Patagopteryx is an extinct monotypic genus of patagopterygiforms that lived during the Late Cretaceous, around 80 mya, in what is now the Sierra Barrosa in northwestern Patagonia, Argentina. About the size of a chicken, it is the earliest known unequivocal example of secondary flightlessness: its skeleton shows clear indications that the ancestors of Patagopteryx were flying birds. Located in strata of the Santonian Bajo de la Carpa Formation, the original remains were discovered by Oscar de Ferrariis, Director of the Natural History Museum of the Comahue National University in Neuquén around 1984-5, he passed them onto noted paleontologist José Bonaparte, who described the species Patagopteryx deferrariisi in 1992. The Patagopteryx had feet with fused bones, much like modern birds; the bird did not have a wishbone, meaning that it would have been impossible for it to have had the muscles necessary for flying. The legs had short femurs, characteristic of a running animal; the second toe has a curved claw.
It was omnivorous, traveled in flocks across the plains of South America. Origin of birds
France the French Republic, is a country whose territory consists of metropolitan France in Western Europe and several overseas regions and territories. The metropolitan area of France extends from the Mediterranean Sea to the English Channel and the North Sea, from the Rhine to the Atlantic Ocean, it is bordered by Belgium and Germany to the northeast and Italy to the east, Andorra and Spain to the south. The overseas territories include French Guiana in South America and several islands in the Atlantic and Indian oceans; the country's 18 integral regions span a combined area of 643,801 square kilometres and a total population of 67.3 million. France, a sovereign state, is a unitary semi-presidential republic with its capital in Paris, the country's largest city and main cultural and commercial centre. Other major urban areas include Lyon, Toulouse, Bordeaux and Nice. During the Iron Age, what is now metropolitan France was inhabited by a Celtic people. Rome annexed the area in 51 BC, holding it until the arrival of Germanic Franks in 476, who formed the Kingdom of Francia.
The Treaty of Verdun of 843 partitioned Francia into Middle Francia and West Francia. West Francia which became the Kingdom of France in 987 emerged as a major European power in the Late Middle Ages following its victory in the Hundred Years' War. During the Renaissance, French culture flourished and a global colonial empire was established, which by the 20th century would become the second largest in the world; the 16th century was dominated by religious civil wars between Protestants. France became Europe's dominant cultural and military power in the 17th century under Louis XIV. In the late 18th century, the French Revolution overthrew the absolute monarchy, established one of modern history's earliest republics, saw the drafting of the Declaration of the Rights of Man and of the Citizen, which expresses the nation's ideals to this day. In the 19th century, Napoleon established the First French Empire, his subsequent Napoleonic Wars shaped the course of continental Europe. Following the collapse of the Empire, France endured a tumultuous succession of governments culminating with the establishment of the French Third Republic in 1870.
France was a major participant in World War I, from which it emerged victorious, was one of the Allies in World War II, but came under occupation by the Axis powers in 1940. Following liberation in 1944, a Fourth Republic was established and dissolved in the course of the Algerian War; the Fifth Republic, led by Charles de Gaulle, remains today. Algeria and nearly all the other colonies became independent in the 1960s and retained close economic and military connections with France. France has long been a global centre of art and philosophy, it hosts the world's fourth-largest number of UNESCO World Heritage Sites and is the leading tourist destination, receiving around 83 million foreign visitors annually. France is a developed country with the world's sixth-largest economy by nominal GDP, tenth-largest by purchasing power parity. In terms of aggregate household wealth, it ranks fourth in the world. France performs well in international rankings of education, health care, life expectancy, human development.
France is considered a great power in global affairs, being one of the five permanent members of the United Nations Security Council with the power to veto and an official nuclear-weapon state. It is a leading member state of the European Union and the Eurozone, a member of the Group of 7, North Atlantic Treaty Organization, Organisation for Economic Co-operation and Development, the World Trade Organization, La Francophonie. Applied to the whole Frankish Empire, the name "France" comes from the Latin "Francia", or "country of the Franks". Modern France is still named today "Francia" in Italian and Spanish, "Frankreich" in German and "Frankrijk" in Dutch, all of which have more or less the same historical meaning. There are various theories as to the origin of the name Frank. Following the precedents of Edward Gibbon and Jacob Grimm, the name of the Franks has been linked with the word frank in English, it has been suggested that the meaning of "free" was adopted because, after the conquest of Gaul, only Franks were free of taxation.
Another theory is that it is derived from the Proto-Germanic word frankon, which translates as javelin or lance as the throwing axe of the Franks was known as a francisca. However, it has been determined that these weapons were named because of their use by the Franks, not the other way around; the oldest traces of human life in what is now France date from 1.8 million years ago. Over the ensuing millennia, Humans were confronted by a harsh and variable climate, marked by several glacial eras. Early hominids led a nomadic hunter-gatherer life. France has a large number of decorated caves from the upper Palaeolithic era, including one of the most famous and best preserved, Lascaux. At the end of the last glacial period, the climate became milder. After strong demographic and agricultural development between the 4th and 3rd millennia, metallurgy appeared at the end of the 3rd millennium working gold and bronze, iron. France has numerous megalithic sites from the Neolithic period, including the exceptiona
Chondrichthyes is a class that contains the cartilaginous fishes: they are jawed vertebrates with paired fins, paired nares, scales, a heart with its chambers in series, skeletons made of cartilage rather than bone. The class is divided into two subclasses: Holocephali. Within the infraphylum Gnathostomata, cartilaginous fishes are distinct from all other jawed vertebrates; the skeleton is cartilaginous. The notochord is replaced by a vertebral column during development, except in Holocephali, where the notochord stays intact. In some deepwater sharks, the column is reduced; as they do not have bone marrow, red blood cells are produced in the epigonal organ. They are produced in the Leydig's organ, only found in certain cartilaginous fishes; the subclass Holocephali, a specialized group, lacks both the Leydig's and epigonal organs. Apart from electric rays, which have a thick and flabby body, with soft, loose skin, chondrichthyans have tough skin covered with dermal teeth called placoid scales, making it feel like sandpaper.
In most species, all dermal denticles are oriented in one direction, making the skin feel smooth if rubbed in one direction and rough if rubbed in the other. The pectoral and pelvic girdles, which do not contain any dermal elements, did not connect. In forms, each pair of fins became ventrally connected in the middle when scapulocoracoid and pubioischiadic bars evolved. In rays, the pectoral fins have connected to the head and are flexible. One of the primary characteristics present in most sharks is the heterocercal tail, which aids in locomotion. Chondrichthyans have toothlike scales called placoid scales. Denticles provide protection, in most cases, streamlining. Mucous glands exist in some species, as well, it is assumed that their oral teeth evolved from dermal denticles that migrated into the mouth, but it could be the other way around, as the teleost bony fish Denticeps clupeoides has most of its head covered by dermal teeth. This is most a secondary evolved characteristic, which means there is not a connection between the teeth and the original dermal scales.
The old placoderms had sharp bony plates in their mouth. Thus, it is unknown whether the oral teeth evolved first, it has been suggested that the original bony plates of all vertebrates are now gone and that the present scales are just modified teeth if both the teeth and body armor had a common origin a long time ago. However, there is no evidence of this. All chondrichthyans breathe through five depending on the species. In general, pelagic species must keep swimming to keep oxygenated water moving through their gills, whilst demersal species can pump water in through their spiracles and out through their gills. However, this is only a general rule and many species differ. A spiracle is a small hole found behind each eye; these can be tiny and circular, such as found on the nurse shark, to extended and slit-like, such as found on the wobbegongs. Many larger, pelagic species, such as the mackerel sharks and the thresher sharks, no longer possess them. Chondrichthyes nervous system is composed of a small brain, 8-10 pairs of cranial nerves, a spinal chord with spinal nerves.
They have several sensory organs. Ampullae of Lorenzini are a network of small jelly filled pores called electroreceptors which help the fish sense electric fields in water; this aids in finding prey and sensing temperature. The Lateral line system has modified epithelial cells located externally which sense motion and pressure in the water around them. Most subspecies have large well-developed eyes, they have powerful nostrils and olfactory organs. Their inner ears consist of 3 large semicircular canals which aid in orientation, their sound detecting apparatus has limited range and is more powerful at lower frequencies. Some subspecies have electric organs which can be used for predation, they have simple brains with the forebrain not enlarged. The structure and formation of myelin in their nervous systems are nearly identical to that of tetrapods, which has led evolutionary biologists to believe that Chondrichthyes were a cornerstone group in the evolutionary timeline of myelin development. Like all other jawed vertebrates, members of Chondrichthyes have an adaptive immune system.
Fertilization is internal. Development is live birth but can be through eggs; some rare species are viviparous. There is no parental care after birth. Capture-induced premature birth and abortion occurs in sharks/rays when fished. Capture-induced parturition is mistaken for natural birth by recreational fishers and is considered in commercial fisheries management despite being shown to occur in at least 12% of live bearing sharks and rays; the class Chondrichthyes has two subclasses: the subclass Elasmobranchii
In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 132.9 ± 2.0 Ma. The Valanginian stage succeeds the Berriasian stage of the Lower Cretaceous and precedes the Hauterivian stage of the Lower Cretaceous; the Valanginian was first described and named by Édouard Desor in 1853. It is named after a small town north of Neuchâtel in the Jura Mountains of Switzerland; the base of the Valanginian is at the first appearance of calpionellid species Calpionellites darderi in the stratigraphic column. A global reference section had in 2009 not yet been appointed; the top of the Valanginian is at the first appearance of the ammonite genus Acanthodiscus. The Valanginian is subdivided in Lower and Upper substages; the Upper substage begins at the first appearance of ammonite species Saynoceras verrucosum and the major marine transgression Va3. In the Tethys domain, the Valanginian stage contains five ammonite biozones: zone of Criosarasinella furcillata zone of Neocomites peregrinus zone of Saynoceras verrucosum zone of Busnardoites campylotoxus zone of Tirnovella pertransiens Gradstein, F.
M.. G. & Smith, A. G.. GeoWhen Database - Valanginian Mid-Cretaceous timescale and ühttp://stratigraphy.science.purdue.edu/charts/Timeslices/5_JurCret.pdf Jurassic-Cretaceous timescale], at the website of the subcommission for stratigraphic information of the ICS Stratigraphic chart of the Lower Cretaceous, at the website of Norges Network of offshore records of geology and stratigraphy
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them. The aim is correlation, demonstrating that a particular horizon in one geological section represents the same period of time as another horizon at some other section; the fossils are useful because sediments of the same age can look different because of local variations in the sedimentary environment. For example, one section might have been made up of clays and marls while another has more chalky limestones, but if the fossil species recorded are similar, the two sediments are to have been laid down at the same time. Biostratigraphy originated in the early 19th century, where geologists recognised that the correlation of fossil assemblages between rocks of similar type but different age decreased as the difference in age increased; the method was well-established. Ammonites, graptolites and trilobites are index fossils that are used in biostratigraphy.
Microfossils such as acritarchs, conodonts, dinoflagellate cysts, pollen and foraminiferans are frequently used. Different fossils work well for sediments of different ages. To work well, the fossils used must be widespread geographically, so that they can occur in many different places, they must be short lived as a species, so that the period of time during which they could be incorporated in the sediment is narrow. The longer lived the species, the poorer the stratigraphic precision, so fossils that evolve such as ammonites, are favoured over forms that evolve much more like nautiloids. Biostratigraphic correlations are based on a fauna, not an individual species, as this allows greater precision. Further, if only one species is present in a sample, it can mean that the strata were formed in the known fossil range of that organism. For instance, the presence of the trace fossil Treptichnus pedum was used to define the base of the Cambrian period, but it has since been found in older strata.
Fossil assemblages were traditionally used to designate the duration of periods. Since a large change in fauna was required to make early stratigraphers create a new period, most of the periods we recognise today are terminated by a major extinction event or faunal turnover. A stage is a major subdivision of strata, each systematically following the other each bearing a unique assemblage of fossils. Therefore, stages can be defined as a group of strata containing the same major fossil assemblages. French palaeontologist Alcide d'Orbigny is credited for the invention of this concept, he named stages after geographic localities with good sections of rock strata that bear the characteristic fossils on which the stages are based. In 1856 German palaeontologist Albert Oppel introduced the concept of zone. A zone includes strata characterised by the overlapping range of fossils, they represent the time between the appearance of species chosen at the base of the zone and the appearance of other species chosen at the base of the next succeeding zone.
Oppel's zones are named after a particular distinctive fossil species, called an index fossil. Index fossils are one of the species from the assemblage of species; the zone is the fundamental biostratigraphic unit. Its thickness range from a few to hundreds of metres, its extant range from local to worldwide. Biostratigraphic units are divided into six principal kinds of biozones: Taxon range biozones represent the known stratigraphic and geographic range of occurrence of a single taxon. Concurrent range biozone include the concurrent, coincident, or overlapping part of the range of two specified taxa. Interval biozone include the strata between two specific biostratigraphic surfaces, it can be based on highest occurrences. Lineage biozone are strata containing species representing a specific segment of an evolutionary lineage. Assemblage biozones are strata. Abundance biozones are strata in which the abundance of a particular taxon or group of taxa is greater than in the adjacent part of the section.
To be useful in stratigraphic correlation index fossils should be: Independent of their environment Geographically widespread Rapidly evolvingEasy to preserve Easy to identify Fossil organisms succeed one another in a definite and determinable order and therefore any time period can be recognized by its fossil content. Biostratigraphic Lithostratigraphic Column Generator
The Maastrichtian is, in the ICS geologic timescale, the latest age of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, of the Mesozoic era or erathem. It spanned the interval from 72.1 to 66 million years ago. The Maastrichtian was succeeded by the Danian. At the end of this period, there was a mass extinction known as the Cretaceous–Paleogene extinction event. At this extinction event, many recognized groups such as non-avian dinosaurs and mosasaurs, as well as many other lesser-known groups, died out; the cause of the extinction is most linked to an asteroid about 10 to 15 kilometres wide colliding with Earth at the end of the Cretaceous. The Maastrichtian was introduced into scientific literature by Belgian geologist André Hubert Dumont in 1849, after studying rock strata of the Chalk Group close to the Dutch city of Maastricht; these strata are now classified as the Maastricht Formation - both formation and stage derive their names from the city. The Maastricht Formation is known for its fossils from this age, most notably those of the giant sea reptile Mosasaurus, which in turn derives its name from the Dutch city.
The base of the Maastrichtian stage is at the first appearance of ammonite species Pachydiscus neubergicus. At the original type locality near Maastricht, the stratigraphic record was found to be incomplete. A reference profile for the base was appointed in a section along the Ardour river called Grande Carrière, close to the village of Tercis-les-Bains in southwestern France; the top of the Maastrichtian stage is defined to be at the iridium anomaly at the Cretaceous–Paleogene boundary, characterised by the extinction of many groups of life, such as certain foraminifers and calcareous nanoplankton, all ammonites and belemnites, etc. The Maastrichtian is subdivided into two substages and three ammonite biozones; the biozones are: zone of Anapachydiscus terminus zone of Anapachydiscus fresvillensis zone of Pachydiscus neubergicus till Pachydiscus epiplectusThe Maastrichtian is coeval with the Lancian North American Land Mammal Age. The following are summaries of the characteristics of specific Maastrichtian aged formations.
The Bearpaw Formation called the Bearpaw Shale, is a sedimentary rock formation found in northwestern North America. It is exposed in the U. S. state of Montana, as well as the Canadian provinces of Alberta and Saskatchewan, east of the Rocky Mountains. It overlies the older Two Medicine, Judith River and Dinosaur Park Formations, is in turn overlain by the Horseshoe Canyon Formation in Canada and the Fox Hills Sandstone in Montana. To the east and south it blends into the Pierre Shale. A marine formation composed of shale, it represents the last major expansion of the Western Interior Seaway before it receded from northwestern North America by the end of the Cretaceous Period, it includes well-preserved ammonite fossils. Other fossils found in this formation include many types of shellfish, bony fish, rays and marine reptiles like mosasaurs and sea turtles; the occasional dinosaur remains have been discovered from carcasses washed out to sea. The Hell Creek Formation is an intensely studied division of Upper Cretaceous to lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana.
The Hell Creek Formation occurs in badlands of eastern Montana and portions of North Dakota, South Dakota, Wyoming. In Montana, the Hell Creek Formation overlies the Fox Hills Formation and is the uppermost formation of the Cretaceous period, it is a series of fresh and brackish-water clays and sandstones deposited during the Maastrichtian, the last part of the Cretaceous period, by fluvial activity in fluctuating river channels and deltas and occasional peaty swamp deposits along the low-lying eastern continental margin fronting the late Cretaceous Western Interior Seaway. The climate was mild; the iridium-enriched Cretaceous–Paleogene boundary, which separates the Cretaceous from the Cenozoic, occurs as a discontinuous but distinct thin marker bedding within the Formation, near its uppermost strata. The Horseshoe Canyon Formation is up to 230 m in depth, it is Late Campanian to Early Maastrichtian in age and is composed of mudstone and carbonaceous shales. There are a variety of environments.
The Horseshoe Canyon Formation outcrops extensively in the area of Drumheller, Alberta, as well as further north along the Red Deer River near Trochu, in the city of Edmonton. The Sarir field was discovered in southern Cyrenaica during 1961 and is considered to be the largest oil field in Libya, with estimated oil reserves of 12 Gbbl. Sarir is operated by the Arabian Gulf Oil Company, a subsidiary of the state-owned National Oil Corporation; the Sarir stratigraphic column resembles succession patterns throughout the Sirte Basin, with some variations. In the early regressive phase, basal sandstones were deposited on a Precambrian basement of igneous and metamorphic rocks. Sandstones are dated on angiosperm pollen as younger than Albian from the Late Cretaceous. After a lengthy hiatus, represented by unconformity and sandstone erosion, a transgressive sequence of red and purple Anhydrite shales was laid. Variegated bed remnants occur in crestal sections of many northern structures, such as
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the uppermost subdivision of the Early/Lower Cretaceous epoch/series, its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma. The Albian is followed by the Cenomanian; the Albian stage was first proposed in 1842 by Alcide d'Orbigny. It was named after Alba, the latin name for River Aube in France, A Global Boundary Stratotype Section and Point, ratified by the IUGS in 2016, defines the base of the Albian as the first occurrence of the planktonic foraminiferan Microhedbergella renilaevis at the Col de Pré-Guittard section, Arnayon, Drôme, France; the top of the Albian stage is defined as the place where the foram species Rotalipora globotruncanoides first appears in the stratigraphic column. The Albian is sometimes subdivided in Early/Lower and Late/Upper subages or substages. In western Europe in the UK, a subdivision in two substages is more used; the following representatives of the Albian stage are worthy of notice: the phosphorite beds of the Argonne and Bray areas in France.
Moffitites The following is a list of Ammonite genera whose fossils are geochronologically found first in lower Albian strata. These genera may survive into portions of the Albian stage, or into geological stages; this list should not be thought of in terms of the lifespan of the genera included. Aioloceras Anacleoniceras Anadesmoceras Anisoceras Arcthoplites Brancoceras Brewericeras Cleoniceras Cymahoplites Douvilleiceras Epileymeriella Eubranoceras Farnhamia Hoplites Kossmatella Labeceras Leconteites Lemuroceras Leymeriella Lyelliceras Neobibolites Otohoplites Oxytropidoceras Paracanthoplites Parasilesites Parengonoceras Plictetia Prohelicoceras Proleymeriella Prolyelliceras Protohoplites Pseudoleymeriella Pseudosonneratia Puzosia Puzosigella Rhytidohoplites Rossalites Silesitoides Sokolovites Sonneratia Tegoceras Tetrahoplites Tetrahoplitoides Zealandites The following is a list of Ammonite genera whose fossils are geochronologically found first in middle Albian strata; these genera may survive into portions of the Albian stage, or into geological stages.
This list should not be thought of in terms of the lifespan of the genera included. Anagaudryceras Anahoplites Astiericeras Dimorphoplites Dipoloceras Dipoloceroides Engonoceras Epihoplites Euhoplites Falciferella Falloticeras Gastroplites Hamitoides Hysteroceras Isohoplites Manuaniceras Mojsisoviczia Mortoniceras Ostlingoceras Protengonoceras Proturrilitoides Pseudhelicoceras Scaphamites Subarcthoplites Sulcohoplites Turrilitoides Venezoliceras Zuluscaphites The following is a list of Ammonite genera whose fossils are geochronologically found first in upper Albian strata; these genera may survive into portions of the Albian stage, or into geological stages. This list should not be thought of in terms of the lifespan of the genera included. Adkinsites Arestoceras Beudantiella Bhimaites Borissiakoceras Cainoceras Callihoplites Cantabrigites Cenisella Cottreauites Cyrtochilus Deiradoceras Diplasioceras Discohoplites Ellipsoceras Elobiceras Eogunnarites Eopachydiscus Eoscaphites Erioliceras Ficheuria Flickia Gaudryceras Gazdaganites Goodhallites Hemiptychoceras Hengestites Hypengonoceras Hyphoplites Idiohamites Karamaiceras Karamaites Koloceras Lechites Lepthoplites Lytodiscoides Mantelliceras Mariella Metengonoceras Myloceras Neogastroplites Neoharpoceras Neokentoceras Neophlycticeras Pachydesmoceras Paradolphia Paraturrilites Pervinquieria Plesiohamites Plesioturrilites Pleurohoplites Prohysteroceras Psilohamites Rusoceras Salaziceras Saltericeras Scaphites Schloenbachia Sciponoceras Semenovites Spathiceras Stoliczkaia Stomohamites Worthoceras Carinophylloceras Gradstein, F.
M.. G. & Smith, A. G.. Kennedy, W. J.. S.. A. & Caron, M.. D'Orbigny, A. C. V. M.. GeoWhen Database - Albian Mid-Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS Stratigraphic chart of the Lower Cretaceous, at the website of Norges Network of offshore records of geology and stratigraphy Albian Stage, Cretaceous Period in Hampshire