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Amiskwia
''Amiskwia'' is a genus of soft-bodied animals known from fossils of the Middle Cambrian Lagerstätten both in the Burgess Shale in British Columbia, Canada and the Maotianshan shales of Yunnan Province, China. It is interpreted as a member of the clade Gnathifera ''sensu lato.'' Description Known specimens of ''Amiskwia'' vary in length from and in width from . The body was somewhat flattened. The head had a pair of tentacles that emerged from the midline of the head. The tentacles had a relatively thick base and tapered to a point. Along the sides of the trunk were a pair of lateral fins, which were around one third of the total body length. The trunk terminated with a flat, rounded caudal fin. The gut was straight, and ran from the mouth to the anus, which was located on the underside of the body near the caudal fin. Within the mouth is a pair of semi-circular structures, described as "jaws" each bearing 8-10 conical spikes, which increased in size away from the midline of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amiskwia Sagittiformis Diagram (cropped)
''Amiskwia'' is a genus of soft-bodied animals known from fossils of the Middle Cambrian Lagerstätten both in the Burgess Shale in British Columbia, Canada and the Maotianshan shales of Yunnan Province, China. It is interpreted as a member of the clade Gnathifera ''sensu lato.'' Description Known specimens of ''Amiskwia'' vary in length from and in width from . The body was somewhat flattened. The head had a pair of tentacles that emerged from the midline of the head. The tentacles had a relatively thick base and tapered to a point. Along the sides of the trunk were a pair of lateral fins, which were around one third of the total body length. The trunk terminated with a flat, rounded caudal fin. The gut was straight, and ran from the mouth to the anus, which was located on the underside of the body near the caudal fin. Within the mouth is a pair of semi-circular structures, described as "jaws" each bearing 8-10 conical spikes, which increased in size away from the midline of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnathifera (clade)
Gnathifera (from the Greek '' gnáthos'', “jaw”, and the Latin '' -fera'', “bearing”) is a clade of generally small spiralians characterized by complex jaws made of chitin. It comprises the phyla Gnathostomulida, Rotifera, Micrognathozoa, and Chaetognatha. It may also include the Cycliophora. Gnathiferans include some of the most abundant phyla. Rotifers are among the most diverse and abundant freshwater animals and chaetognaths are among the most abundant marine plankton. Description The most distinctive characteristic of gnathiferans is the presence of complex sclerotized mouthparts made of chitin. In most gnathiferans, the anus opens on the dorsal surface of the animal. In micrognathozoans and gnathostomulids, the anus is transient and only forms during defecation. Unlike other gnathiferans, in chaetognaths and '' Amiskwia'' the anus is located on the ventral surface in a subterminal position. Development All known gnathiferans are direct developers. Though gnathi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nemertea
Nemertea is a phylum of animals also known as ribbon worms or proboscis worms, consisting of 1300 known species. Most ribbon worms are very slim, usually only a few millimeters wide, although a few have relatively short but wide bodies. Many have patterns of yellow, orange, red and green coloration. The foregut, stomach and intestine run a little below the midline of the body, the anus is at the tip of the tail, and the mouth is under the front. A little above the gut is the rhynchocoel, a cavity which mostly runs above the midline and ends a little short of the rear of the body. All species have a proboscis which lies in the rhynchocoel when inactive but everts to emerge just above the mouth to capture the animal's prey with venom. A highly extensible muscle in the back of the rhynchocoel pulls the proboscis in when an attack ends. A few species with stubby bodies filter feed and have suckers at the front and back ends, with which they attach to a host. The brain is a rin ... [...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] |
Chaetognath
The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, about 20% of the known Chaetognatha species are benthic, and can attach to algae and rocks. They are found in all marine waters, from surface tropical waters and shallow tide pools to the deep sea and polar regions. Most chaetognaths are transparent and are torpedo shaped, but some deep-sea species are orange. They range in size from . There are more than 120 modern species assigned to over 20 genera. Despite the limited diversity of species, the number of individuals is large. Arrow worms are usually considered a type of protostome that do not belong to either Ecdysozoa or Lophotrochozoa. Anatomy Chaetognaths are transparent or translucent dart-shaped animals covered by a cuticle. The body is divided into a distinct head, trunk, and tail. There are between four and fourteen hooked, grasping spines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enigmatic Prehistoric Animal Genera
Enigmatic is an adjective meaning "mysterious" or "puzzling". It may also refer to: * ''Enigmatic'', a 1970 album by Czesław Niemen * '' Enigmatic: Calling'', a 2005 album by Norwegian progressive metal band Pagan's Mind * Enigmatic scale, musical scale used by Verdi and others * "The Enigmatic", a song by Joe Satriani on the album '' Not of This Earth'' See also * Enigmatic leaf turtle, a species of Asian leaf turtle * Enigmatic moray eel, a species found in the Pacific and Indian Oceans * ''Glaresis ''Glaresis'' is a genus of beetles, sometimes called "Enigmatic scarab beetles", in its own family, the Glaresidae. It is closely related to, and was formerly included in, the family Scarabaeidae. Although its members occur in arid and sandy area ...'', a genus of beetles sometimes called "enigmatic scarab beetles" * Enigma (other) {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burgess Shale Fossils
The fossils of the Burgess Shale, like the Burgess Shale itself, formed around 505 million years ago in the Mid Cambrian period. They were discovered in Canada in 1886, and Charles Doolittle Walcott collected over 65,000 specimens in a series of field trips up to the alpine site from 1909 to 1924. After a period of neglect from the 1930s to the early 1960s, new excavations and re-examinations of Walcott's collection continue to reveal new species, and statistical analysis suggests that additional discoveries will continue for the foreseeable future. Stephen Jay Gould's book '' Wonderful Life'' describes the history of discovery up to the early 1980s, although his analysis of the implications for evolution has been contested. The fossil beds are in a series of shale layers, averaging and totalling about in thickness. These layers were deposited against the face of a high undersea limestone cliff. All these features were later raised up above current sea level during the cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Invertebrates
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 biol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amiskwi River
The Amiskwi River is a stream of about in length in British Columbia, Canada. It is a tributary of the Kicking Horse River. The name ''Amiskwi'' is a Cree word for ''Beavertail''. Just as there is an Otterhead River and an Ottertail River (both of which join the Kicking Horse downstream from the Amiskwi), there is also a Beaverfoot River (also a Kicking Horse River tributary) to go with the ''Beavertail River'', which is an old name for the Amiskwi. Another old name of the river is the ''North Branch Kicking Horse River''. Course The Amiskwi River is the longest tributary of the Kicking Horse River, beginning at ''Amiskwi Pass'' and flowing south for about then southeast for about until its confluence with the Kicking Horse River at almost exactly the same location as the mouth of the Emerald River. A decommissioned logging road follows the lower course of the Amiskwi from the Emerald River and is presently an unmaintained hiking trail to Amiskwi Pass and a segmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnathostomulid
Gnathostomulids, or jaw worms, are a small phylum of nearly microscopic marine animals. They inhabit sand and mud beneath shallow coastal waters and can survive in relatively anoxic environments. They were first recognised and described in 1956. Anatomy Most gnathostomulids measure in length. They are often slender to thread-like worms, with a generally transparent body. In many Bursovaginoidea, one of the major group of gnathostomulids, the neck region is slightly narrower than the rest of the body, giving them a distinct head. Like flatworms they have a ciliated epidermis, but in contrast to flatworms, they have one cilium per cell. The cilia allow the worms to glide along in the water between sand grains, although they also use muscles, allowing the body to twist or contract, for movement. They have no body cavity, and no circulatory or respiratory system. The nervous system is simple, and restricted to the outer layers of the body wall. The only sense organs are modified c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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