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Naraoiidae
Naraoiidae is a family, of extinct, soft-shelled trilobite-like arthropods, that belongs to the order Nektaspida. Species included in the Naraoiidae are known from the second half of the Lower Cambrian to the end of the Upper Silurian. The total number of collection sites is limited and distributed over a vast period of time: Maotianshan Shale and Balang Formation (China), Burgess Shale and Bertie Formation (Canada), the Šárka Formation (Czech Republic), Emu Bay Shale (Australia), Idaho and Utah (USA). This is probably due to the rare occurrence of the right circumstances for soft tissue preservation, needed for these non-calcified exoskeletons. Ecology Naraoiids probably were deposit feeders (''Naraoia'' and '' Pseudonaraoia''), predators or scavengers (''Misszhouia''), living on the sea floor. Description The species of the family ''Naraoiidae'' are almost flat (dorso-ventrally). The upper (or dorsal) side of the body consists of a non-calcified transversely oval or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nektaspida
Nektaspida (also called Naraoiida, Nektaspia and Nectaspida) is an extinct order of non- mineralised artiopodan arthropods. They are known from the lower-Cambrian to the upper Silurian. Originally classified as trilobites, which they superficially resemble, they are now placed as close relatives as members of the Trilobitomorpha within Artiopoda. The order is divided into three major families; Emucarididae, Liwiidae, and Naraoiidae. Naming history and taxonomic placement The order was originally proposed by Raymond in 1920 as Nektaspia. Størmer corrected it to Nectaspida for the 1959 ''Treatise on Invertebrate Paleontology'' to conform with the names of the other trilobite orders. Whittington described it in 1985 with the spelling Nektaspida; the revised 1997 Treatise by Raymond and Fortey uses this spelling, as do other modern works. Whittington (1985) placed the order in the Trilobita. Cotton & Braddy (2000) place it in a new "Trilobite clade" containing the Trilobita, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudonaraoia
''Pseudonaraoia'' is a genus of small (about long) marine arthropods within the family Naraoiidae, that lived during the late Middle Ordovician period (or Darriwillian epoch). The only species presently known is ''Pseudonaraoia hammanni'' (the genus is monotypic). Etymology The genus name indicates the likeness to the related genus Naraoia. The species was named in honor of Dr. Wolfgang Hammann (†2002), the outstanding German palaeontologist who studied both trilobites and naraoids. Description ''P. hammanni'' is almost flat (dorso-ventrally). The upper (or dorsal) side of the body consists of a non-calcified headshield (cephalon) and tailshield (pygidium) of about equal length, without any body segments in between. The body is strongly narrowed at the articulation between cephalon and pygidium. Both shields have a narrow border, reminiscent of some effaced agnostid trilobites Trilobites (; meaning "three-lobed entities") are extinct marine arthropods that form the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Misszhouia
''Misszhouia'' is a genus of small to average sized (up to long) marine trilobite-like arthropods within the Naraoiidae family, that lived during the early Cambrian period. The species are ''M. longicaudata'', from the Maotianshan Shales, described in 1985, and ''M. canadensis'', from the Burgess Shale and described in 2018, although later species may belongs to genus ''Naraoia'' instead. Etymology ''Misszhouia'' was named after "Miss Zhou" (Zhou Guiqin), to honour her for her skilled preparation of Chengjiang fossils. Description ''Misszhouia longicaudata'' is almost flat (dorso-ventrally). The upper (or dorsal) side of the body consists of a non-calcified headshield (cephalon) and tailshield (pygidium) without body segments between. The body is narrowed at the articulation between cephalon and pygidium. The long many-segmented antennae are directed forward. There are no eyes. The gut has a relatively small diameter, and there are four pairs of relatively small digestive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naraoia
''Naraoia'' is a genus of small-to-average-size (about long) marine arthropods within the family Naraoiidae, that lived from the early Cambrian to the late Silurian period. The species are characterized by a large alimentary system and sideways oriented antennas. Etymology The name is derived from Narao, the name of a group of small lakes in Cataract Brook canyon, above Hector on the Canadian Pacific Railway, British Columbia, Canada.Walcott, C.D. Middle Cambrian Branchiopoda, Malacostraca, Trilobita, and Merostomata. In: Cambrian Geology and Paleontology II. Smithsonian. 1914. s:Cambrian Geology and Paleontology/Volume 2/Middle Cambrian Branchiopoda, Malacostraca, Trilobita, and Merostomata History of the classification When the fossil was first discovered in Canada's Burgess Shale, it was believed to be a crustacean, such was the difference between this and other trilobites. Its continuous shield hid most of its structure, interfering with proper classification. When Harr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atdabanian
Cambrian Stage 3 is the still unnamed third stage of the Cambrian. It succeeds Cambrian Stage 2 and precedes Cambrian Stage 4, although neither its base nor top have been formally defined. The plan is for its lower boundary to correspond approximately to the first appearance of trilobites, about million years ago, though the globally asynchronous appearance of trilobites warrants the use of a separate, globally synchronous marker to define the base. The upper boundary and beginning of Cambrian Stage 4 is informally defined as the first appearance of the trilobite genera '' Olenellus'' or '' Redlichia'' around million years ago. Naming The International Commission on Stratigraphy has not officially named the 3rd stage of the Cambrian. The stage approximately corresponds to the "Atdabanian", which is used by geologists working in Siberia. Biostratigraphy The oldest trilobite known is '' Lemdadella'' which appears at the beginning of the '' Fallotaspis'' zone. The Cambrian radi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deposit Feeder
Detritivores (also known as detrivores, detritophages, detritus feeders or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, vertebrates, and plants that eat detritus or carry out coprophagy. By doing so, all these detritivores contribute to decomposition and the nutrient cycles. Detritivores should be distinguished from other decomposers, such as many species of bacteria, fungi and protists, which are unable to ingest discrete lumps of matter. Instead, these other decomposers live by absorbing and metabolizing on a molecular scale (saprotrophic nutrition). The terms ''detritivore'' and ''decomposer'' are often used interchangeably, but they describe different organisms. Detritivores are usually arthropods and help in the process of remineralization. Detritivores perform the first stage of remineralization, by fragmenting the dead plant matter, allowing decompo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terreneuvian First Appearances
The Terreneuvian is the lowermost and oldest series of the Cambrian geological system. Its base is defined by the first appearance datum of the trace fossil ''Treptichnus pedum'' around million years ago. Its top is defined as the first appearance of trilobites in the stratigraphic record around million years ago. This series' name was formally accepted by the International Commission on Stratigraphy in 2007. The Fortunian stage and presently unnamed Cambrian Stage 2 are the stages within this series. The Terreneuvian corresponds to the pre- trilobitic Cambrian. The name Terreneuvian is derived from ''Terre Neuve'', the French name for the island of Newfoundland, Canada, where many rocks of this age are found, including the type section. GSSP The type locality (GSSP) of the Terreneuvian is in Fortune Head, at the northern edge of the Burin Peninsula, Newfoundland, Canada (). The outcrops show a carbonate-siliciclastic succession which is mapped as the Chapel Island Formatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxon
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion, especially in the context of rank-based (" Linnaean") nomenclature (much less so under phylogenetic nomenclature). If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were presumably set forth in prehistoric times by hunter-gatherers, as suggested by the fairly sophisticated folk taxonomies. Much later, Aristotle, and later st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobita
Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolution, evolutionary biology, and plate tectonics. Trilobites are placed within the clade Artiopoda, which includes many organisms that are morphologically similar to trilobites, but are largely unmineralised. The relationship of Artiopoda to other arthropods is uncertain. Trilobites evolved into many ecological niches; some moved over the seabed as predators, scavengers, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liwiidae
Liwiidae is a family of arthropods in the order Nektaspida. Members are known from the Cambrian and Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ... periods. Taxonomy *'' Liwia'' Dzik and Lendzion, 1988 :*'' Liwia plana'' Lendzion, 1975 :*'' Liwia convexa'' Lendzion, 1975 *'' Soomaspis'' Fortey & Theron, 1995 :*'' Soomaspis splendida'' Fortey & Theron, 1995 *'' Tariccoia'' Hammann ''et al.'', 1990 :*'' Tariccoia arrusensis'' Hammann ''et al.'', 1990 References Nektaspida Prehistoric arthropod families Cambrian first appearances Ordovician first appearances {{nektaspida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gills
A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia (: branchiae) is the zoologists' name for gills (from Ancient Greek ). With the exception of some aquatic insects, the filaments and lamellae (folds) contain blood or coelomic fluid, from which gases are exchanged through the thin walls. The blood carries oxygen to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including molluscs, crustaceans, insects, fish, and amphibians. Semiterrestrial marine animals such as crabs and mudskippers have gill chamber ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
