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Cephalopod Egg Fossil
Cephalopod egg fossils are the fossilized remains of eggs laid by cephalopods. The fossil record of cephalopod eggs is scant since their soft, gelatinous eggs decompose quickly and have little chance to fossilize. Eggs laid by ammonoids are the best known and only a few putative examples of these have been discovered. The best preserved of these were discovered in the Jurassic Kimmeridge Clay of England. Currently no belemnoid egg fossils have ever been discovered although this may be because scientists have not properly searched for them rather than an actual absence from the fossil record. Taphonomy Ammonite eggs in well-aerated sea bottoms probably would have quickly been broken down by scavengers and aerobic bacteria. Fossil evidence supports this general idea since swarms of hatchling ammonitellae fossils are known although there are no associated egg fossils. One of the eggs preserved in the Kimmeridge Clay ammonite egg cluster K1486 bears crystalline phosphate on its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aulacostephanidae - Aulacostephanus Yo
Aulacostephanidae is an extinct ammonoid cephalopod family belonging to the superfamily Perisphinctoidea. These fast-moving nektonic carnivores lived during the Upper Jurassic period, from the Oxfordian to Tithonian ages. Genera Genera within this family include: *''Aulacostephanus'' *''Pictonia'' *''Rasenia'' *''Ringsteadia ''Ringsteadia'' is a Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous ...'' References * JOHN K. WRIGHT The Aulacostephanidae (Ammonoidea) of the Oxfordian/Kimmeridgian boundary beds (Upper Jurassic) of southern England Ammonitida families Perisphinctoidea Jurassic ammonites Ammonites of Europe Kimmeridgian first appearances Late Jurassic extinctions {{ammonitina-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Living Chamber
The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the body whorl, or last whorl, is the most recently formed and largest whorl (or revolution) of a spiral or helical shell, terminating in the aperture. It is called the "body whorl" because most of the body of the soft parts of the animal fits into this whorl. The proportional size of the body whorl in gastropod shells differs greatly according to the actual shell morphology. For shells in which the rate of whorl expansion of each revolution around the axis is very high, the aperture and the body whorl are large, and the shell tends to be low spired. The shell of the abalone is a good example of this kind of shell. The opposite tendency can sometimes create a high spire with very little whorl increase per revolution. In these instances, e.g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lias Group
The Lias Group or Lias is a lithostratigraphic unit (a sequence of rock strata) found in a large area of western Europe, including the British Isles, the North Sea, the Low Countries and the north of Germany. It consists of marine limestones, shales, marls and clays. ''Lias'' is a Middle English term for hard limestone, used in this specific sense by geologists since 1833. In the past, geologists used ''Lias'' not only for the sequence of rock layers, but also for the timespan during which they were formed. It was thus an alternative name for the Early Jurassic epoch of the geologic timescale. It is now more specifically known that the Lias is Rhaetian to Toarcian in age (over a period of 20 million years between ) and thus also includes a part of the Triassic. The use of the name "Lias" for a unit of time is therefore slowly disappearing. Subdivisions In southern England, the Lias Group is often divided into Lower, Middle and Upper subgroups. In Southern England the Lias i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent 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, Aus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmophyllites
''Desmophyllites'' is a small desmoceratitid ammonite characterized by a smooth and very involute shell that lived during the Santonian to Maachstrictian stages of the Late Cretaceous. Shells of ''Desmophylites diphylloida'' from the upper Santonian are on order of 1.8 cm (0.7 in) in diameter. Those of ''Desmophylllites larteti'' from the upper Campanian are on order of 10.5 cm (~4 in) across. References * Arkell, et al, 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ..., Part L (L370-371). Geological Society of America. * ''Desmophyllites'' iDesmoceratinae {{Taxonbar, from=Q16466651 Cretaceous ammonites Ammonites of Europe Ammonitida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kamchatka
The Kamchatka Peninsula (, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and western coastlines, respectively. Immediately offshore along the Pacific coast of the peninsula runs the Kuril–Kamchatka Trench. The Kamchatka Peninsula, the Commander Islands, and Karaginsky Island constitute Kamchatka Krai of the Russia, Russian Federation. The majority of the 322,079 inhabitants are ethnic Russians, with about 13,000 being Koryaks (2014). More than half of the population lives in Petropavlovsk-Kamchatsky (179,526 in 2010) and nearby Yelizovo (38,980). The Kamchatka Peninsula contains the volcanoes of Kamchatka, a UNESCO World Heritage Site, that form part of the Ring of Fire. Geography Politically, the peninsula forms part of Kamchatka Krai. The southern tip is called Cape Lopatka. (Lopatka is Russian for spade.) The circular bay to the north of this on the Pacific side is Avac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is the first and shortest period of the Mesozoic Era and the seventh period of the Phanerozoic Eon. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anisian
In the geologic timescale, the Anisian is the lower stage (stratigraphy), stage or earliest geologic age, age of the Middle Triassic series (stratigraphy), series or geologic epoch, epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Epoch) and precedes the Ladinian Age. Stratigraphic definitions The stage and its name were established by Austrian geologists Wilhelm Heinrich Waagen and Carl Diener in 1895. The name comes from ''Anisus'', the Latin name of the river Enns (river), Enns. The original type locality (geology), type locality is at Großreifling in the states of Austria, Austrian state of Styria. The base of the Anisian Stage (also the base of the Middle Triassic series) is sometimes laid at the first appearance of conodont species ''Chiosella, Chiosella timorensis'' in the stratigraphic record. Other stratigraphers prefer to use the base of magnetic chronozone MT1n. There is no accept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total population of over 84 million in an area of , making it the most populous member state of the European Union. It 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 Capital of Germany, nation's capital and List of cities in Germany by population, most populous city is Berlin and its main financial centre is Frankfurt; the largest urban area is the Ruhr. Settlement in the territory of modern Germany began in the Lower Paleolithic, with various tribes inhabiting it from the Neolithic onward, chiefly the Celts. Various Germanic peoples, Germanic tribes have inhabited the northern parts of modern Germany since classical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muschelkalk
The Muschelkalk (German for "shell-bearing limestone"; ) is a sequence of sedimentary rock, sedimentary rock strata (a lithostratigraphy, lithostratigraphic unit) in the geology of central and western Europe. It has a Middle Triassic (240 to 230 million years) age and forms the middle part of the three-part Germanic Trias (that gives the Triassic its name) lying above the older Buntsandstein and below the younger Keuper. The Muschelkalk ("mussel-chalk") consists of a sequence of limestone and Dolomite (rock), dolomite Bed (geology), beds. In the past, the time span in which the Muschelkalk was deposited could also be called "Muschelkalk". In modern stratigraphy, however, the name only applies to the layers of rock. Occurrence The name ''Muschelkalk'' was first used by German geologist Georg Christian Füchsel (1722-1773). In 1834, Friedrich August von Alberti included it into the Triassic system (stratigraphy), system. The name indicates a characteristic feature of the unit, name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceratites
''Ceratites'' is an extinct genus of ammonite cephalopods. These nektonic carnivores lived in marine habitats in what is now Europe, during the Triassic, from the upper-most Anisian In the geologic timescale, the Anisian is the lower stage (stratigraphy), stage or earliest geologic age, age of the Middle Triassic series (stratigraphy), series or geologic epoch, epoch and lasted from million years ago until million years ag ... to the lower Ladinian age. Description This ammonite has a ceratitic suture pattern on its shell (smooth lobes and frilly saddles). Evolution of the frilly saddles is thought to be due to increased pressure on the shell, at greater depth. The frilly pattern would increase the strength of the shell and allow ''Ceratites'' to dive deeper, possibly in search of food. Distribution Fossils of this genus are only known from the Germanic Basin, which formed a partially isolated shallow sea across much of Europe from eastern France north of the future Alps an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macroconch
Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family Nautilidae). The earliest ammonoids appeared during the Emsian stage of the Early Devonian (410.62 million years ago), with the last species vanishing during or soon after the Cretaceous–Paleogene extinction event (66 million years ago). They are often called ammonites, which is most frequently used for members of the order Ammonitida, the only remaining group of ammonoids from the Jurassic up until their extinction. Ammonoids exhibited considerable diversity over their evolutionary history, with over 10,000 species having been described. Ammonoids are excellent index fossils, and they have been frequently used to link rock layers in which a particular species or genus is found to specific geologic time periods. Their fossil shells usual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
