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Dikelocephalus
''Dikelocephalus'' is a genus of very large trilobites of up to long, that lived during the last 3 million years of the Cambrian ( Sunwaptan). Their fossils are commonly found as disarticulated sclerites, in the upper Mississippi Valley (northeastern Iowa, southeastern Wisconsin, central to western Wisconsin) and in Canada (Alberta). The exoskeleton is rounded anteriorly, with the thorax and sides of the tailshield (or pygidium) slightly tapering to about ⅔× of the width across the base of the spines at the back of the headshield (or cephalon). At the side corners of the pygidium there may be triangular or hooked spines, pointing backwards, while between the spines the posterior margin is at a 30-75° angle with the lateral margin, gently convex or nearly straight. If pygidial spines are lacking, the margin is gradually rounded. The thorax has 12 segments. Distribution The oldest known specimens of ''Dikelocephalus'' have been found in the upper part of the Tunnel City Gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dikelocephalidae
Dikelocephalidae is a family of trilobites, that lived during the Upper Cambrian. Relatively large eyes close to the 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 ..., is a shared characteristic. The following genera have been assigned to this family: *'' Berkeia'' *'' Blandicephalus'' *'' Briscoia'' *'' Camaraspoides'' *'' Dikelocephalus'' *'' Elkia'' *'' Goumenzia'' *'' Hoytaspis'' *'' Iranella'' *'' Kasachstanaspis'' *'' Monocheilus'' *'' Olimus'' *'' Osceolia'' *'' Parabriscoia'' *'' Patalolaspis'' *'' Princetonella'' *'' Pterocephalops'' *'' Randicephalus'' *'' Stigmacephalus'' *'' Taebaeksaukia'' *'' Walcottaspis'' References Dikelokephaloidea Trilobite families Cambrian first appearances Cambrian extinctions {{asaphida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saukiella
''Saukiella'' is a genus of trilobites of the Saukiidae family. These fast-moving low-level epifaunal deposit feeders lived in the Cambrian and Ordovician periods, from 498.5 to 478.6 Ma. Species * ''Saukiella baikadamica'' Ergaliev 1980 * ''Saukiella diversa'' Qiu 1984 * ''Saukiella pepinensis'' (Owen, 1852) (syn. Dikelocephalus pepinensis) Distribution Fossils of species within this genus have been found in the Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start ... sediments of Russia and in the Cambrian sediments of Canada, China, Kazakhstan and United States. References Saukiidae Asaphida genera Cambrian first appearances Ordovician extinctions Trilobites of Europe Trilobites of North America Paleozoic life of Alberta {{Asaphida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crepicephalus
''Crepicephalus'' is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived from 501 to 490 million years ago during the Dresbachian faunal stage of the late Cambrian Period 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 .... Reassigned species Some species, previously described as ''Crepicephalus'' have since been moved to other genera. * ''C. angusta'' = '' Kochaspis angusta'' * ''C. convexus'' = '' Crepicephalina convexa'' * ''C. liliana'' = '' Kochaspis liliana'' * ''C. nitidus'' = '' Dunderbergia nitida'' * ''C. quadrans'' = '' Ehmaniella quadrans'' * ''C. unca'' = '' Uncaspis unca'' References Ptychopariida genera Cambrian trilobites Extinct animals of North America Paleozoic life of Newfoundland and Labrador Paleozoic ... [...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] |
Ontogeny
Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the study of the entirety of an organism's lifespan. Ontogeny is the developmental history of an organism within its own lifetime, as distinct from phylogeny, which refers to the evolutionary history of a species. Another way to think of ontogeny is that it is the process of an organism going through all of the developmental stages over its lifetime. The developmental history includes all the developmental events that occur during the existence of an organism, beginning with the changes in the egg at the time of fertilization and events from the time of birth or hatching and afterward (i.e., growth, remolding of body shape, development of secondary sexual characteristics, etc.). While developmental (i.e., ontogenetic) processes can influence sub ... [...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 Common periwinkle, periwinkle). Furthermore, every so often, previously published volumes of the ''Treatise'' are revised. Evolution of the proje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
