Vendiamorpha
Encyclopedia
Vendiamorpha is a class
of extinct animals within the Ediacaran phylum
Proarticulata
.
The typical vendiamorph had an oval-shaped or round-shaped body divided completely into segmented isomers
, that are arranged alternately in two rows with reference to the longitudinal axis of body. This phenomenon is described as the symmetry of gliding reflection. Transverse elements decrease in size from one end to other and it inclined in the same direction. The larger isomers cover the smaller ones externally and the first isomer is much larger than the rest. Typically, the first few, or largest isomers are fused together to form a headshield-like structure, leading some researchers to originally consider them ancestral or related to arthropod
s, though, overwhelming evidence of them being proarticulatans have since lead researchers to discard this hypothesized relationship.
Some vendiamorphs, e.g, Vendia and Paravendia, supposedly demonstrate a digestive-distributive system consisting of a simple axial tube and lateral appendages, with one lateral appendage corresponding to one isomer.
Class Vendiamorpha currently includes only one Family
Vendiidae (originally referred to as Vendomiidae as the type genus
Vendomia, before V. menneri was redescribed as a member of Dickinsonia
) that consist of species Vendia sokolovi, V. rachiata, Paravendia janae and Karakhtia nessovi from Ediacaran
(Vendian) rocks of the Arkhangelsk Region, Russia
, and Podolimirus mirus from the Podolia
, Ukraine
. Pseudovendia, of the Charnwood Biota, may or may not be a vendiamorph, or it may be a frond-like organism.
Class (biology)
In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
of extinct animals within the Ediacaran phylum
Phylum
In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....
Proarticulata
Proarticulata
Proarticulata is a proposed extinct phylum of very early bilateral animals known from fossils found in the Ediacaran fauna. Mikhail A. Fedonkin describes animals in Proarticulata as having a "shield-like" shape, an unmineralized, thin, flexible carapace and a thick, segmented body...
.
The typical vendiamorph had an oval-shaped or round-shaped body divided completely into segmented isomers
Isomer (Proarticulata)
Isomer is an element of transverse body articulation of the bilateral fossil animals of the Phylum Proarticulata from the Ediacaran period. This term has been proposed by Andrey Yu...
, that are arranged alternately in two rows with reference to the longitudinal axis of body. This phenomenon is described as the symmetry of gliding reflection. Transverse elements decrease in size from one end to other and it inclined in the same direction. The larger isomers cover the smaller ones externally and the first isomer is much larger than the rest. Typically, the first few, or largest isomers are fused together to form a headshield-like structure, leading some researchers to originally consider them ancestral or related to arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s, though, overwhelming evidence of them being proarticulatans have since lead researchers to discard this hypothesized relationship.
Some vendiamorphs, e.g, Vendia and Paravendia, supposedly demonstrate a digestive-distributive system consisting of a simple axial tube and lateral appendages, with one lateral appendage corresponding to one isomer.
Class Vendiamorpha currently includes only one Family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Vendiidae (originally referred to as Vendomiidae as the type genus
Type genus
In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...
Vendomia, before V. menneri was redescribed as a member of Dickinsonia
Dickinsonia
Dickinsonia is an iconic fossil of the Ediacaran biota. It resembles a bilaterally symmetrical ribbed oval. Its affinities are presently unknown; most interpretations consider it to be an animal, although others suggest it may be fungal, or a member of an "extinct kingdom".-Species variety:A...
) that consist of species Vendia sokolovi, V. rachiata, Paravendia janae and Karakhtia nessovi from Ediacaran
Ediacaran
The Ediacaran Period , named after the Ediacara Hills of South Australia, is the last geological period of the Neoproterozoic Era and of the Proterozoic Eon, immediately preceding the Cambrian Period, the first period of the Paleozoic Era and of the Phanerozoic Eon...
(Vendian) rocks of the Arkhangelsk Region, Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, and Podolimirus mirus from the Podolia
Podolia
The region of Podolia is an historical region in the west-central and south-west portions of present-day Ukraine, corresponding to Khmelnytskyi Oblast and Vinnytsia Oblast. Northern Transnistria, in Moldova, is also a part of Podolia...
, Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...
. Pseudovendia, of the Charnwood Biota, may or may not be a vendiamorph, or it may be a frond-like organism.
External links
- "Database of Ediacaran Biota" Advent of Complex Life