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Phytoclast
Phytoclasts are microscopic plant fragments present in the fossil record, usually found in palynological preparations and acid macerations, and include banded tubes and various nematophytes. References Fossil record of plants Prehistoric plants {{paleobotany-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Banded Tube
Banded tubes are a type of phytoclast Phytoclasts are microscopic plant fragments present in the fossil record, usually found in palynological preparations and acid macerations, and include banded tubes and various nematophytes. References Fossil record of plants Prehistoric ... consisting of micrometre-scale tubes with a banded internal ornamentation, and known from terrestrial/freshwater settings from the Early Silurian onwards. The bands on the walls were an early improvisation to aid the easy flow of water, and served as tracheids, although they are not equivalent in their construction. Banded tubes were lignified, giving them a more rigid structure than hydroids, allowing them to cope with higher levels of water pressure. Banded tubes have a markedly different ultrastructure from plant tracheids, and display a wide variety of wall structures, which implies that they were produced by a variety of different organisms, or perhaps were widely variable within a sing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Banded Tubes
Banded tubes are a type of phytoclast Phytoclasts are microscopic plant fragments present in the fossil record, usually found in palynological preparations and acid macerations, and include banded tubes and various nematophytes. References Fossil record of plants Prehistoric ... consisting of micrometre-scale tubes with a banded internal ornamentation, and known from terrestrial/freshwater settings from the Early Silurian onwards. The bands on the walls were an early improvisation to aid the easy flow of water, and served as tracheids, although they are not equivalent in their construction. Banded tubes were lignified, giving them a more rigid structure than hydroids, allowing them to cope with higher levels of water pressure. Banded tubes have a markedly different ultrastructure from plant tracheids, and display a wide variety of wall structures, which implies that they were produced by a variety of different organisms, or perhaps were widely variable within a sing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nematophyte
The Nematophyta or nematophytes are a paraphyletic group of land organisms, probably including some plants as well as algae known only from the fossil record, from the Silurian period until the early Devonian Rhynie chert. The type genus ''Nematothallus'', which typifies the group, was first described by Lang in 1937, who envisioned it being a thallose plant with tubular features and sporophytes, covered by a cuticle which preserved impressions of the underlying cells. He had found abundant disaggregated remains of all three features, none of which were connected to another, leaving his reconstruction of the phytodebris as parts of a single organism highly conjectural. No reproductive or vegetative structures common to the land plants are known, and certain members of the nematophyte plexus (including ''Nemataplexus ''Nematoplexus rhyniensis'' is a fossil known from the Rhynie chert assigned to the nematophytes. It comprises a loose mass of coily aseptate tubes. Tubes whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmochlaina
''Cosmochlaina'' (from Greek: kosmos=ornament; xlaina=wrapper/cloak) is a form genus of nematophyte – an early (Silurian – Devonian) plant known only from fossil cuticles, often found in association with tubular structures. The form genus was put forwards by Dianne Edwards, and is diagnosed by inwards-pointing flanges and randomly oriented pseudo-cellular units. Projections on the outer surface are always present, and sometimes also appear on the inner surface; however, the surface of the cuticle itself is always smooth. The holes in the cuticle are often covered by round flaps, loosely attached along a side. Where ''Nematothallus'' was sometimes used to relate only to tube-like structures, ''Cosmochlaina'' was used in reference to the cuticle fragments. Material discovered later revealed its internal anatomy, which comprises a lichen-like mat of 'hyphae'. It has been suggested that the pores of'' Cosmochlaina ''represent broken-off rhizoids, on the basis that rotting and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palynological
Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposits including sediments of any age. The condition and identification of those particles, organic and inorganic, give the palynologist clues to the life, environment, and energetic conditions that produced them. The term is commonly used to refer to a subset of the discipline, which is defined as "the study of microscopic objects of macromolecular organic composition (i.e., compounds of carbon, hydrogen, nitrogen and oxygen), not capable of dissolution in hydrochloric or hydrofluoric acids". It is the science that studies contemporary and fossil palynomorphs (paleopalynology), including pollen, spores, orbicules, dinocysts, acritarchs, chitinozoans and scolecodonts, together with particulate organic matter (POM) and kerogen found in sedimenta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid Macerations
Fossil preparation is the act of preparing fossil specimens for use in paleontological research or for exhibition, and involves removing the surrounding rocky matrix and cleaning the fossil. Techniques Acid maceration Acid maceration is a technique to extract organic microfossils from a surrounding rock matrix using acid. Hydrochloric acid or acetic acid may be used to extract phosphatic fossils, such as the small shelly fossils, from a carbonate matrix. Hydrofluoric acid is also used in acid macerations to extract organic fossils from silicate rocks. Fossiliferous rock may be immersed directly into the acid, or a cellulose nitrate film may be applied ( dissolved in amyl acetate), which adheres to the organic component and allows the rock to be dissolved around it. Film pull The film pull technique is a means of recovering carbonaceous compression fossils for study under transmitted light microscopy. An acid is applied to the surface of the rock to etch away the matrix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Record Of Plants
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
