|
Rangeomorphs
The rangeomorphs are a form taxon of frondose Ediacaran fossils that are united by a similarity to ''Rangea''. Some researchers, such as Pflug and Narbonne, suggest that a natural taxon Rangeomorpha may include all similar-looking fossils. Rangeomorphs appear to have had an effective reproductive strategy, based on analysis of the distribution pattern of ''Fractofusus misrai'', which consisted of sending out a waterborne asexual propagule to a distant area, and then spreading rapidly from there, just as plants today spread by stolons or runners. Rangeomorphs are a key part of the Ediacaran biota, which survived about 30 million years, until the base of the Cambrian, which was . They were especially abundant in the early Ediacaran Mistaken Point assemblage found in Newfoundland. Body plan Rangeomorphs consist of branching "frond" elements, each a few centimetres long, each of which is composed of many smaller branching tubes held up by a semi-rigid organic skeleton. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frondose
Frondosity (from Latin ''frondōsus'' meaning 'leafy') is the property of an organism that normally flourishes with fronds or leaf-like structures. Many frondose organisms are thalloid and lack the organization of tissues into organs, with the exception of ferns. Frondosity is significant mainly for distinguishing particular types of macroscopic algae, and in paleobotany and paleontology, by analyzing features present in fossil biota. Frondose macroalgae are relevant to the ecology of many marine and coastal ecosystems. Large frondose algae play an important role in the creation and functioning of healthy ecosystems from kelp forests to similar habitats. Yet, in coral reefs, frondose seaweed can be recognized as harmful due to the link between excessive blooms and coastal eutrophication. Ediacaran biota The fossil record from the Ediacaran Period is sparse, as more easily fossilized hard-shelled animals had yet to evolve. Most fossils of the time are only faint impressi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trepassia
''Trepassia'' is a 579 million-year-old fossil of Ediacaran rangeomorph. It was first discovered by Guy M. Narbonne, a professor at Queen's University in Ontario, Canada and colleagues in 2009. Three years later, Martin D. Brasier added additional description to ''Trepassia.'' The generic name is taken from the French word, trépassés, which translates to "those that have departed forever" (or "corpses") and honors the Trepassey community in Newfoundland. It was originally described as ''Charnia wardi''; it was referred under this synonym in a 2016 paper. Morphology ''Trepassia'' is one of the oldest known rangeomorphs and spanned over one meter in length. Longest specimens of ''T. wardae'' reached .M. LAFLAMME, G. M. NARBONNE, C. GREENTREE & M. M. ANDERSON. 2016. Morphology and taphonomy of an Ediacaran frond: Charnia from the Avalon Peninsula of Newfoundland. Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario, Canada K7L 3N6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avalofractus
''Avalofractus abaculus'' is a frond-like rangeomorph fossil described from the Ediacaran of the Trepassey Formation, Spaniard's Bay, Newfoundland. Morphology ''Avalofractus'' displays a strongly fractal body shape, with four levels of nearly perfectly self-similar, pinnate, alternate branches. It was about 5 cm long on average, with a 1 cm-diameter holdfast at the base of the frond. The stem length is from 1/3 to 1/2 that of the whole frond. It is quite similar to ''Rangea'', even if with distinct morphological differences that justify the creation of a new genus (e.g. absence of subsidiary quilts, frond elements free to rotate independently instead of being attached to each other by a membrane). Distribution In contrast with other rangeomorphs, which have wide distributions, ''Avalofractus'' seems to have been an endemic species, being known only from the Spaniard's Bay deposits. Reproduction It has been suggested that ''Avalofractus'' could have been capable of ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stolon
In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external skeletons. In botany In botany, stolons are stems which grow at the soil surface or just below ground that form adventitious roots at the nodes, and new plants from the buds. Stolons are often called runners. Rhizomes, in contrast, are root-like stems that may either grow horizontally at the soil surface or in other orientations underground. Thus, not all horizontal stems are called stolons. Plants with stolons are called stoloniferous. A stolon is a plant propagation strategy and the complex of individuals formed by a mother plant and all its clones produced from stolons form a single genetic individual, a genet. Morphology Stolons may or may not have long internodes. The leaves along the stolon are usually very small, but in a few ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hapsidophyllas
''Hapsidophyllas'' is a rare Ediacaran rangeomorph fossil found at Mistaken Point, Newfoundland, Canada. It was first identified by Emily Bamforth and Guy Narbonne in 2009. Its name comes from the Greek words for “a network of leaves.” Because its characteristic flexible leaflet structure is dissimilar to other known rangeomorphs, Bamforth and Narbonne describe it as a new rangeomorph form, called hapsidophyllid. The only other known hapsidophyllid is the Ediacaran frond '' Frondophyllas grandis'', which shares the network-like configuration of leaflets seen in ''Hapsidophyllas''. Currently, the ''Hapsidophyllas flexibilis'' holotype resides in its type locality in the Mistaken Point Ecological Reserve, and a cast of the specimen is on display at the Royal Ontario Museum in Toronto, Canada. The ''Hapsidophyllas flexibilis'' holotype is 110 mm long and 4 mm wide. It is composed of multibranched leaflets radiating from a single elongate basal rod. The leaflets gradual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hylaecullulus
''Hylaecullulus fordi'' is a species of Ediacaran petalonamid from the Charnwood Forest of Leicestershire, England that serves as an important rangeomorph because of its multifoliate anatomy, known from its fossils. Its overall body plan is similar to that of a goblet, from which its name, ''Hylaecullulus'', derives. Etymology The name ''Hylaecullulus fordi'' derives from its occurrence within Charnwood Forest: , (which means 'from the woods' in Ancient Greek and , which means 'small goblet' in that language. The name of the type species, "fordi", was given to honour Trevor Ford, who made important contributions to the Ediacaran fauna. Discovery ''Hylaecullulus fordi'' was discovered in the hilly tract of Charnwood Forest in 2018 by a team led by C. G. Kenchington. This team found six well-preserved fossils, all of which had fossilised with the lateral view of the animal visible, from the top of the Bradgate Formation of the Maple Group. Although two specimens out of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paracharnia
''Paracharnia'' is a reassessed genus of a fossil reported by Ding and Chen (1981). It is the first Ediacaran metazoan fossilized remains found in China, taken from the Shibantan Member, Dengying Formation, Sinian System in the Eastern Yangtze Gorge, Hubei Province. It was initially classified as ''Charnia dengyingensis'', but Sun Weiguo in 1986, comparing this to findings from Charnwood in England and the Ediacara assemblage of South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ..., identified it as a new genera. ''Paracharnia'' is a pennatulid within the taxon of Rangeomorpha. It is closely associated with macroscopic algal remains of ''Vendotaenia'' and dense Cambrian shelly fossil deposits, suggesting its paleontological relevance. The original fossil extraction f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Culmofrons
''Beothukis mistakensis'' is a rare fossil frond-like member of the Rangeomorpha, described from the Ediacaran of Mistaken Point, Newfoundland. It had been identified since 1992, referred in papers as a "spatulate frond" or "flat recliner", but not formally described until 2009. The original fossils from which the genus has been described are still ''in situ'', but replicas are preserved at the Memorial University of Newfoundland and at the Oxford University Museum of Natural History. Claims of a stem have been contentious, and based largely on structures that have subsequently been determined to be erosional scours, and is so considered to be a recliner Morphology ''Beothukis'' appears as a frond composed of two asymmetrical rows of branches that depart from a central growth axis, 12.5–15.5 cm long and 4.5–6 cm wide. Secondary growth is present around the tip. Secondary order units cross the primary order axes as is common in the Charnida The alternations are irr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Form Taxon
Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of science is to move "form taxa" to biological taxa whose affinity is known. Form taxonomy is restricted to fossils that preserve too few characters for a conclusive taxonomic definition or assessment of their biological affinity, but whose study is made easier if a binomial name is available by which to identify them. The term "form classification" is preferred to "form taxonomy"; taxonomy suggests that the classification implies a biological affinity, whereas form classification is about giving a name to a group of morphologically-similar organisms that may not be related. A "parataxon" (not to be confused with parataxonomy), or "sciotaxon" (Gr. "shadow taxon"), is a classification based on incomplete data: for instance, the larval stage o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charnia
''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 (thus exhibiting glide reflection, or opposite isometry). 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. The living organism grew on the sea floor and is believed to have fed on nutrients in the water. Despite ''Charnia'' fern-like appearance, it is not a photosynthetic plant or alga because the nature of the fossilbeds where specimens have been found implies that it originally lived in deep water, well below the photic zone where photosynthesis can occur. Diversity Several ''Charnia'' species were described but only the type species ''C. masoni'' is considered valid. Some specimens of ''C. masoni'' were described as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ediacaran
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 Ediacaran Period's status as an official geological period was ratified in 2004 by the International Union of Geological Sciences (IUGS), making it the first new geological period declared in 120 years. Although the period takes its name from the Ediacara Hills where geologist Reg Sprigg first discovered fossils of the eponymous Ediacaran biota in 1946, the type section is located in the bed of the Enorama Creek within Brachina Gorge in the Flinders Ranges of South Australia, at . The Ediacaran marks the first appearance of widespread multicellular fauna following the end of Snowball Earth glaciation events, the so-called Ediacaran biota, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ediacaran Biota
The Ediacaran (; formerly Vendian) biota is a Taxonomy (biology), 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 sessility (zoology), sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The Ediacaran biota may have undergone evolutionary radiation in a proposed event called the Avalon explosion, . This was after the Earth had thawed from the Cryogenian period's Snowball Earth, extensive glaciation. This biota largely disappeared with the rapid increase in biodiversity known as the Cambrian explosion. Most of the currently existing body plans of animals first appeared in the fossil, fossil record of the Cambrian rather than the Ediacaran. For macroorganisms, the Cambrian biota appears to have almost completely replaced the organisms that dominate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
