Аспиделла
- Aspidella также омонимом грибного рода Saproamanita является
| Аспиделла | |
|---|---|
| |
| Люди Aspidella на плане постельного белья в формировании Fermeuse , Newfoundland | |
Научная классификация 
| |
| Домен: | Эукариота |
| Королевство: | Животное (?) |
| Род: | † aspidella Биллингс , 1872 |
| Разновидность: | † A. Terranovica
|
| Биномиальное название | |
| † Aspidella terranovica Биллингс, 1872
| |
| Синонимы | |
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Возможно многочисленные, см. Текст. | |
Aspidella -это эдиакарановый в форме окаменелость неопределенной сродства. Это известно от единственного вида A. terranovica . [ 1 ]
Морфология
[ редактировать ]Aspidella состоит из окаменелостей в форме дисков, с концентрическими кольцами и/или центростременными лучами. Диаметр круглой аспиделлы варьируется от 1 до 180 мм. [ 1 ] Большинство людей составляют от 4 до 10 мм, но меньшие люди, вероятно, распадались бы, прежде чем они смогут оформлять. Другие аспиделла принимают форму эллипсов , длиной 3–8 см и шириной 1–4 см. У большинства есть центральный прыщей. Обод всех образцов состоит из лучами с руками и/или концентрическими кольцами.
Экология
[ редактировать ]
Редкость крупных людей, вероятно, указывает на то, что Aspidella были R-стратегистами , производящие многочисленные потомство, большинство из которых умерли молодыми. Он наиболее распространен в глубоководных отложениях, но является составляющей большинства эдиакарских ископаемых сообщений, в том числе осажденных над базой штормовой волны . [ 2 ] Организмы могут достигать плотности более 3000 на квадратный метр. [ 2 ]
Аффинность
[ редактировать ]Just like Ediacaria (see also below), Aspidella has initially been considered a scyphozoan jellyfish. This initial designation has been refuted; some specimens have been shown to be the holdfast of some organism, the main body of which extended into the open water but broke off before fossilization (a few specimens bearing stubs of stalks opposed to the central pimple support this);[3][4] whereas others represent microbial colonies.[5]
Some individuals are associated with movement trails resembling those produced by modern sea anemones (Cnidaria).[6]
Taphonomy
[edit]The upper and lower surfaces of the fossils have a distinct elemental composition that resembles that of fossilized biofilms.[2] The sediment within the fossils also has a distinct composition, being enriched in certain elements with respect to the rock matrix. Since it is difficult to account for such a distribution of elements by post-mortem diagenetic processes, it would appear that the elements (and thus the sediment) were incorporated into the organism whilst it was alive.[2]
History of research
[edit]Aspidella terranovica was first discovered in 1868 by Scottish geologist Alexander Murray.[7] In 1872, Elkanah Billings described Aspidella terranovica fossils from Duckworth Street, St. John's, Newfoundland (47°34′01.3″N 52°42′18.3″W / 47.567028°N 52.705083°W).[8] They are preserved in a Neoproterozoic outcrop of black shale. Billings was the head paleontologist with the Geological Survey of Canada at the time. Even so, his findings were questioned by Charles Doolittle Walcott, who quoted opinion that the shapes in the rocks were concretions formed inorganically.[9] Other explanations offered at the time were that the circles were gas escape bubbles, or fakes planted by God to lure those with little faith into error[citation needed]. They were the first Ediacaran (Vendian) fossils described by a scientist.
For decades, Aspidella and its partner fossils were not considered to be Precambrian life forms. This lasted until the work of Reg Sprigg, who discovered the Ediacara Hills fossils.[10] Fossils were found in many other parts of the world in rocks of about the same age and became accepted as genuine remains of life forms.
Systematics and taxonomy
[edit]
Aspidella is derived from the Latin diminutive of Ancient Greek aspis (Ασπις, a round shield), and terranovica is Latin for "from the new land" (i.e. Newfoundland).
Different morphological forms have been called Ediacaria or Spriggia. However, the differences between the small elliptical "typical" Aspidella, the flat, ringed Spriggia wadea and the large, pimpled, and rayed Ediacaria seem to be due to different taphonomic conditions. For example, Spriggia and Ediacaria appear to be remains of the same animals, only that the former was fossilized in more compact, fine-grained clay, whereas the latter is known from rocks that originally were predominantly sandy sediment.[citation needed]
Numerous other taxa may also be junior synonyms of Aspidella:
- Beltanella
- Cyclomedusa
- Eoporpita
- Glaessneria
- Irridinitus
- Jampolium
- Madigania
- Medusinites
- Paliella
- Paramedusium
- Planomedusites
- Ediacaria
- Tateana
- Tirasiana
- Vendella
Due to its nondescript nature, Aspidella might be considered a form taxon, an artificial assemblage of similar-looking and similar-living organisms without a phylogenetic relationship. In this case, some presumed synonyms (such as Ediacaria or Cyclomedusa) would remain valid. The type specimens were of the ellipsoid type (they are lost, but a cast remains). Thus, if Aspidella in the loose sense turns out to be an assemblage of more or less related taxa, the genus name would apply only to the smallish ellipsoid specimens. Regardless of its ultimate classification, because it has been classified as either an animal, or a plant (alga), or a fungus (lichen), the name Aspidella is covered by both Codes of Nomenclature, and this prevents adoption of a later homonym "Aspidella" (Gilbert 1940) for a group of extant mushrooms, now renamed Saproamanita.[11]
Occurrence
[edit]Other locations where Aspidella specimens are reported include the Bonavista Peninsula and Mistaken Point in Newfoundland, the Twitya Formation in British Columbia, and central North Carolina.[12]
Aspidella fossils are found from 610 to 555 million years ago, with putative representatives dating to 770 million years ago.[13]
More recently, Aspidella fossils have been found in the mid-Tonian-aged Heavitree Formation, Amadeus Basin, Central Australia, dated to ~ 850 million years ago.[14]
See also
[edit]References
[edit]- ^ Jump up to: a b Peterson. P. 131
- ^ Jump up to: a b c d Laflamme, M.; Schiffbauer, J. D.; Narbonne, G. M.; Briggs, D. E. G. (2010). "Microbial biofilms and the preservation of the Ediacara biota". Lethaia. 44 (2): 203–213. doi:10.1111/j.1502-3931.2010.00235.x.
- ^ Narbonne, G. M. (2005). "THE EDIACARA BIOTA: Neoproterozoic Origin of Animals and Their Ecosystems". Annual Review of Earth and Planetary Sciences. 33: 421–442. Bibcode:2005AREPS..33..421N. doi:10.1146/annurev.earth.33.092203.122519.
- ^ MacGabhann, B. A. (2007). "Discoidal fossils of the Ediacaran biota: a review of current understanding". Geological Society, London, Special Publications. 286 (1): 297–313. Bibcode:2007GSLSP.286..297M. doi:10.1144/SP286.21. S2CID 129521521.
- ^ GRAZHDANKIN, D.; GERDES, G. (2007). "Ediacaran microbial colonies". Lethaia. 40 (3): 201–210. doi:10.1111/j.1502-3931.2007.00025.x. Archived from the original on 2013-01-05.
- ^ Evidence for Cnidaria-like behavior in ca. 560 Ma Ediacaran Aspidella Article in Geology 41:895-898 · February 2013
- ^ See:
- Murray, A. (1869). Report upon the Geological Survey of Newfoundland for 1868. St. John's, Newfoundland, Canada: Robert Winton. ; see p. 11.
- Murray, Alexander; Howley, James P. (1881). Geological Survey of Newfoundland. London, England: Edward Stanford. pp. 286, 297.
- ^ Billings, E. (1872). "On some fossils from the primordial rocks of Newfoundland". The Canadian Naturalist. 2nd series. 6 (4): 465–479. ; see p. 478.
- ^ Walcott, Charles D. (6 April 1899). "Pre-Cambrian fossiliferous formations". Bulletin of the Geological Society of America. 10 (1): 199–244. Bibcode:1899GSAB...10..199W. doi:10.1130/GSAB-10-199. hdl:2027/hvd.32044107306292. On p. 231, Walcott quotes "Mr. G.F. Matthew, of Saint John, New Brunswick": "I have seen Aspidella terranovica in the museum at Ottawa and doubt its organic origin. It seems to me a slickensided mud concretion striated by pressure."
- ^ Sprigg, Reg. C. (1947). "Early Cambrian (?) jellyfishes from the Flinders Ranges, South Australia". Transactions of the Royal Society of South Australia. 71 (2): 212–224.
- ^ Redhead SA, Vizzini A, Drehmel DC, Contu M (2016). « Sapromanita , новое название для Lepidella E.-J. Gilbert и Aspidella E.-J. Gilbert (Aniteae, Amanitaceae) » IMA гриб 7 (1): 119–1 Doi : 10.5598/ imafungus.2016.07.01.0 PMC 4941681 . PMID 27433443
- ^ Хиббард, JP; Поллок, JC; Бреннан, М.; Самсон, SD; Secor, D. (2009). «Значение новых эдикарановых окаменелостей и u -PB циркона возраста от группы Albemarle, Каролина Террейн из Северной Каролины». Журнал геологии . 117 (5): 487–498. Bibcode : 2009jg .... 117..487h . doi : 10.1086/600863 . S2CID 129184707 .
- ^ Mert, JG; Гибшер, как; Левашова, Нью -Йорк; Грайс, WC; Каменов, GD; Rybanin, A. (2010). «Оквалификация и ~ 770 мА эдиакара (?) Окаменелости из меньшего микроконтинента Каратау, Казахстан» Gondwana Research 19 (4): 867–8 Bibcode : 2011gondr..19..867m Doi : 10.1016/ j.2010.11.0
- ^ Пламмер, PS; Гортер, JD (2023). «Aspidella и Water Escape структуры из CA 850 млн. Лет (тонианская) формация тяжелой обработки, бассейн Амадея, Центральная Австралия» . Австралийский журнал наук о Земле . doi : 10.1080/08120099.2023.2290248 .
- Гелинг, Джеймс Г.; Нарбонн, Гай М.; Андерсон, Майкл М. (2000). «Первая названная эдиакаранская ископаемость,« Aspidella terranovica » . Палеонтология . 43 (3): 427–456. doi : 10.1111/j.0031-0239.2000.00134.x .
- Петерсон, Кевин Дж.; Вагонер, Бен; Hagadorn, James W. (2003). "Грибковой аналог для ископаемых в Ньюфаундленде Эдиакаран?" (PDF) . Интегративная и сравнительная биология . 43 (1): 127–136. doi : 10.1093/icb/43.1.127 . PMID 21680417 .
Внешние ссылки
[ редактировать ]- Бойс, WD; К. Рейнольдс (2008). «Ediacaran Fossil Aspidella Terranovica Billings, 1872 от Test Centre Center Center Convention Center Pit Cjae-33» (PDF) . С. 55–61 . Получено 17 декабря 2011 года .
- Хиббард, JP; JC Pollock; М. Бреннан; SD Samson; D. Secor (2009). «Значение новых эдикарановых окаменелостей и возраста циркона U-PB из группы Albemarle, Каролина Терран из Северной Каролины». Журнал геологии . 117 (5): 487–498. Bibcode : 2009jg .... 117..487h . doi : 10.1086/600863 . S2CID 129184707 .