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Belemnacanthus
''Belemnacanthus giganteus'' ("Gigantic arrow-spine") is a large, extinct, barrel-shaped holonematid arthrodire placoderm from Givetian-aged strata of Middle Devonian Eifel, Germany. ''B. giganteus'' is known only from the holotype, a portion of a median dorsal plate with a long, somewhat high, arching crest running down the median line of the exterior/dorsal side of the plate. The plate has an ornamentation of ridges that originate from a point posterior to the preserved portion of the median dorsal plate. Before the plate was identified as that of a holonematid, the plate of ''B. giganteus'' had been successively described as a tremendous spine of an elasmobranch, an agnathan, and lastly, the plate of an antiarch Antiarchi ("opposite anus") is an order of heavily armored placoderms. The antiarchs form the second-most successful group of placoderms after the arthrodires in terms of numbers of species and range of environments. The order's name was coi .... Reference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holonematidae
Holonematidae is an extinct family of relatively large arthrodire placoderms from the Early to Late Devonian. Almost all fossil specimens are of armor fragments, though, all have distinctive ornamentation, often of unique arrangements and patterns of tubercles, that are diagnostic of the family. The trunkshield is very elongated, giving the armor an overall "barrel" like appearance. Due to pebbles found inside articulated specimens of the Frasnian species, ''Holonema westolli'', holonematids are thought to have been specialized herbivores that grazed on a form of horn-shaped, stony algae called "onycholite," snipping off the tips with their odd snouts. Genera ''Artesonema'' A poorly known genus from the Givetian-aged Blacourt Formation of Boulonnais, France.LELIEVRE, n.; GOUJET, D., BLIECK, A. & JANVIER, P. 1986. ''Poissons du DEvonien du Boutonnais (France)''. - n:BRICE, D. d.Le DEvonien de Ferques, Bas -Boulonnais (N. France) - Biostratigraphie du PalEozoique 7: 503-522, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Givetian
The Givetian is one of two faunal stages in the Middle Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Eifelian Stage and followed by the Frasnian Stage. It is named after the town of Givet in France. The oldest forests occurred during the late Givetian. The lower GSSP is located at Jebel Mech Irdane, Tafilalt, Morocco. Name and definition The Givetian Stage was proposed in 1879 by French geologist Jules Gosselet Jules-Auguste Gosselet (19 April 1832 – 20 March 1916) was a French geologist born in Cambrai, France. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motility, able to move, can Sexual reproduction, reproduce sexually, and go through an ontogenetic stage in which their body consists of a hollow sphere of Cell (biology), cells, the blastula, during Embryogenesis, embryonic development. Over 1.5 million Extant taxon, living animal species have been Species description, described—of which around 1 million are Insecta, insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from to . They have Ecology, complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology. Most living animal species are in Bilateria, a clade whose members have a Symmetry in biology#Bilate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chordata
A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These five synapomorphies include a notochord, dorsal hollow nerve cord, endostyle or thyroid, pharyngeal slits, and a post-anal tail. The name “chordate” comes from the first of these synapomorphies, the notochord, which plays a significant role in chordate structure and movement. Chordates are also Bilateral symmetry, bilaterally symmetric, have a coelom, possess a circulatory system, and exhibit Metameric, metameric segmentation. In addition to the morphological characteristics used to define chordates, analysis of genome sequences has identified two conserved signature indels (CSIs) in their proteins: cyclophilin-like protein and mitochondrial inner membrane protease ATP23, which are exclusively shared by all vertebrates, tunicates and cep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrata
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates comprise such groups as the following: * jawless fish, which include hagfish and lampreys * jawed vertebrates, which include: ** cartilaginous fish (sharks, rays, and ratfish) ** bony vertebrates, which include: *** ray-fins (the majority of living bony fish) *** lobe-fins, which include: **** coelacanths and lungfish **** tetrapods (limbed vertebrates) Extant vertebrates range in size from the frog species ''Paedophryne amauensis'', at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placodermi
Placodermi (from Greek πλάξ 'plate' and δέρμα 'skin', literally 'Plate (animal anatomy), plate-skinned') is a Class (biology), class of armoured prehistoric fish, known from fossils, which lived from the Silurian to the end of the Devonian period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scale (zoology), scaled or naked, depending on the species. Placoderms were among the first jawed fish; their Fish jaw, jaws likely evolved from the first of their gill arches. Placoderms are thought to be paraphyly, paraphyletic, consisting of several distinct Outgroup (cladistics), outgroups or sister taxon, sister taxa to all living jawed vertebrates, which originated among their ranks. In contrast, one 2016 analysis concluded that placodermi are likely monophyletic, though these analyses have been further dismissed with more transitional taxa between placoderms and modern gnathosthomes, solidifying their paraphyletic status. Plac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthrodira
Arthrodira (Greek for "jointed neck") is an order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetrating most marine ecological niches. Arthrodires were the largest and most diverse of all groups of Placoderms. Description Arthrodire placoderms are notable for the movable joint between armor surrounding their heads and bodies. Like all placoderms, they lacked distinct teeth; instead, they used the sharpened edges of a bony plate on their jawbone as a biting surface. The eye sockets are protected by a bony ring, a feature shared by birds and some ichthyosaurs. Early arthrodires, such as the genus ''Arctolepis'', were well-armoured fishes with flattened bodies. The largest member of this group, ''Dunkleosteus'', was a true superpredator of the latest Devonian period, reaching as much as 6 m in length. In contrast, the long-nosed ''Rolfosteus'' measured just ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthrodire
Arthrodira (Greek for "jointed neck") is an Order (biology), order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetrating most marine ecological niches. Arthrodires were the largest and most diverse of all groups of Placoderms. Description Arthrodire placoderms are notable for the movable joint between armor surrounding their heads and bodies. Like all placoderms, they lacked distinct teeth; instead, they used the sharpened edges of a bony plate on their jawbone as a biting surface. The eye sockets are protected by a bony ring, a feature shared by birds and some ichthyosaurs. Early arthrodires, such as the genus ''Arctolepis'', were well-armoured fishes with flattened bodies. The largest member of this group, ''Dunkleosteus'', was a true superpredator of the latest Devonian period, reaching as much as 6 m in length. In contrast, the long-nosed ''Rolfosteus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eifel
The Eifel (; lb, Äifel, ) is a low mountain range in western Germany and eastern Belgium. It occupies parts of southwestern North Rhine-Westphalia, northwestern Rhineland-Palatinate and the southern area of the German-speaking Community of Belgium. The Eifel is part of the Rhenish Massif; within its northern portions lies the Eifel National Park. Geography Location The Eifel lies between the cities of Aachen to the north, Trier to the south and Koblenz to the east. It descends in the northeast along a line from Aachen via Düren to Bonn into the Lower Rhine Bay. In the east and south it is bounded by the valleys of the Rhine and the Moselle. To the west it transitions in Belgium and Luxembourg into the geologically related Ardennes and the Luxembourg Ösling. In the north it is limited by the Jülich-Zülpicher Börde. Within Germany it lies within the states of Rhineland-Palatinate and North Rhine-Westphalia; in the Benelux the area of Eupen, St. Vith and Luxemb ... [...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] |
