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Mortichnia
A mortichnia is the "death march", or last walk, of a living creature. These are sometimes preserved as fossil footprints. Notable examples In 2002 the mortichnia of a horseshoe crab was found in lithographic limestone in Bavaria, Germany. The trail measured 9.7m and was left about 150 million years ago when the crab died in an anoxic lagoon. The footprints left enough evidence for researchers to determine that the creature probably fell into the lagoon upside-down, righted itself, and started walking before succumbing to the anoxic conditions of the water. The trackway is currently exhibited at the Wyoming Dinosaur Center. See also * ''Kouphichnium'', an ichnogenus An ichnotaxon (plural ichnotaxa) is "a taxon based on the fossilized work of an organism", i.e. the non-human equivalent of an artifact. ''Ichnotaxa'' comes from the Greek ίχνος, ''ichnos'' meaning ''track'' and ταξις, ''taxis'' meaning ... attributed to horseshoe crabs References Walking Anoxic wate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kouphichnium
''Kouphichnium'' is an ichnogenus that has been attributed to limulids (horseshoe crabs). ''Kouphichnium'' fossils resemble the footprints of birds, sometimes in conjunction with a medial line, and were initially thought to be bird or pterosaur tracks. The footprints are now believed to be the imprints of specialized limulid appendages, called pushers, terminating in four plates, used to push against the sediment. The medial line is left by the animal's telson. This ichnogenus is registered in the Carboniferous to the Cretaceous, in marine marginal environments in Tennessee, the United States and in Poland, as well as non-marine environments of Argentina and England, among others.Aceñolaza, F. G., & Buatois, L. A. (1991). Trazas fósiles del Paleozoico superior continental argentino. Ameghiniana', 28, 89-108. The genus contains five species, ''K. arizonae'', ''K. cordifomnis'', ''K. lithographicum'', ''K. minusculum'' and ''K. walchi''. See also * List of xiphosuran genera * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anoxic Waters
Anoxic waters are areas of sea water, fresh water, or groundwater that are depleted of dissolved oxygen. The US Geological Survey defines anoxic groundwater as those with dissolved oxygen concentration of less than 0.5 milligrams per litre. Anoxic waters can be contrasted with hypoxic waters, which are low (but not lacking) in dissolved oxygen. This condition is generally found in areas that have restricted water exchange. In most cases, oxygen is prevented from reaching the deeper levels by a physical barrier, as well as by a pronounced density stratification, in which, for instance, heavier hypersaline waters rest at the bottom of a basin. Anoxic conditions will occur if the rate of oxidation of organic matter by bacteria is greater than the supply of dissolved oxygen. Anoxic waters are a natural phenomenon, and have occurred throughout geological history. The Permian–Triassic extinction event, a mass extinction of species from the world's oceans, may have resulted from w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesolimulus Walchi
''Mesolimulus'' is an extinct genus of horseshoe crab. The best known examples are found in Solnhofen limestone near Solnhofen, Bavaria, Germany. Originally assigned to the living genus ''Limulus'', they are related to and look virtually identical to modern horseshoe crabs. Other species assigned to ''Mesolimulus'' have been recorded spanning over 140 million years from the Middle Triassic to Late Cretaceous from England, Spain, Siberia and Morocco. Kouphichnium The unusual trackways left by these animals at Solnhofen were originally thought to have been made by birds or pterosaurs, since they included a cross-shaped marking comparable with the impression of a typical bird foot. Eventually they were correctly identified as arthropod footprints and named ''Kouphichnium walchi'', as proved by some remarkable 'death traces' showing a ''Mesolimulus'' circling round on itself before dying. The last leg of more advanced horseshoe crabs is modified into a so-called 'pusher' which co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jura Museum
The Jura Museum located in Willibaldsburg castle in the town of Eichstätt, Germany, is a natural history museum that has an extensive exhibit of Jurassic fossils from the quarries of Solnhofen and surroundings, including marine reptiles, pterosaurs, and one specimen of the early bird '' Archaeopteryx''. The latest acquisition of the museum is the well preserved skeleton of the coelurosaur ''Juravenator''. The museum also has an aquarium, with several large tanks showing tropical fish and corals, as well as ''Nautilus The nautilus (, ) is a pelagic marine mollusc of the cephalopod family Nautilidae. The nautilus is the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in ...''. External links Museum description Natural history museums in Germany Museums in Bavaria {{Bavaria-struct-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eichstätt
Eichstätt () is a town in the federal state of Bavaria, Germany, and capital of the district of Eichstätt. It is located on the Altmühl river and has a population of around 13,000. Eichstätt is also the seat of the Roman Catholic Diocese of Eichstätt. Geography Location Eichstätt lies on both sides of the river Altmühl in the district of Eichstätt of the Oberbayern region of Bavaria, in the heart of Altmühl Valley Nature Park. Geology Eichstätt is located in a valley of the Franconian Jura and is famous for the quarries of Solnhofen Plattenkalk (Jurassic limestone). On the Blumenberg the Berlin specimen of Archaeopteryx was found by Jakob Niemeyer. History St. Willibald founded the Diocese of Eichstätt on the site of an old Roman station ( or ) in 741. The city was given walls and chartered in 908. It was ruled by a prince-bishop, and in the Holy Roman Empire was the seat of the Bishopric of Eichstätt until secularization in 1802. In 1806, it became a part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Footprints
A fossil track or ichnite (Ancient Greek, Greek "''ιχνιον''" (''ichnion'') – a track, trace or footstep) is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism. Over the years, many ichnites have been found, around the world, giving important clues about the behaviour (and foot structure and stride) of the animals that made them. For instance, multiple ichnites of a single species, close together, suggest 'herd' or 'pack' behaviour of that species. Combinations of footprints of different species provide clues about the interactions of those species. Even a set of footprints of a single animal gives important clues, as to whether it was bipedal or quadrupedal. In this way, it has been suggested that some pterosaurs, when on the ground, used their forelimbs in an unexpected quadrupedal action. Special conditions are required, in order to preserve a footprint made in soft ground (such as an alluvi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horseshoe Crab
Horseshoe crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are chelicerates, most closely related to arachnids, such as spiders and scorpions. Horseshoe crabs live primarily in and around shallow coastal waters on soft, sandy or muddy bottoms. They are generally found in the intertidal zone at spring high tides. They are eaten in some parts of Asia, and used as fishing bait, in fertilizer and in science (especially ''Limulus'' amebocyte lysate). In recent years, population declines have occurred as a consequence of coastal habitat destruction and overharvesting. Tetrodotoxin may be present in one horseshoe crab species, '' Carcinoscorpius rotundicauda''. Fossil records for horseshoe crabs extend back as far as 480 million years ago, with extant forms being living fossils. A 2019 molecular analysis places them as the sister group of Ricinule ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithographic Limestone
Lithographic limestone is hard limestone that is sufficiently fine-grained, homogeneous and defect free to be used for lithography. Geologists use the term "lithographic texture" to refer to a grain size under 1/250 mm. The term "sublithographic" is sometimes used for homogeneous fine-grained limestone with a somewhat coarser texture. Origin The generally accepted theory for the origin of lithographic and sublithographic limestones is that they were formed in shallow, Stagnant water, stagnant, Hypersaline lake, hypersaline, and Anoxic waters, anoxic lagoons. The combination of mild hypersalinity and low oxygen content is believed to have inhibited the formation of microbial mats and prevented the invasion of bottom dwelling organisms. Microbial mats and bottom dwelling organisms would have left fossils, and bottom dwelling organisms would have churned the accumulating sediment, producing a less homogeneous rock. Stagnancy was required to avoid churning or sculpting of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bavaria
Bavaria ( ; ), officially the Free State of Bavaria (german: Freistaat Bayern, link=no ), is a state in the south-east of Germany. With an area of , Bavaria is the largest German state by land area, comprising roughly a fifth of the total land area of Germany. With over 13 million inhabitants, it is second in population only to North Rhine-Westphalia, but due to its large size its population density is below the German average. Bavaria's main cities are Munich (its capital and largest city and also the third largest city in Germany), Nuremberg, and Augsburg. The history of Bavaria includes its earliest settlement by Iron Age Celtic tribes, followed by the conquests of the Roman Empire in the 1st century BC, when the territory was incorporated into the provinces of Raetia and Noricum. It became the Duchy of Bavaria (a stem duchy) in the 6th century AD following the collapse of the Western Roman Empire. It was later incorporated into the Holy Roman Empire, became an ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated between the Baltic and North seas to the north, and the Alps to the south; it covers an area of , with a population of almost 84 million within its 16 constituent states. Germany borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The nation's capital and most populous city is Berlin and its financial centre is Frankfurt; the largest urban area is the Ruhr. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before AD 100. In 962, the Kingdom of Germany formed the bulk of the Holy Roman Empire. During the 16th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagoon
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') and ''atoll lagoons''. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries. Lagoons are common coastal features around many parts of the world. Definition and terminology Lagoons are shallow, often elongated bodies of water separated from a larger body of water by a shallow or exposed shoal, coral reef, or similar feature. Some authorities include fresh water bodies in the definition of "lagoon", while others explicitly restrict "lagoon" to bodies of water with some degree of salinity. The distinction between "lagoon" and "estuary" also varies between authorities. Richard A. Davis Jr. restrict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxia (environmental)
Hypoxia refers to low oxygen conditions. Normally, 20.9% of the gas in the atmosphere is oxygen. The partial pressure of oxygen in the atmosphere is 20.9% of the total barometric pressure. In water, oxygen levels are much lower, approximately 7 ppm or 0.0007% in good quality water, and fluctuate locally depending on the presence of photosynthetic organisms and relative distance to the surface (if there is more oxygen in the air, it will diffuse across the partial pressure gradient). Atmospheric hypoxia Atmospheric hypoxia occurs naturally at high altitudes. Total atmospheric pressure decreases as altitude increases, causing a lower partial pressure of oxygen, which is defined as hypobaric hypoxia. Oxygen remains at 20.9% of the total gas mixture, differing from hypoxic hypoxia, where the percentage of oxygen in the air (or blood) is decreased. This is common in the sealed burrows of some subterranean animals, such as blesmols. Atmospheric hypoxia is also the basis of altitude tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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