Vendiamorpha
| Vendiamorpha | ||||||
|---|---|---|---|---|---|---|
P aravendia janae , Vendia Sokolovi and Vendia rachiata |
||||||
| Temporal occurrence | ||||||
| Ediacarium | ||||||
| 558 to 550 million years | ||||||
| Locations | ||||||
| Systematics | ||||||
|
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| Scientific name | ||||||
| Vendiamorpha | ||||||
| Fedonkin , 1985 | ||||||
| Familys | ||||||
The Vendiamorpha are a class of extinct animals of the Ediacariums that belong to the Proarticulata tribe (or to the clade Bilateriomorpha ).
etymology
The name Vendiamorpha is a word creation that is composed of the taxon name Vendia and the ancient Greek μορφή morphé meaning ' shape , form'. Vendia, in turn, is derived from the Vendium , a period of the Neoproterozoic , which in turn refers to the Slavic tribe of the Wends . Vendiamorpha thus means all forms with a Vendia- like shape.
First description and occurrence
The class Vendiamorpha was established in 1985 by Mikhail Alexandrowitsch Fedonkin . Their fossil finds are limited to the southeastern coastal area of the White Sea ( Arkhangelsk Oblast ).
description
Typical Vendiamorpha had a round or oval, relatively flat body, which was completely divided into so-called isomers . The isomers were arranged in two rows. However, they were not mirror-inverted, but offset from one another by half a width along the body axis by sliding reflections .
These transversal elements steadily decrease in size towards the end of the tail, at the same time they bend inwards towards the body axis. The first isomer is much larger than the others. Vendiamorpha is characterized by the intergrowth of the first two isomers to form a headshield-like structure. This feature prompted some researchers to move the Vendiamorpha closer to the arthropods . In the meantime, however, there is much to suggest that they are clearly related to the Proarticulata .
In some Vendiamorpha fossils, such as Vendia or Paravendia , the remains of a digestive system have apparently been preserved, which is made up of a simple axial tube with lateral processes for each individual isomer.
Taxonomy
The class of Vendiamorpha currently has only one family, the Vendiidae . The Vendiidae were previously called Vendomiidae after their type genus Vendomia , but Vendomia menneri was later described as belonging to Dickinsonia (= Dickinsonia menneri ). The taxon Karakhtia cannot be clearly assigned.
Family Vendiidae
The Vendiidae include the following taxa:
-
Vendia Keller , 1969
- Vendia sokolovi cellar , 1969
- Vendia rachiata Ivantsov , 2004
-
Paravendia Ivantsov , 2004
- Paravendia janae
Family of uncertain assignment
-
Karakhtia Ivantsov , 2004
- Karakhtia nessovi
The Pseudovendia fossil is somewhat similar to Vendia sokolovi . It was originally interpreted as an arthropod, then classified as belonging to the Proarticulata and even viewed as a frondomorphic organism. The poorly preserved holotype is now mostly interpreted as a pseudofossil.
See also
Individual evidence
- ^ A b M. A. Fedonkin: Systematic Description of Vendian Metazoa . Ed .: Sokolov, BS and Iwanowski, AB, "Vendian System: Historical-Geological and Paleontological Foundation, Vol. 1: Paleontology". Nauka, Moscow 1985, p. 70-106 .
- ^ Ivantsov, AY: Vendia and Other Precambrian "Arthropods" . In: Paleontological Journal . tape 35 (4) , 2001, p. 335-343 .
- ^ VV Menner: The Other Problematical Organic Remains (in Russian) . In: Stratigraphy of the USSR: Upper Precambrian . Gos. Nauchno-Tekh. Izd., Moscow 1963, p. 504-507 .
- ^ Ivantsov, AY: New Proarticulata from the Vendian of the Arkhangel'sk Region . In: Paleontological Journal . tape 38 (3) , 2004, p. 247-253 .
- ^ HE Boynton and TD Ford: Pseudovendia charnwoodensis - A new Precambrian arthropod from Charnwood Forest, Leicestershire . In: Mercian Geologist . tape 7 , 1979, pp. 175-177 .
- ^ HE Boynton: Charnian Fossils in the Outwoods . In: Mercian Geologist . tape 17 (3) , 2010, pp. 175-177 .
- ^ Liu, AG et al.: Effaced preservation in the Ediacara biota and its implications for the early macrofossil record . In: Palaeontology . tape 54 (3) , 2010, pp. 607-630 , doi : 10.1111 / j.1475-4983.2010.01024.x .