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Primoriella
''Primoriella'' is a genus of trilobite, an extinct group of marine arthropods. The only known species, ''P. bella'' occurs in the uppermost Lower Cambrian of Russia (''Redlichina culmenica'' beds, far eastern Siberia). It is related to ''Paradoxides'', but can be distinguished from it by only slightly forward expansion of the (glabella) a character shared with '' Anabaraceps'' and '' Schagonaria''. In ''Primoriella'' however, the front of the glabella touches the roll-like border, causing it to slightly bulge forward, while in ''Anabaraceps'' there is a roll-like preglabellar field as wide as the flat border in front of it. The glabella of ''Primordiella'' is less than twice as long as wide, and differs from ''Schagonaria'' in which it is more than twice as long as wide. The thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the tho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schagonaria
''Schagonaria'' is a genus of trilobite, an extinct group of marine arthropods. The only known species, ''S. tannuola'' occurs in the earliest Middle Cambrian of Russia (Amgaian, Ulukhema River, Tuva Region). It is related to ''Paradoxides'', but can be distinguished from it by only slightly forward expansion of the glabella, a character shared with '' Anabaraceps'' and ''Primoriella''. In ''Primoriella'' the front of the glabella touches the roll-like border, causing it to slightly bulge forward, in ''Anabaraceps'' there is a roll-like preglabellar field as wide as the flat border in front of it, but in ''Schagonaria'' the glabella may or may not touch the frontal border, but neither the border, nor if present the preglabellar field is particularly convex. The glabella of ''Schagonaria'' is more than twice as long as wide, and differs from ''Primordiella'' in which it is less than twice as long as wide. The articulate middle part of the body (or thorax The thorax or chest i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paradoxididae
The Paradoxididae are a family of trilobites, a group of extinct marine arthropods. They occurred during the late Lower Cambrian (Toyonian) and disappeared at the end of the Middle Cambrian. Representatives of this family have been found in the paleocontinents of Avalonia, Baltica, and Gondwana, now Canada (Nova-Scotia, New Brunswick, Newfoundland), USA (Massachusetts, South Carolina), England, Wales, Morocco, Spain, Czech Republic, Poland, Russia (Novaya Zemlya, Northern Siberia, North-East Yakutia), Mongolia, and Turkey. Species in this family can typically grow large to very large (over 30 cm), are relatively flat, have an inverted egg-shaped outline, opisthoparian sutures, a glabella that in early genera has parallel sides and expands forward in later representatives, and approaches or reaches the frontal border. All species have an almost semicircular headshield (or cephalon) with long backward-directed genal spines. The articulate middle part of the body (or thorax) co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lower Cambrian
The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Cambrian bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arthropod cuticle, cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an exoskeleton, external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior Organ (anatomy), organs; it has an open circulatory system. Like their exteriors, the internal or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paradoxidoidea
The Paradoxidoidea Hawle & Corda 1847,HAWLE, J. & CORDA, A. J. C. 1847. ''Prodrom einer Monographieder bohmischen Trilobiten''. 176 pp. J. G. Calve, Prague are a superfamily of trilobites, a group of extinct marine arthropods. They occurred during the late Lower Cambrian (Toyonian) and disappeared at the end of the Middle Cambrian. Description Species in this superfamily can be average (under 10 cm) to very large (over 30 cm), are relatively flat, have an inverted egg-shaped outline, a glabella that in early genera has parallel sides and expands forward in later representatives, and approaches or reaches the frontal border. All species have an almost semicircular headshield (or cephalon) with long backward directed genal spines. The facial suture in front of the eye diverges forward and outward in the Paradoxididae, while in the Centropleuridae it runs outward and even a bit backward (or retrodivergent). The articulate middle part of the body (or thorax) consists of 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Trilobites
The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Cambrian bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treatise On Invertebrate Paleontology
The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and extant (still living) invertebrate animals. The prehistoric invertebrates are described as to their taxonomy, morphology, paleoecology, stratigraphic and paleogeographic range. However, taxa with no fossil record whatsoever have just a very brief listing. Publication of the decades-long ''Treatise on Invertebrate Paleontology'' is a work-in-progress; and therefore it is not yet complete: For example, there is no volume yet published regarding the post-Paleozoic era caenogastropods (a molluscan group including the whelk and periwinkle). Furthermore, every so often, previously published volumes of the ''Treatise'' are revised. Evolution of the project Raymond C. Moor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paradoxides
''Paradoxides'' is a genus of large to very large trilobite found throughout the world during the Middle Cambrian period. One record-breaking specimen of ''Paradoxides davidis'', described by John William Salter in 1863, is . The cephalon was semicircular with free cheeks ending in long, narrow, recurved spines. Eyes were crescent shaped providing an almost 360° view, but only in the horizontal plane. Its elongate thorax was composed of 19-21 segments and adorned with longish, recurved pleural spines. Its pygidium was comparatively small. ''Paradoxides'' is a characteristic Middle-Cambrian trilobite of the 'Atlantic' (Avalonian) fauna. Avalonian rocks were deposited near a small continent called Avalonia in the Paleozoic Iapetus Ocean. Avalonian beds are now in a narrow strip along the East Coast of North America, and in Europe. Description The exoskeleton of ''Paradoxides'' is large to very large, relatively flat, and about one and a half times longer than wide, with greates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite
Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period () and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last extant trilobites finally disappeared in the mass extinction at the end of the Permian about 252 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described. By the time trilobites first appeared in the fossil record, they were already highly diversified and geographically dispersed. Because trilobites had wide diversity and an easily fossilized exoskeleton, they left an extensive fossil record. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Habitats
Marine habitats are habitats that support marine life. Marine life depends in some way on the saltwater that is in the sea (the term ''marine'' comes from the Latin ''mare'', meaning sea or ocean). A habitat is an ecological or environmental area inhabited by one or more living species.Abercrombie, M., Hickman, C.J. and Johnson, M.L. 1966.''A Dictionary of Biology.'' Penguin Reference Books, London The marine environment supports many kinds of these habitats. Marine habitats can be divided into coastal and open ocean habitats. Coastal habitats are found in the area that extends from as far as the tide comes in on the shoreline out to the edge of the continental shelf. Most marine life is found in coastal habitats, even though the shelf area occupies only seven percent of the total ocean area. Open ocean habitats are found in the deep ocean beyond the edge of the continental shelf. Alternatively, marine habitats can be divided into pelagic and demersal zones. Pelagic hab ... [...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] |
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