|
Perspicaris
''Perspicaris'' (from the Latin ''perspicax'', meaning “sharp-sighted,” and ''caris'', “crab/shrimp”) an extinct genus of bivalved arthropod from the Cambrian period. Fossils have been found in North America, primarily the Burgess Shale of British Columbia, Canada but also possibly the Wheeler Shale, Marjum Formation, Pioche Shale and Bloomington Formation. Two named species are known from the Burgess Shale ''Perspicaris dictynna'' and ''Perspicaris recondita'', which differ in maximum size ( in ''P. recondita'' vs in ''P. dictynna''), as well as proportions of the tail. Both species have a pair of stalked eyes, as well as a pair of large segmented antennae. The tail is forked and spiny. They are thought to have been active swimmers (nektonic). ''Perspicaris'' has been identified as a member of a clade Hymenocarina close to the crown-group of Euarthropoda Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perspicaris
''Perspicaris'' (from the Latin ''perspicax'', meaning “sharp-sighted,” and ''caris'', “crab/shrimp”) an extinct genus of bivalved arthropod from the Cambrian period. Fossils have been found in North America, primarily the Burgess Shale of British Columbia, Canada but also possibly the Wheeler Shale, Marjum Formation, Pioche Shale and Bloomington Formation. Two named species are known from the Burgess Shale ''Perspicaris dictynna'' and ''Perspicaris recondita'', which differ in maximum size ( in ''P. recondita'' vs in ''P. dictynna''), as well as proportions of the tail. Both species have a pair of stalked eyes, as well as a pair of large segmented antennae. The tail is forked and spiny. They are thought to have been active swimmers (nektonic). ''Perspicaris'' has been identified as a member of a clade Hymenocarina close to the crown-group of Euarthropoda Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hymenocarina
Hymenocarina is an order of extinct arthropods known from the Cambrian. They possess bivalved carapaces, typically with exposed posteriors. Members of the group are morphologically diverse and had a variety of ecologies, including as filter feeders and as predators. Recent research has generally considered them to be stem or crown group members of Mandibulata, due the presence of mandibles in at least some species. Taxonomy Hymenocarines are characterized by the combination of following characters: bivalved, convex carapace covering cephalothoracic region; cephalothorax bearing multisegmented antennules and rounded mandibles, alongside post-maxillular limbs with spiny, subdivided basis and endopods with well-developed terminal claws; absence of appendages between antennules and mandibles; median sclerite and lobate protrusions located between compound eyes; posterior tagma (abdomen) with ring-like segments and terminated by a pair of well-developed caudal rami. Based on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wheeler Shale
The Wheeler Shale (named by Charles Walcott) is a Cambrian ( 507 Ma) fossil locality world-famous for prolific agnostid and ''Elrathia kingii'' trilobite remains (even though many areas are barren of fossils) and represents a Konzentrat-Lagerstätte. Varied soft bodied organisms are locally preserved, a fauna (including ''Naraoia'', ''Wiwaxia'' and ''Hallucigenia'') and preservation style (carbonaceous film) normally associated with the more famous Burgess Shale. As such, the Wheeler Shale also represents a Konservat-Lagerstätten. Together with the Marjum Formation and lower Weeks Formation, the Wheeler Shale forms of limestone and shale exposed in one of the thickest, most fossiliferous and best exposed sequences of Middle Cambrian rocks in North America. At the type locality of Wheeler Amphitheater, House Range, Millard County, western Utah, the Wheeler Shale consists of a heterogeneous succession of highly calcareous shale, shaley limestone, mudstone and thi ... [...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] |
Bloomington Formation
Bloomington may refer to: Places U.S.A. (most commonly) * Bloomington, Illinois *Bloomington, Indiana * Bloomington, Minnesota U.S.A. (less commonly) * Bloomington, California * Bloomington, Idaho * Bloomington, Kansas *Bloomington, Maryland * Bloomington, Missouri * Bloomington, Nebraska * Bloomington, New York * Bloomington, Ohio * Bloomington, South Dakota *Bloomington, Texas * Bloomington, Utah *Bloomington (Louisa, Virginia), a historic house * Bloomington, Wisconsin *Bloomington (town), Wisconsin * Bloomington Township, McLean County, Illinois * Bloomington Township, Indiana *Bloomington Township, Decatur County, Iowa *Bloomington Township, Muscatine County, Iowa *Bloomington Township, Kansas *Bloomington Township, Minnesota *Bloomington Township, Missouri *New Bloomington, Ohio Canada *Bloomington, Nova Scotia * Bloomington, Stormont-Dundas-Glengarry, Ontario *Bloomington, York Region, Ontario Bloomington is a hamlet in York Region, Ontario, Canada, in the town of Whitc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Arthropod Genera
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...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] |
Euarthropoda
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often 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 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 organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system is "ladder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nekton
Nekton or necton (from the ) refers to the actively swimming aquatic organisms in a body of water. The term was proposed by German biologist Ernst Haeckel to differentiate between the active swimmers in a body of water, and the passive organisms that were carried along by the current, the plankton. As a guideline, nektonic organisms have a high Reynolds number (greater than 1000) and planktonic organisms a low one (less than 10). However, some organisms can begin life as plankton and transition to nekton later on in life, sometimes making distinction difficult when attempting to classify certain plankton-to-nekton species as one or the other. For this reason, some biologists choose not to use this term. History The term was first proposed and used by the German biologist Ernst Haeckel in 1891 in his article ''Plankton-Studien'' where he contrasted it with plankton, the aggregate of passively floating, drifting, or somewhat motile organisms present in a body of water, primarily t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marjum Formation
The Marjum Formation is a Cambrian geological formation that overlies the Wheeler Shale in the House Range, Utah. It is known for its occasional preservation of soft-bodied tissue, and is slightly younger than the 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 fo ..., falling in the '' Ptychagnostus praecurrens'' trilobite zone. References {{reflist Cambrian geology of Utah Cambrian southern paleotropical deposits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pioche Shale
The Pioche Shale is an Early to Middle Cambrian Burgess shale-type Lagerstätte in Nevada. It spans the Early–Middle Cambrian boundary; fossils from the Early Cambrian are preserved in botryoidal hematite, whereas those from the Middle Cambrian are preserved in the more familiar carbon films, and very reminiscent of the Chengjiang County preservation. It preserves arthropods and worms familiar from the Burgess Shale. It spans the early Cambrian ''Olenellus'' and basal Middle Cambrian ''Eokochaspis nodosa'' trilobite zones. The eastern version of this shale can be found eastwards in Grand Canyon, as the Bright Angel Shale.Geology graphic of Pioche Shale & Bright Angel Shale at 3dpards.wr.usgs.go/ref> References External linksGraphic of geology of area west-to-eastfor Lake Mead National Recreation Area Lake Mead National Recreation Area is a U.S. national recreation area in southeastern Nevada and northwestern Arizona. Operated by the National Park Service, Lake Mead ... [...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] |
