Charniodiscus
| Charniodiscus | ||||||||
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Cast of the type fossil Charniadiscus concentricus from Charnwood Forest in England |
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| Temporal occurrence | ||||||||
| Ediacarium | ||||||||
| 565 to 555 million years | ||||||||
| Locations | ||||||||
| Systematics | ||||||||
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| Scientific name | ||||||||
| Charniodiscus | ||||||||
| Ford , 1958 | ||||||||
| species | ||||||||
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Charniodiscus is a fossil from the Ediacarium , which iscountedamong the Rangeomorpha .
etymology
The compound word Charniodiscus is derived from Charn - the first syllable of Charnwood - and the ancient Greek δίσκος (diskos) meaning "plate", "disc" or "throwing disc".
Discovery and type locality
Charniodiscus was discovered in the Charnian Supergroup in Charnwood Forest near Leicester . The first scientific description of the fossil was in 1958 by Trevor D. Ford . Ford named the fossil type Charniodiscus concentricus , referring to the adhesive disc, which is marked by two concentric circles. A later discovered "frond" (frond) belonged to the closely related taxon Charnia masoni , which differs in the branching pattern of the frond.
distribution
In addition to the type locality in the Charnwood Forest, Charniodiscus has so far been found at the following sites:
- Mistaken Point , Avalon Peninsula , Newfoundland. The fossils come from the 575 to 565 million year old BP Mistaken Point Formation , which is part of the Coronation Group .
- Ediacaran Hills in South Australia
- White Sea coast in Russia
- Wernecke Mountains in northwest Canada ( Yukon )
description
Charniodiscus arboreus
The morphologically similar sea feather Virgularia
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The Fossil Charniodiscus , which belongs to the Ediacara biota (575 to 543 million years BP), was probably a filter feeder stuck on the sea floor. The organism consisted of an anchoring disc, an upright stem and a branched, leaf-shaped section, which, in this and the related forms, is referred to as "frond", translated as "frond", because of the similarity to fern fronds . The anchor plate was curved upwards and the stem was flexible. The pointed frond was made up of individual segments. Two forms of growth can be distinguished: a short-stemmed one with a flat frond and a long-stemmed one with a smaller frond that only started 50 centimeters above the anchoring disc.
Biological affinity
Charniodiscus is superficially similar to sea feathers (Pennatulacea, Cnidaria ), but is very probably not a corolla group animal, as the different growth mode of new frond elements suggests (in Pennatulacea the growth occurs from below, whereas in Charniodiscus the growth took place at the tip of the frond ). Morphological similarities also exist with Thaumnaptilon walcotti from the Burgess fauna from the middle Cambrian , in which zooids are likely to have been preserved. As alternative affinities, prokaryotic colony formers, grown ancestors of the comb jellyfish (Ctenophora), such as Stromatoveris from the Chengjiang fauna community in China , fruiting bodies of marine mushrooms or Vendobionta sensu Seilacher are mentioned. Despite the uncertainties in the phylogenetic classification, based on the structuring of the ecocoenoses of the Mistaken Point biota, it can be assumed that Charniodiscus was a suspension filter that drew food from the surrounding water column with its fronds protruding above the sea floor.
Habitat
Sedimentological studies in the Mistaken Point Formation in Newfoundland show that Charniodiscus was located in the deep water area below the storm wave base.
Taxonomy
The distinction in single taxa is based on the number of individual segments, if a distal stem (spine) is present or not, and the morphometric sizes to width ratio ( English shape ratio ). The following taxa exist from Charniodiscus :
With more than 20 primary branches:
- Charniodiscus arboreus (Australia)
- Charniodiscus concentricus
- Charniodiscus longus
- Charniodiscus oppositus
With fewer than 15 primary branches:
- Charniodiscus procerus (Newfoundland)
- Charniodiscus spinosus (Newfoundland)
Age
Charniodiscus occurs in formations between 565 and 555 million years BP .
literature
- Laflamme, M., Narbonne, GM and Anderson, MM: Morphometric analysis of the Ediacaran frond Charniodiscus from the Mistaken Point Formation, Newfoundland . In: Journal of Paleontology . tape 78 (5) , 2004, pp. 827-837 .
Individual evidence
- ↑ Boynton, HE and Ford, TD: Ediacaran Fossils from the Precambrian (Charnian Supergroup) of Charnwood Forest, Leceistershire, England . In: Mercian-Geologist . tape 13 , 1995, pp. 165-182 .
- ^ Jenkins, RJF: Aspects of the geological setting and palaeobiology of the Ediacara assemblage . Ed .: Davies, M. et al., Natural History of the Flinders Ranges. tape 7 . Royal Society of South Australia, Richmond, South Australia 1996.
- ↑ Fedonkin, MA: Skeleton-free fauna of the Vendian: morphological analysis . Ed .: Sokolov, BSE and Ivanovskiy, AB Nauka, Moscow 1985.
- ↑ Narbonne, GM and Hofmann, HJ: Ediacaran biota of the Wernecke Mountains, Yukon, Canada . In: Palaeontology . tape 30 , p. 647-676 .
- ^ A b Clapham, ME et al: Paleo-ecology of the oldest-known animal communities: Ediacaran assemblages at Mistaken Point, Newfoundland . In: Paleobiology . tape 29 , 2003, p. 527-544 .
- ↑ Antcliffe, JB and Brasier, MD: Charnia and sea pens are poles apart . In: Journal of the Geological Society, London . tape 164 , 2007, p. 49-51 .
- ^ Conway Morris, S .: Ediacaran-like fossils in Cambrian Burgess Shale-type faunas of North America . In: Palaeontology . tape 36 , 1993, pp. 593-635 .
- ↑ Steiner, M. and Reitner, J .: Evidence of organic structures in Ediacara-type fossils and associated microbial mats . In: Geology . tape 29 , 2001, p. 1119-1122 .
- ↑ Dzik, J .: Possible ctenophoran affinities of the Precambrian seapen Rangea . In: Journal of Morphology . tape 252 , 2002, pp. 315-334 .
- ↑ Shu, D.-G. inter alia: Lower Cambrian vendobionts from China and early diploblast evolution . In: Science . tape 312 , 2006, pp. 731-734 .
- ^ Peterson, KJB et al.: A fungal analog for Newfoundland Ediacaran fossils? In: Integrated and Comparative Biology . tape 43 , 2003, p. 127-136 .
- ↑ Buss, LW and Seilacher, A .: The Phylum Vendobionta: a sister group of the Eumetazoa? In: Paleobiology . tape 20 , 1994, p. 1-4 .
- ↑ Wood, DA et al .: Paleoenvironmental analysis of the late Neoproterozoic Mistaken Point and Trepassey formations, southeastern Newfoundland . In: Canadian Journal of Earth Sciences . tape 40 , 2003, p. 1375-1391 .