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Ehmaniella
''Ehmaniella'' is a genus of trilobite known from the Middle Cambrian Burgess Shale. 392 specimens of ''Ehmaniella'' are known from the Greater Phyllopod bed, where they comprise 0.74% of the community. Ehmaniella's major characteristics are a wide cranidium, heavy eye ridges, longitudinal striae on the pre-glabellar area, and a small pygidium The pygidium (plural pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is compo ... with few segments.Coppold, Murray and Wayne Powell (2006). ''A Geoscience Guide to the Burgess Shale'', p.56. The Burgess Shale Geoscience Foundation, Field, British Columbia. . References External links * Burgess Shale fossils Alokistocaridae Cambrian trilobites Cambrian genus extinctions {{Ptychopariida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alokistocaridae
Alokistocaridae is a family of ptychopariid trilobites that lived from the Botomian epoch of the Early Cambrian until the Late Cambrian. Alokistocarids were particle feeders and left small furrows which are occasionally preserved.Coppold, Murray and Wayne Powell (2006). ''A Geoscience Guide to the Burgess Shale'', p.54. The Burgess Shale Geoscience Foundation, Field, British Columbia. . Their remains are found worldwide. ''Elrathia kingii'', one of the most collected trilobites in the world, is a typical alokistocarid. Description Alokistocarids have an exoskeleton that is elongated ovate to inverted egg-shaped. The headshield (or cephalon) is semicircular and has a well-defined border. The central raised area of the cephalon (or glabella) is somewhat tapering forward, generally with 3 or 4 pairs of more or less distinct lateral furrows. The front of the glabella is rounded or truncate, and is separated from the border by a wide, moderately convex to flat (or rarely concave) so- ... [...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] |
Arthropoda
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] |
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. The stu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ptychopariida
Ptychopariida is a large, heterogeneous order of trilobite containing some of the most primitive species known. The earliest species occurred in the second half of the Lower Cambrian, and the last species did not survive the Ordovician–Silurian extinction event. Trilobites have facial sutures that run along the margin of the glabella and/or fixigena to the shoulder point where the cephalon meets the thorax. These sutures outline the cranidium, or the main, central part of the head that does not include the librigena (free cheeks). The eyes are medial along the glabella on the suture line (and some species have no eyes). The fossils of the moults of trilobites can often be told from the fossils of the actual animals by whether the librigena are present. (The librigena, or cheek spines, detach during moulting.) In ptychopariids, short bladelike genal spines are often present on the tips of the librigena. The thorax is large and is typically made up of eight or more segments. ... [...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. The stu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian
The Cambrian Period ( ; sometimes symbolized C with bar, 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 Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burgess Shale
The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (middle Cambrian), it is one of the earliest fossil beds containing soft-part imprints. The rock unit is a black shale and crops out at a number of localities near the town of Field in Yoho National Park Yoho National Park ( ) is a National Parks of Canada, national park of Canada. It is located within the Canadian Rockies, Rocky Mountains along the western slope of the Continental Divide of the Americas in southeastern British Columbia, bordered ... and the Kicking Horse Pass. Another outcrop is in Kootenay National Park 42 km to the south. History and significance The Burgess Shale was discovered by palaeontologist Charles Doolittle Walcott, Charles Walcott on 30 August 1909, towards the end of the season's fieldwork. He returned in 1910 with his sons, daughter, and wif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phyllopod Bed
The Phyllopod bed, designated by USNM locality number 35k, is the most famous fossil-bearing member of the Burgess Shale fossil ''Lagerstätte''. It was quarried by Charles Walcott from 1911–1917 (and later named Walcott Quarry), and was the source of 95% of the fossils he collected during this time; tens of thousands of soft-bodied fossils representing over 150 genera have been recovered from the Phyllopod bed alone. Stratigraphy and location The phyllopod bed is a 2.31 m thick layer of the 7 m thick Greater Phyllopod Bed, found in the Walcott Quarry on Fossil Ridge, between Wapta Mountain and Mount Field, at an elevation of around , around north of the railway town of Field, British Columbia, in the Canadian Rocky Mountains. It is adjacent to Mount Burgess, where Walcott first discovered the Burgess Shale formation. Walcott divided the bed into twelve units based on the rock type and fossil content. Certain fossil beds provide reference levels and can b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cranidium
''Cranidium''Westwood (1843) ''The Arcana Museum of Nature'' 2: 49. is an monotypic genus of stick insects The Phasmatodea (also known as Phasmida, Phasmatoptera or Spectra) are an order of insects whose members are variously known as stick insects, stick-bugs, walking sticks, stick animals, or bug sticks. They are also occasionally referred to as ... in the monotypic tribe Cranidiini. The single species ''Cranidium gibbosum'' has been recorded from northern Brazil, French Guiana and Surinam. References External Links * {{Taxonbar, from=Q14626032, from2=Q10461013 Phasmatodea genera Monotypic insect genera Phasmatodea of South America ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Striae
Stretch marks, also known as striae () or striae distensae, are a form of scarring on the skin with an off-color hue. Over time they may diminish, but will not disappear completely. Striae are caused by tearing of the dermis during periods of rapid growth of the body, such as during puberty or pregnancy, in which they usually form during the Pregnancy#Timeline, last trimester. Usually on the stomach, these striae also commonly occur on the breasts, thighs, hips, lower back, and buttocks. Pregnancy-related striae are known as ''striae gravidarum''. Striae may also be influenced by the Hormone, hormonal changes associated with puberty, pregnancy, bodybuilding, or hormone replacement therapy. There is no evidence that creams used during pregnancy prevent stretch marks. Once they have formed there is no clearly effective treatment, though various methods have been attempted and studied. Signs and symptoms Striae, or "stretch marks", begin as reddish or purple lesions, which can a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glabella
The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior to the nasion. Etymology The term for the area is derived from the Latin , meaning 'smooth, hairless'. In medical science The skin of the glabella may be used to measure skin turgor in suspected cases of dehydration by gently pinching and lifting it. When released, the glabella of a dehydrated patient tends to remain extended ("tented"), rather than returning to its normal shape. See also * Glabellar reflex The glabellar reflex, also known as the "glabellar tap sign", is a primitive reflex elicited by repetitive tapping of the the smooth part of the forehead above the nose and between the eyebrows. Subjects respond to the first several taps by blink ... References Bones of the head and neck {{musculoskeletal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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