| Redkinia Temporal range: | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | incertae sedis |
| Genus: | † Redkinia Sokolov,1977 |
Redkinia is a genus of rod-like Ediacaran fossil fringed with large and small projections [1] which has been putatively compared with the mandibles of an Arthropod [2] and the mouthparts of Wiwaxia and Odontogriphus [3] . If it were to have been a jaw, it would have been used for filter-feeding rather than crushing. [4]
The Cambrian Period 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 485.4 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 lagerstätte 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 biology surpasses that of some later periods.
The Ediacaran Period is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and the beginning of the Phanerozoic Eon. It is named after the Ediacara Hills of South Australia.
The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago.
The cloudinids, an early metazoan family containing the genera Acuticocloudina, Cloudina and Conotubus, lived in the late Ediacaran period about 550 million years ago. and became extinct at the base of the Cambrian. They formed millimetre-scale conical fossils consisting of calcareous cones nested within one another; the appearance of the organism itself remains unknown. The name Cloudina honors the 20th-century geologist and paleontologist Preston Cloud.
An exoskeleton is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeletons within animals include the arthropod exoskeleton shared by chelicerates, myriapods, crustaceans, and insects, as well as the shell of certain sponges and the mollusc shell shared by snails, clams, tusk shells, chitons and nautilus. Some animals, such as the turtle, have both an endoskeleton and an exoskeleton.
Dickinsonia is an extinct genus of basal animal that lived during the late Ediacaran period in what is now Australia, China, India, Russia and Ukraine. The individual Dickinsonia typically resembles a bilaterally symmetrical ribbed oval. Its affinities are presently unknown; its mode of growth is consistent with a stem-group bilaterian affinity, though some have suggested that it belongs to the fungi, or even an "extinct kingdom". The discovery of cholesterol molecules in fossils of Dickinsonia lends support to the idea that Dickinsonia was an animal.
Charnia is a genus of frond-like lifeforms belonging to the Ediacaran biota with segmented, leaf-like ridges branching alternately to the right and left from a zig-zag medial suture. The genus Charnia was named after Charnwood Forest in Leicestershire, England, where the first fossilised specimen was found. Charnia is significant because it was the first Precambrian fossil to be recognized as such.
A trace fossil, also known as an ichnofossil, is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms' bodies, usually altered by later chemical activity or mineralization. The study of such trace fossils is ichnology and is the work of ichnologists.
A microfossil is a fossil that is generally between 0.001 mm and 1 mm in size, the visual study of which requires the use of light or electron microscopy. A fossil which can be studied with the naked eye or low-powered magnification, such as a hand lens, is referred to as a macrofossil.
Spriggina is a genus of early bilaterian animals whose relationship to living animals is unclear. Fossils of Spriggina are known from the late Ediacaran period in what is now South Australia. Spriggina floundersi is the official fossil emblem of South Australia. It has been found nowhere else. The organism reached about 3–5 centimetres (1.2–2.0 in) in length and may have been predatory. Its bottom was covered with two rows of tough interlocking plates, while one row covered its top; its front few segments fused to form a "head."
Ediacaria is a fossil genus dating to the Ediacaran Period of the Neoproterozoic Era. Unlike most Ediacaran biota, which disappeared almost entirely from the fossil record at the end of the Period, Ediacaria fossils have been found dating from the Baikalian age of the Upper Riphean to 501 million years ago, well into the Cambrian Period. Ediacaria consists of concentric rough circles, radial lines between the circles and a central dome, with a diameter from 1 to 70 cm.
The Ediacaranbiota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period. These were composed of enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms.
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage in which their body consists of a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 micrometres (0.00033 in) to 33.6 metres (110 ft). They have complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology.
The "Cambrian substrate revolution" or "Agronomic revolution", evidenced in trace fossils, is the diversification of animal burrowing during the early Cambrian period.
The small shelly fauna, small shelly fossils (SSF), or early skeletal fossils (ESF) are mineralized fossils, many only a few millimetres long, with a nearly continuous record from the latest stages of the Ediacaran to the end of the Early Cambrian Period. They are very diverse, and there is no formal definition of "small shelly fauna" or "small shelly fossils". Almost all are from earlier rocks than more familiar fossils such as trilobites. Since most SSFs were preserved by being covered quickly with phosphate and this method of preservation is mainly limited to the late Ediacaran and early Cambrian periods, the animals that made them may actually have arisen earlier and persisted after this time span.
The Cambrian explosion, Cambrian radiation,Cambrian diversification, or the Biological Big Bang refers to an interval of time approximately 538.8 million years ago in the Cambrian Period when practically all major animal phyla started appearing in the fossil record. It lasted for about 13 – 25 million years and resulted in the divergence of most modern metazoan phyla. The event was accompanied by major diversification in other groups of organisms as well.
Ediacaran type preservation relates to the dominant preservational mode in the Ediacaran period, where Ediacaran organisms were preserved as casts on the surface of microbial mats.
Gregory John Retallack is an Australian paleontologist, geologist, and author who specializes in the study of fossil soils (paleopedology). His research has examined the fossil record of soils though major events in Earth history, extending back some 4.6 billion years. Among his publications he has written two standard paleopedology textbooks, said N. Jones in Nature Geoscience "Retallack has literally written the book on ancient soils."
Megaevolution describes the most dramatic events in evolution. It is no longer suggested that the evolutionary processes involved are necessarily special, although in some cases they might be. Whereas macroevolution can apply to relatively modest changes that produced diversification of species and genera and are readily compared to microevolution, "megaevolution" is used for great changes. Megaevolution has been extensively debated because it has been seen as a possible objection to Charles Darwin's theory of gradual evolution by natural selection.
Namalia was first described in 1968 by G. J. B. Germs from an outcrop near Helmeringhausen, Namibia and Namalia dates back to the Ediacaran Period . Namalia has a conical structure and it is thought that it lived semi-buried in sediment along the seafloor.
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