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Sankofa (oogenus)
''Sankofa'' is an oogenus of prismatoolithid egg. They are fairly small, smooth-shelled, and asymmetrical. ''Sankofa'' may represent the fossilized eggs of a transitional species between non-avian theropods and birds. Etymology The name ''Sankofa'' comes from the Ashante word "sankofa", meaning 'learning from the past', symbolized by a bird with an egg in its bill. The oospecific epiphet ''pyrenaica'' refers to the Pyrenees, where the eggs were first discovered. Distribution ''Sankofa pyrenaica'' is known solely from the Aren Formation, in the southern Pyrenees of Catalonia, Spain, dating from the Upper Campanian to Lower Maastrichtian. Description ''Sankofa'' eggs are uniformly 7 cm long and 4 cm wide, and their eggshell averages 0.27 mm thick. The eggshell consists of two layers, the prismatic (or palisade) layer and the mammillary layer, similar to most other non-avian dinosaur eggshells.Laura E. Wilson, Karen Chin, Frankie D. Jackson, and Emily S. Bray. ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia and Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UCMP
The University of California Museum of Paleontology (UCMP) is a paleontology museum located on the campus of the University of California, Berkeley. The museum is within the Valley Life Sciences Building (VLSB), designed by George W. Kelham and completed in 1930. Its collections are primarily intended for research and are, thus, not accessible to the public. A limited number of fossils from the collection is on display in the VLSB. Although located on the Berkeley campus, the museum is the primary locality for storing fossils collected statewide. The original fossils, around which the current collection has grown, were those gathered as part of the California Geological Survey from 1860-1867. Website UCMP was one of the first museums to have its own website in the early 1990s, due to its location within a technology-oriented university with a good Internet connection. The site has been applauded for its use of visually appealing graphics, was nominated for a Webby Award five ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egg Fossils
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] |
Fossils Of Spain
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, Seashell, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in #Resin, 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 stratum, 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 quantitativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Origin Of Birds
The scientific question of within which larger group of animals evolution of birds, birds evolved has traditionally been called the "origin of birds". The present scientific consensus is that birds are a group of maniraptoran Theropoda, theropod dinosaurs that evolution, originated during the Mesozoic, Mesozoic Era. A close relationship between birds and dinosaurs was first proposed in the nineteenth century after the discovery of the primitive bird ''Archaeopteryx'' in Germany. Birds and extinct non-avian dinosaurs share many unique skeletal traits. Moreover, fossils of more than thirty species of non-avian dinosaur with preserved feathers have been collected. There are even very small dinosaurs, such as ''Microraptor'' and ''Anchiornis'', which have long, Feathers#Structures and characteristics, vaned arm and leg feathers forming wings. The Jurassic basal avialan ''Pedopenna'' also shows these long foot feathers. Paleontology, Paleontologist Lawrence Witmer concluded in 2009 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoceratopsidovum
''Protoceratopsidovum'' is an oogenus of dinosaur egg from Mongolia. Despite its name (which means "eggs of ''Protoceratops''"Zelenitsky, D., and Currie, P. (2004) "A Cladistic Analysis of Theropod Ootaxa." ''Journal of Vertebrate Paleontology.'' Vol. 24, Supplement 003: Abstracts of Papers Sixty-Fourth Annual Meeting Society of Vertebrate Paleontology Adams Mark Hotel Denver, Colorado November 3–6.), it does not represent the eggs of a protoceratopsid, but rather the eggs of maniraptoran theropods.Carpenter, K. 1999. Eggs, Nests, and Baby Dinosaurs: A Look at Dinosaur Reproduction (Life of the Past). Indiana University Press, Bloomington, Indiana.Zelenitsky, D. K. And Therrien, F. (2008),Phylogenetic Analysis Of Reproductive Traits Of Maniraptoran Theropods And Its Implications For Egg Parataxonomy" ''Palaeontology'', 51: 807–816. Description ''Protoceratopsidovum'' eggs are extremely abundant in the Djadokhta and Barun Goyot Formations.Mikhailov, K.E. (2000). "Eggs and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polytomy
An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. A tree that contains any multifurcations can be described as a multifurcating tree. Soft polytomies vs. hard polytomies Two types of polytomies are recognised, soft and hard polytomies. Soft polytomies are the result of insufficient phylogenetic information: though the lineages diverged at different times – meaning that some of these lineages are closer relatives than others, and the available data does not allow recognition of this. Most polytomies are soft, meaning that they would be resolved into a typical tree of dichotomies if better data were available. In contrast, a hard polytomy represents a true divergence event of three or more lineages. Applications Interpretations for a polytomy depend on the individuals, that are represe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladistic Analysis
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived characteristics (synapomorphies'')'' that are not present in more distant groups and ancestors. However, from an empirical perspective, common ancestors are inferences based on a cladistic hypothesis of relationships of taxa whose character states can be observed. Theoretically, a last common ancestor and all its descendants constitute a (minimal) clade. Importantly, all descendants stay in their overarching ancestral clade. For example, if the terms ''worms'' or ''fishes'' were used within a ''strict'' cladistic framework, these terms would include humans. Many of these terms are normally used paraphyletically, outside of cladistics, e.g. as a 'grade', which are fruitless to precisely delineate, especially when including extinct species. Radi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, the fourth-largest country in the Americas, and the eighth-largest country in the world. It shares the bulk of the Southern Cone with Chile to the west, and is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. Argentina is a federal state subdivided into twenty-three provinces, and one autonomous city, which is the federal capital and largest city of the nation, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a federal system. Argentina claims sovereignty over the Falkland Islands, South Georgia and the South Sandwich Islands, and a part of Antarctica. The earliest recorded human prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bajo De La Carpa Formation
The Bajo de la Carpa Formation is a geologic formation of the Neuquén Basin that crops out in northern Patagonia, in the provinces of Río Negro and Neuquén, Argentina. It is the oldest of two formations belonging to the Río Colorado Subgroup within the Neuquén Group. Formerly, that subgroup was treated as a formation, and the Bajo de la Carpa Formation was known as the Bajo de la Carpa Member.Sánchez ''et al.'', 2006 At its base, this formation conformably overlies the Plottier Formation of the older Río Neuquén Subgroup, and it is in turn overlain by the Anacleto Formation, the youngest and uppermost formation of the Neuquén Group. The Bajo de la Carpa Formation can reach in thickness in some locations, and consists mainly of sandstones of various colors, all of fluvial origin, with thin layers of mudstone and siltstone in between. Geological features such as geodes, chemical nodules, impressions of raindrops, and paleosols (fossil soils) are commonly found in this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enantiornithine
The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over eighty species of Enantiornithes have been named, but some names represent only single bones, so it is likely that not all are valid. The Enantiornithes became extinct at the Cretaceous–Paleogene boundary, along with Hesperornithes and all other non-avian dinosaurs. Discovery and naming The first Enantiornithes to be discovered were incorrectly referred to modern bird groups. For example, the first known species of Enantiornithes, ''Gobipteryx minuta'', was originally considered a paleognath related to ostriches and tinamou. The Enantiornithes were first recognized as a distinct lineage, or "subclass" of birds, by Cyril A. Walker in 1981. Walker mad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nieves López Martínez
Nieves López Martínez (Burgos, 5 February 1949 - Madrid, 15 December 2010) was a Spanish paleontologist specializing in research on the vertebrate fossil record and part of a group of paleontologists who were responsible for the modernization of paleontological studies in Spain. López Martínez studied at Complutense University of Madrid, graduating in Biological Sciences in 1970. She received a scholarship to do her PhD work, under the supervision of Dr. Louis Thaler at the University of Montpellier. López Martínez was recognized as a leading figure in the study of the evolution of Cenozoic lagomorphs, as well as the Cretaceous–Paleogene extinction event in the area of the Pyrenees. She was also very involved with university teaching programs, both officially at the Complutense University of Madrid and through various projects, such as the Somosaguas Paleontology Project, which was associated with the Somosaguas paleontological site.Fesharaki, O., Torices, A., Fernánd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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