Jurassic
The Jurassic period was a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago to the beginning of the Cretaceous Period 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era known as the Age of Reptiles; the start of the period was marked by the major Triassic–Jurassic extinction event. Two other extinction events occurred during the period: the Pliensbachian-Toarcian extinction in the Early Jurassic, the Tithonian event at the end; the Jurassic period is divided into three epochs: Early and Late. In stratigraphy, the Jurassic is divided into the Lower Jurassic, Middle Jurassic, Upper Jurassic series of rock formations; the Jurassic is named after the Jura Mountains within the European Alps, where limestone strata from the period were first identified. By the beginning of the Jurassic, the supercontinent Pangaea had begun rifting into two landmasses: Laurasia to the north, Gondwana to the south; this created more coastlines and shifted the continental climate from dry to humid, many of the arid deserts of the Triassic were replaced by lush rainforests.
On land, the fauna transitioned from the Triassic fauna, dominated by both dinosauromorph and crocodylomorph archosaurs, to one dominated by dinosaurs alone. The first birds appeared during the Jurassic, having evolved from a branch of theropod dinosaurs. Other major events include the appearance of the earliest lizards, the evolution of therian mammals, including primitive placentals. Crocodilians made the transition from a terrestrial to an aquatic mode of life; the oceans were inhabited by marine reptiles such as ichthyosaurs and plesiosaurs, while pterosaurs were the dominant flying vertebrates. The chronostratigraphic term "Jurassic" is directly linked to the Jura Mountains, a mountain range following the course of the France–Switzerland border. During a tour of the region in 1795, Alexander von Humboldt recognized the limestone dominated mountain range of the Jura Mountains as a separate formation that had not been included in the established stratigraphic system defined by Abraham Gottlob Werner, he named it "Jura-Kalkstein" in 1799.
The name "Jura" is derived from the Celtic root *jor via Gaulish *iuris "wooded mountain", borrowed into Latin as a place name, evolved into Juria and Jura. The Jurassic period is divided into three epochs: Early and Late. In stratigraphy, the Jurassic is divided into the Lower Jurassic, Middle Jurassic, Upper Jurassic series of rock formations known as Lias and Malm in Europe; the separation of the term Jurassic into three sections originated with Leopold von Buch. The faunal stages from youngest to oldest are: During the early Jurassic period, the supercontinent Pangaea broke up into the northern supercontinent Laurasia and the southern supercontinent Gondwana; the Jurassic North Atlantic Ocean was narrow, while the South Atlantic did not open until the following Cretaceous period, when Gondwana itself rifted apart. The Tethys Sea closed, the Neotethys basin appeared. Climates were warm, with no evidence of a glacier having appeared; as in the Triassic, there was no land over either pole, no extensive ice caps existed.
The Jurassic geological record is good in western Europe, where extensive marine sequences indicate a time when much of that future landmass was submerged under shallow tropical seas. In contrast, the North American Jurassic record is the poorest of the Mesozoic, with few outcrops at the surface. Though the epicontinental Sundance Sea left marine deposits in parts of the northern plains of the United States and Canada during the late Jurassic, most exposed sediments from this period are continental, such as the alluvial deposits of the Morrison Formation; the Jurassic was a time of calcite sea geochemistry in which low-magnesium calcite was the primary inorganic marine precipitate of calcium carbonate. Carbonate hardgrounds were thus common, along with calcitic ooids, calcitic cements, invertebrate faunas with dominantly calcitic skeletons; the first of several massive batholiths were emplaced in the northern American cordillera beginning in the mid-Jurassic, marking the Nevadan orogeny. Important Jurassic exposures are found in Russia, South America, Japan and the United Kingdom.
In Africa, Early Jurassic strata are distributed in a similar fashion to Late Triassic beds, with more common outcrops in the south and less common fossil beds which are predominated by tracks to the north. As the Jurassic proceeded and more iconic groups of dinosaurs like sauropods and ornithopods proliferated in Africa. Middle Jurassic strata are neither well studied in Africa. Late Jurassic strata are poorly represented apart from the spectacular Tendaguru fauna in Tanzania; the Late Jurassic life of Tendaguru is similar to that found in western North America's Morrison Formation. During the Jurassic period, the primary vertebrates living in the sea were marine reptiles; the latter include ichthyosaurs, which were at the peak of their diversity, plesiosaurs and marine crocodiles of the families Teleosauridae and Metriorhynchidae. Numerous turtles could be found in rivers. In the invertebrate world, several new groups appeared, including rudists (a reef-formi
Animal
Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres and have complex interactions with each other and their environments, forming intricate food webs. The category includes humans, but in colloquial use the term animal refers only to non-human animals; the study of non-human animals is known as zoology. Most living animal species are in the Bilateria, a clade whose members have a bilaterally symmetric body plan; the Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes and molluscs—and the deuterostomes, containing the echinoderms and chordates.
Life forms interpreted. Many modern animal phyla became established in the fossil record as marine species during the Cambrian explosion which began around 542 million years ago. 6,331 groups of genes common to all living animals have been identified. Aristotle divided animals into those with those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between animal taxa. Humans make use of many other animal species for food, including meat and eggs. Dogs have been used in hunting, while many aquatic animals are hunted for sport.
Non-human animals have appeared in art from the earliest times and are featured in mythology and religion. The word "animal" comes from the Latin animalis, having soul or living being; the biological definition includes all members of the kingdom Animalia. In colloquial usage, as a consequence of anthropocentrism, the term animal is sometimes used nonscientifically to refer only to non-human animals. Animals have several characteristics. Animals are eukaryotic and multicellular, unlike bacteria, which are prokaryotic, unlike protists, which are eukaryotic but unicellular. Unlike plants and algae, which produce their own nutrients animals are heterotrophic, feeding on organic material and digesting it internally. With few exceptions, animals breathe oxygen and respire aerobically. All animals are motile during at least part of their life cycle, but some animals, such as sponges, corals and barnacles become sessile; the blastula is a stage in embryonic development, unique to most animals, allowing cells to be differentiated into specialised tissues and organs.
All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. During development, the animal extracellular matrix forms a flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible; this may be calcified, forming structures such as shells and spicules. In contrast, the cells of other multicellular organisms are held in place by cell walls, so develop by progressive growth. Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, desmosomes. With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues; these include muscles, which enable locomotion, nerve tissues, which transmit signals and coordinate the body. There is an internal digestive chamber with either one opening or two openings. Nearly all animals make use of some form of sexual reproduction, they produce haploid gametes by meiosis.
These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement, it first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm develops between them; these germ layers differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. In some species, such as the splendid fairywren, females benefit by mating with multiple males, thus producing more offspring of higher genetic quality; some animals are capable of asexual reproduction, which results
Johann Friedrich von Brandt
Johann Friedrich von Brandt was a German naturalist, who worked in Russia. Brandt was educated at a gymnasium in Wittenberg and the University of Berlin. In 1831 he emigrated to Russia, soon was appointed director of the Zoological Museum of the St Petersburg Academy of Sciences. Brandt encouraged the collection of native animals, many of which were not represented in the museum. Many specimens began to arrive from the expeditions of Severtzov, Middendorff and Gustav Radde, he described several birds collected by Russian explorers off the Pacific Coast of North America, including Brandt's cormorant, red-legged kittiwake and spectacled eider. As a paleontologist, Brandt ranks among the best, he was an entomologist, specialising in Coleoptera and Diplopoda. He died in Governorate of Estonia, he is commemorated in Brandt's bat, Brandt's hedgehog, three other species of mammals, the lizard Iranolacerta brandtii. In addition, Johann Friedrich von Brandt concerned the continuation of the work Getreue Darstellung und Beschreibung der in der Arzneykunde gebräuchlichen Gewächse of Friedrich Gottlob Hayne.
Flora Berolinensis, sive descriptio plantarum phanerogamarum circa Berolinum sponte crescentium vel in agris cultarum additis filicibus et charis Deutschlands phanerogamische Giftgewächse Tabellar Uebersichi d. offizin. Gewächse nach d. Linn. Sexualsystem u. d. natürl. System Medizinische Zoologie oder getreue Darstellung und Beschreibung der Thiere die in der Arzneimlttellehre in Betracht Kommen, 2 vols. Written with J. T. C. Ratzeburt Uebersicht d. Charactere d. Familien d. offizin. Gewächse nach R. Brown, De Candolle, Jussieu,… Deutschlands kryptogamische Giftgewächse Deutschlands phanerogamische Geftgewächse as Abbildung und Beschreibung der in Deutschland wild wachsenden und in Gärten in freien ausdauernden Giftgewächse, nach natürlichen Familien erläutert, mit Beiträgen von P. Phoebus und J. T. C. Ratzeburg Symbolae Sirenologicae quibus praecipue Rhutinae historia naturalis illustratur Symbolae Sirenologicae…, fasc. 2 and 3 Mémoires de l’Académie impériale des sciences, St. Pétersbourg, 7th ser.
12, no. 1. Fuchs, ibid. 20, no. 1 Ergänzungen, ibid. 21, no. 6 Bericht über die Fortschritte, welche die zoologischen Wissenschaften den von der kaiserlichen Akademie der Wissenschaften zu St. Petersburg von 1831 bis 1879 herausgegeben Schriften verdanken J. F. Brandtii index operum omnium, issued as a Festschrift. Getreue Darstellung und Beschreibung der in der Arzneykunde gebräuchlichen Gewächse wie auch solcher, welche mit ihnen verwechselt werden können. 12 Volumes, 1805–1856. Digital Edition by the University and State Library Düsseldorf Abbildung und Beschreibung der in Deutschland wild wachsenden und in Gärten im Freien ausdauernden Giftgewächse nach natürlichen Familien erläutert. Band 1: Phanerogamen Hirschwald, Berlin 1834 Digital edition by the University and State Library Düsseldorf Abbildung und Beschreibung der in Deutschland wild wachsenden und in Gärten im Freien ausdauernden Giftgewächse nach natürlichen Familien erläutert. Band 2: Kryptogamen Hirschwald, Berlin 1838 Digital edition by the University and State Library Düsseldorf Untersuchungen über die fossilen und subfossilen cetaceen Europa's.
Mémoires de L'Académie Impériale des Sciences de Saint-Petersbourg, Series 7 20:1-372 1873 Hemisyntrachelus Acipenser baerii Brandt, 1869 Acipenser guldenstadti Brandt & Ratzeburg, 1833 Acipenser schrenckii Brandt, 1869 Chrysaora Fuscescens Brandt, 1835 Emberiza bruniceps Brandt, 1841 Emberiza cioides Brandt, 1843 Holothuria leucospilota Brandt, 1835 Idotea ochotensis Brandt, 1851 Lasiopodomys brandtii Ligia dilatata Brandt, 1833 Metridium farcimen Brandt, 1835 Mesocricetus brandti Myotis brandtii Eversmann, 1845 Paraechinus hypomelas Phalacrocorax penicillatus Porphyrophora hamelii Brandt, 1833 Somateria fischeri Brandt, 1847 Stichopus chloronotus Brandt, 1835 Trionyx maackii Brandt, 1858 Anonym 1877 Das fünfzigjährige Doktorjubiläum des Akademikers Geheimrat Johann Friedrich Brandt am 12. Januar 1876. St. Petersburg. Anonym 1879 Botan. Ztg. 37 743 Anonym 1879: Naturaliste Canad. 1 111 Anonym 1879: Zool. Anz. 2 480 Medvedev, G. S. 2000 Trudy Russk. Ent. Obsc. 71 6-22, Portr. Ratzeburg, J. T. C. 1874 Forstwissenschaftliches Schriftsteller-Lexikon.
Berlin, Nicolai'sche Buchhandlung: X+1-516 72-76 Strauch, A. 1889 Das zoologische Museum der Kaiserlichen Akademie der Wissenschaften zu St. Petersburg in seinem fünfzigjährigen Bestehen. Works by Johann Friedrich von Brandt at Project Gutenberg Works by or about Johann Friedrich von Brandt at Internet Archive Brandt J. F. scanned books. Brandt, Johann Friedrich in Complete Dictionary of Scientific Biography
Gulf sturgeon
The Gulf sturgeon is a subspecies of sturgeon that lives in the Gulf of Mexico and some rivers draining into it. The Gulf sturgeon was first recognized as a separate subspecies in 1955; the nominate subspecies is the Atlantic sturgeon, A. o. oxyrinchus. The Gulf sturgeon is listed as threatened under the United States Endangered Species Act, having been listed in 1991. Critical habitat, reflecting the current range of the subspecies, has been designated; the historical range is thought to have been from the Suwannee River on the western coast of Florida to the Mississippi River, marine waters of the central and eastern portions of the Gulf of Mexico. Three sturgeon species in genus Scaphirhynchus share river territory with the Gulf sturgeon. Visually, Gulf sturgeon are impossible to differentiate from Atlantic sturgeon, as the most significant morphological difference is the spleen length, internal. Gulf sturgeon have a spleen length averaging 12.3% of their fork length, while Atlantic sturgeon have a spleen length averaging 5.7% of their fork length.
Lesser morphological differences include relative head length, shape of dorsal scutes, pectoral fin length. Genetic differences between the subspecies have been studied, tend to indicate reproductive isolation occurred in the Pleistocene period. Behavioral differences are more clear the dietary habits. Adult Gulf sturgeon eat or only, during the winter, when they are in marine or brackish water, eat little to nothing during the remainder of the year when they are in rivers, their weights vary in accordance with this eating pattern, with significant weight gains in the winter and smaller weight losses in the summer. Because their diet consists of mollusks that can cause paralytic shellfish poisoning, in addition to other bottom-dwelling organisms such as grass shrimp, marine worms and amphipods, their unique feeding pattern reflects an adaptation to prevent PSP that coincides with higher rates of algal blooms in summer. Juvenile Gulf sturgeon remain in the spawning river until two years of age, eating there.
Thereafter, they join the adults in their anadromous migrations and eating habits. The upriver migration occurs between February and April, as river temperatures rise to 16 to 23 °C. Downriver migration begins in late September or October when water temperatures drop to 23 °C. Males reach sexual maturity between seven and 12 years of age, females between eight and 17 years of age. Spawning always occurs in the natal river over a hard bottom just downstream of a spring on the river bottom feeding groundwater into the river. After spawning, the adults and older juveniles collect in regions of cooler, slower-flowing water downstream of springs. All species of sturgeon leap out of the water at times; the Gulf sturgeon tends to jump during July and August, again early during the offshore feeding period. They are thought to jump to maintain group cohesion. Due to their heavy body armor, large leaping sturgeon can inflict serious injuries to humans who are in the way. On July 2, 2015, a leaping sturgeon on the Suwannee River in Florida struck and killed a 5-year-old girl.
Predators of the sturgeon, other than humans, are unknown, but thought to have limited impact upon the species. Parasites include the fish louse Argulus stizostehi, nematodes and leeches. No detrimental impacts from these parasites have been observed; the species serves as host to the glochidia of three freshwater mussel species. Overfishing and dam construction contributed to the historical decline in populations. Froese and Daniel Pauly, eds.. "Acipenser oxyrinchus desotoi" in FishBase. February 2009 version. NOAA Fisheries gulf sturgeon web page
Beluga (sturgeon)
The beluga or European sturgeon is a species of anadromous fish in the sturgeon family of order Acipenseriformes. It is found in the Caspian and Black Sea basins, in the Adriatic Sea. Fished for the female's valuable roe—known as beluga caviar—the beluga is a huge and late-maturing fish that can live for about 118 years. Going on maximum size, it is the second most massive living species of bony fish behind the ocean sunfish; the species' numbers have been reduced by overfishing and poaching, prompting many governments to enact restrictions on its trade. The common name for the sturgeon, as for the unrelated beluga whale, is derived from the Russian word белый, meaning "white" referring to the extensive pale colour on the underside in beluga compared to other sturgeons; the beluga are a large predator which feeds on fish rarely consuming waterfowl and seal pups. The beluga will pursue prey in the pelagic zone unlike Acipenser sturgeons which remain more so in brackish areas for foraging, thus the beluga will pursue marine fish.
However much prey is taken in brackish areas such as river herrings, the asp and anchovies. Like most sturgeons, the beluga is anadromous, migrating upstream in rivers to spawn. Males attain sexual maturity at 12-16 years of age. In both sexes, they will go to spawn every 4 to 7 years. At one time, beluga sturgeons could migrate up to 1,000 km upriver to spawn but dams in every major tributary they utilize has impeded historic spawning routes; the female lays her eggs on gravel from 4 to 40 m underwater. Upon hatching, the embryo are 11 to 14 mm long, 10-14 days when they absorb their yolk sack, the length is 18 to 20 mm. Thereafter, the larvae subsist on benthic invertebrates but at as small as 10 cm in length will switch to a fish-based diet. While swimming back to the ocean, the young sturgeons may cover up to 60 km a day; the largest accepted record is of a female taken in 1827 in the Volga estuary at 1,571 kg and 7.2 m. Another specimen weighed 1,220 kg and measured 6.1 m in length. Several other records of aged sturgeon exceed 5 m.
These great sizes mark the beluga as the largest freshwater fish in the world. A few other species of sturgeon can attain great sizes but none match the maximum sizes known for the beluga, like Chinese, Pacific White, Oceanic European, Atlantic and Kaluga, the latter a close cousin which can attain a maximum weight of 1,000 kg, thus attaining the second largest known sturgeon size, it may be considered as a rival in size to the ocean sunfish among all extant bony fishes, although that passive marine giant has neither been nearly as fished nor takes as long to attain great size, so more attains massive weights. The beluga may be the second longest extant bony fish as well, after the giant oarfish, far more slender in build; the Beluga rivals the great white shark, the Greenland shark, the tiger shark for the title of largest predatory fish, with only the great white exceeding the beluga's maximum size. The giant belugas are much larger than the Mekong giant catfish, the arapaima or other sizable rivals for the title of largest freshwater fish.
Some scientists still consider the Mekong giant catfish to be the largest true freshwater fish, owing to sturgeons' ability to survive in seawater and that it spends much of its life in brackish environments. Beluga of such great sizes are old and have become rare in recent decades due to the heavy fishing of this species. Today, mature belugas that are caught are 142–328 cm long and weigh 19–264 kg; the female beluga is 20% larger than the male. An exceptionally big beluga caught reportedly weighed 960 kg and measured 3.4 m. Beluga caviar is considered a delicacy worldwide; the flesh of the beluga, though, is not renowned but is a hearty white meat similar to that of swordfish. Beluga caviar has long been scarce and expensive and its endangered status has made its caviar more expensive in worldwide markets outside of the United States, its air bladder is said to make the best isinglass. IUCN classifies the beluga as critically endangered, it is a protected species listed in appendix III of the Bern Convention, its trade is restricted under CITES appendix II.
The Mediterranean population is protected under appendix II of the Bern Convention, prohibiting any intentional killing of these fish. The United States Fish and Wildlife Service has banned imports of beluga caviar and other beluga products from the Caspian Sea since October 6, 2005, after listing beluga sturgeon under the U. S. Endangered Species Act. "Huso huso". Integrated Taxonomic Information System. Retrieved 24 January 2006. Annex II of the Convention on the Conservation of European Wildlife and Naturaabitats. Revised 1 March 2002
Adriatic sturgeon
The Adriatic sturgeon is a species of fish in the family Acipenseridae. It is native to the Adriatic Sea and large rivers in Albania, Greece, Italy and Slovenia. Specimens can be seen in several public aquarium, such the Milan Aquarium, Aquarium Finisterrae, Aquarium of the Po, Oasis of Sant'Alessio in Lombardy, it is an elongated fish that can grow to a maximum length of about 2 m, with an olive-brown back, paler flanks and whitish belly. This fish is threatened by habitat loss and overfishing the capture of immature fish that have not bred. Populations of the fish have dwindled and it seems to be no longer present in many of its previous habitats; the International Union for Conservation of Nature has rated its conservation status as "critically endangered", it is to be functionally extinct in the wild, as no spawning has been confirmed in recent years. However, it breeds in captivity and survives in commercial fish farms and captive breeding programs. One large specimen was caught, afterwards released, in the Po River in 2015.
The Adriatic sturgeon reaches a maximum weight of 25 kg. Like other sturgeons it has an elongated body, a flattened rostrum, a cartilaginous skeleton, distinctive bony scutes, an elongated upper lobe to its tail; the snout is broad and rounded, the lower lip has a central cleft and the four barbels are closer to the tip of the snout than they are to the mouth. The dorsal fin has no spines and 36 to 48 soft rays, the anal fin has 24 to 31 soft rays; the dorsal colouring is olive-brown, the flanks are the underside white. Like most sturgeon, the Adriatic sturgeon is an anadromous fish and can be found at different periods of its life in freshwater and marine environments, including estuaries and brackish water, it was to be found in the Adriatic Sea and the rivers flowing into it on either side. In 1932 its range in the sea was reported to be from Trieste to Greece and Corfu, it used to be present in the rivers Adige, Bacchiglione, Piave and Tagliamento. In the Po and its tributaries, it used to be present as far upstream as Turin.
It traditionally occurred in the Ticino and Adda rivers along the Albanian coasts, in the rivers of Croatia, Bosnia-Herzegovina and Montenegro, including Lake Skadar. It was reported from Greece in 1977 but is no longer found there, from Albania in 1997 in the Buna River, but has not been seen there since. Sturgeon are slow-growing, long-lived fish and do not reach sexual maturity until they are fifteen to twenty years old. After the young fish have spent a period of growth in estuaries and coastal waters, they spend most of their lives in large rivers, foraging on the bottom for crustaceans and small fish which they suck up with their toothless, funnel-like mouths. Mature fish move upstream in spring to spawn in clear-water, gravelly areas. Many of the traditional spawning areas are no longer available to them because of the impoundment of rivers, the only suitable remaining habitat for spawning is thought to be in the vicinity of the confluence of the River Po with its tributaries; the Adriatic sturgeon faces a number of threats such as pollution of rivers by industrial effluent and agricultural runoff and the fragmentation of their habitat by damming, which prevents them from moving upstream to suitable spawning areas.
They are caught or illegally and this is harmful when smaller fish are taken before they have reached maturity and reproduced at least once. They face competition from the wels catfish which has expanded its range into Western Europe; as they have become fewer in number they are affected by the Allee effect which postulates that a fish's growth rate is reduced at low population densities. No spawning has been observed in the wild for a number of years and the International Union for Conservation of Nature has rated the conservation status of this fish as "critically endangered" and "extinct in the wild". However, a number of organisations are concerned in attempts to preserve this species and a captive breeding scheme has been established, with young fish subsequently being released into the wild; the captive broodstock for this programme comprises about 25 individual fish. The Adriatic sturgeon is a tetraploid fish and research based on mitochondrial and microsatellite information is being done on the present breeding stock and other young fish to establish how best to increase the genetic diversity of the fish used in the breeding programme, because the current broodstock has been shown to retain only part of the genetic variation present in the original stock.
Despite the release of captive bred fish, no signs of spawning have been observed in the wild. In November 2015 a large specimen, estimated to be about 2 m long, was caught in the River Po near Ostiglia and released.
Pliocene
The Pliocene Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58 million years BP. It is the youngest epoch of the Neogene Period in the Cenozoic Era; the Pliocene is followed by the Pleistocene Epoch. Prior to the 2009 revision of the geologic time scale, which placed the four most recent major glaciations within the Pleistocene, the Pliocene included the Gelasian stage, which lasted from 2.588 to 1.806 million years ago, is now included in the Pleistocene. As with other older geologic periods, the geological strata that define the start and end are well identified but the exact dates of the start and end of the epoch are uncertain; the boundaries defining the Pliocene are not set at an identified worldwide event but rather at regional boundaries between the warmer Miocene and the cooler Pliocene. The upper boundary was set at the start of the Pleistocene glaciations. Charles Lyell gave the Pliocene its name in Principles of Geology; the word pliocene comes from the Greek words πλεῖον and καινός and means "continuation of the recent", referring to the modern marine mollusc fauna.
H. W. Fowler called the term Pliocene a "regrettable barbarism" and an indication that "a good classical scholar" such as Lyell should have requested a philologist's help when coining words. To summarize the usage of these "regrettable barbarisms" in the labelling of the Cenozoic era: with the understanding that these are all new relative to the Mesozoic and Paleozoic eras. In the official timescale of the ICS, the Pliocene is subdivided into two stages. From youngest to oldest they are: Piacenzian Zanclean The Piacenzian is sometimes referred to as the Late Pliocene, whereas the Zanclean is referred to as the Early Pliocene. In the system of North American Land Mammal Ages include Hemphillian, Blancan; the Blancan extends forward into the Pleistocene. South American Land Mammal Ages include Montehermosan and Uquian. In the Paratethys area the Pliocene contains the Romanian stages; as usual in stratigraphy, there are many other local subdivisions in use. In Britain the Pliocene is divided into the following stages: Gedgravian, Pre-Ludhamian, Thurnian, Bramertonian or Antian, Pre-Pastonian or Baventian and Beestonian.
In the Netherlands the Pliocene is divided into these stages: Brunssumian C, Reuverian A, Reuverian B, Reuverian C, Tiglian A, Tiglian B, Tiglian C1-4b, Tiglian C4c, Tiglian C5, Tiglian C6 and Eburonian. The exact correlations between these local stages and the ICS stages is still a matter of detail; the global average temperature in the mid-Pliocene was 2–3 °C higher than today, carbon dioxide levels were the same as today, global sea level was 25 m higher. The northern hemisphere ice sheet was ephemeral before the onset of extensive glaciation over Greenland that occurred in the late Pliocene around 3 Ma; the formation of an Arctic ice cap is signaled by an abrupt shift in oxygen isotope ratios and ice-rafted cobbles in the North Atlantic and North Pacific ocean beds. Mid-latitude glaciation was underway before the end of the epoch; the global cooling that occurred during the Pliocene may have spurred on the disappearance of forests and the spread of grasslands and savannas. Continents continued to drift, moving from positions as far as 250 km from their present locations to positions only 70 km from their current locations.
South America became linked to North America through the Isthmus of Panama during the Pliocene, making possible the Great American Interchange and bringing a nearly complete end to South America's distinctive large marsupial predator and native ungulate faunas. The formation of the Isthmus had major consequences on global temperatures, since warm equatorial ocean currents were cut off and an Atlantic cooling cycle began, with cold Arctic and Antarctic waters dropping temperatures in the now-isolated Atlantic Ocean. Africa's collision with Europe formed the Mediterranean Sea, cutting off the remnants of the Tethys Ocean; the border between the Miocene and the Pliocene is the time of the Messinian salinity crisis. Sea level changes exposed the land bridge between Asia. Pliocene marine rocks are well exposed in the Mediterranean and China. Elsewhere, they are exposed near shores. During the Pliocene parts of southern Norway and southern Sweden, near sea level rose. In Norway this rise elevated the Hardangervidda plateau to 1200 m in the Early Pliocene.
In Southern Sweden similar movements elevated the South Swedish highlands leading to a deflection of the ancient Eridanos river from its original path across south-central Sweden into a course south of Sweden. The change to a cooler, seasonal climate had considerable impacts on Pliocene vegetation, reducing tropical species worldwide. Deciduous forests proliferated, coniferous forests and tundra covered much of the north, grasslands spread on all continents. Tropical forests were limited to a tight band around the equator, in addition to dry savannahs, deserts appeared in Asia and Africa. Both marine and co
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