonites. In some areas it hosts shallow natural gas reservoirs.Payenberg, T.D.H., Braman, D.R. and Miall, A.D. 2003. Depositional environments and stratigraphic architecture of the Late Cretaceous and Eagle formations, southern Alberta and north-central Montana: Relationships to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oogenus
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''. History The first named oospecies was '' Oolithes bathonicae'', a name given provisi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arriagadoolithus
''Arriagadoolithus'' is the oogenus of fossil eggs which includes the eggs of the alvarezsaurid ''Bonapartenykus''. Fossils of the creature were found in Patagonia; it may have brooded on its eggs. Description ''Arriagadoolithus patagoniensis'' is known from two partial eggs both found associated with a skeleton of ''Bonapartenykus ultimus''. The eggs are about in maximum width, but the length of the eggs and whether or not they were symmetric are unknown. Unlike most non-avian dinosaur eggs,Laura E. Wilson, Karen Chin, Frankie D. Jackson, and Emily S. BrayII. Eggshell morphology and structure ''UCMP Online Exhibits: Fossil Eggshell'' ''Arriagadoolithus'' shell has three layers (external, prismatic, and mammillary). The shell is approximately thick. The outer surface of its eggshell is covered with two distinct ornamentation patterns: the unique dendro-reticulate ornament, made up of randomly interconnecting ridges with nodes along the ridges or where they intersect; and the pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oviraptorosaurs
Oviraptorosaurs ("egg thief lizards") 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 (along with all maniraptoran dinosaurs) is close to the ancestry of birds. Some researchers such as Maryanska ''et al'' (2002) and Osmólska ''et al.'' (2004) have proposed that they may represent primitive flightless birds.Osmólska, Halszka, Currie, Philip J., Brasbold, Rinchen (2004) "The Dinosauria" Weishampel, Dodson, Osmólska. "Chapter 8 Oviraptorosauria" University of California Press. The most complete oviraptorosaur specimens have been found in Asia. The North American oviraptorosaur record is sparse.Varricchio, D. J. 2001. Late Cretaceous oviraptorosaur (Theropoda) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alvarezsaurid
Alvarezsauridae is a family of small, long-legged dinosaurs. Although originally thought to represent the earliest known flightless birds, they are now thought to be an early diverging branch of maniraptoran theropods. Alvarezsaurids were highly specialized. They had tiny but stout forelimbs, with compact, bird-like hands. Their skeletons suggest that they had massive breast and arm muscles, possibly adapted for digging or tearing. They had long, tube-shaped snouts filled with tiny teeth. They have been interpreted as myrmecophagous, adapted to prey on colonial insects such as termites, with the short arms acting as effective digging instruments to break into nests. ''Alvarezsaurus'', the type genus of the family, was named for the historian Gregorio Álvarez. History of study Bonaparte (1991) described the first alvarezsaurid, ''Alvarezsaurus calvoi'', from an incomplete skeleton found in Patagonia, Argentina. Bonaparte also named a family, Alvarezsauridae, to contain it. He a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elongatoolithidae
Elongatoolithidae is an oofamily of fossil eggs, representing the eggs of oviraptorosaurs (with the exception of the avian '' Ornitholithus''). They are known for their highly elongated shape. Elongatoolithids have been found in Europe, Asia, and both North and South America.Simon, D. J. (2014).Giant Dinosaur (theropod) Eggs of the Oogenus Macroelongatoolithus (Elongatoolithidae) from Southeastern Idaho: Taxonomic, Paleobiogeographic, and Reproductive Implications. (Doctoral dissertation, Montana State University, Bozeman). Distribution Elongatoolithids have a very broad distribution. They have been found across Asia and the US, as well as in Spain, France, and Argentina, with ages ranging from lower Cretaceous to the Paleocene. Description Elongatoolithids are, as their name suggests, highly elongated eggs; they are at least twice as long as they are wide. They vary widely in size, ranging from the 7 cm long ''Elongatoolithus chichengshanensis'' to the gigantic 60 cm ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prismatoolithidae
Prismatoolithidae is an oofamily of fossil eggs. They may have been laid by ornithopods or theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...s. References Egg fossils Dinosaur reproduction {{eggshell-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Parataxa Described In 2010
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troodontids
Troodontidae is a clade of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil discoveries of complete and articulated specimens (including specimens which preserve feathers, eggs, embryos, and complete juveniles), have helped to increase understanding about this group. Anatomical studies, particularly studies of the most primitive troodontids, like ''Sinovenator'', demonstrate striking anatomical similarities with ''Archaeopteryx'' and primitive dromaeosaurids, and demonstrate that they are relatives comprising a clade called Paraves. Description Troodontids are a group of small, bird-like, gracile maniraptorans. All troodontids have unique features of the skull, such as large numbers of closely spaced teeth in the lower jaw. Troodontids have sickle-claws and raptorial hands, and some of the highest non-avian encephaliza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oviducts
The oviduct in mammals, is the passageway from an ovary. In human females this is more usually known as the Fallopian tube or uterine tube. The eggs travel along the oviduct. These eggs will either be fertilized by spermatozoa to become a zygote, or will degenerate in the body. Normally, these are paired structures, but in birds and some cartilaginous fishes, one or the other side fails to develop (together with the corresponding ovary), and only one functional oviduct can be found. Except in teleosts, the oviduct is not directly in contact with the ovary. Instead, the most anterior portion ends in a funnel-shaped structure called the infundibulum, which collects eggs as they are released by the ovary into the body cavity. The only female vertebrates to lack oviducts are the jawless fishes. In these species, the single fused ovary releases eggs directly into the body cavity. The fish eventually extrudes the eggs through a small genital pore towards the rear of the body. Fish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
