Ovatoscutum
Encyclopedia
Ovatoscutum is one of many enigmatic organism known from Ediacaran deposites of the Flinders Ranges, Australia and the White Sea area, Russia. This genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 contains one species, Ovatoscutum concentricium.

This fossil have form of a rounded shield, sculptured with strong concentric corrugation/ribs, which weakens adjacent to a triangular neckline. A suture-like zone extends through the centre from the tip of the neckline towards the opposite margin. The ribs become wider towards the periphery.

Ovatoscutum was first described by Martin Glaessner
Martin Glaessner
Martin Fritz Glaessner AM was a geologist and palaeontologist. Born and educated in Austro-Hungarian Empire, he spent the majority of his life in working for oil companies in Russia, and studying the geology of the South Pacific in Australia...

 and Mary Wade in 1966 and with doubt has been interpreted as a chondrophoran pneumatophore. This idea was based on some similarity of Ovatoscutum with Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...

 Plectodiscus that was interpreted as velellid float (pneumatophore) and with modern chondrophoran pneumatophore Velella
Velella
Velella is a genus of free-floating hydrozoans that lives on the surface of the open ocean, worldwide, and is commonly known by the names by-the-wind sailor, purple sail, little sail, or simply Velella...

. Thus the speculative suggestion is appeared that the Ovatoscutum is pelagic Hydrozoa
Hydrozoa
Hydrozoa are a taxonomic class of very small, predatory animals which can be solitary or colonial and which mostly live in saltwater. A few genera within this class live in freshwater...

 Chondrophora, which became popular and was widely quoted despite absence of additional researches and facts.
As far back as 1966 Glaessner and Wade remarked that no evidence of a velellid 'sail' exists in Ovatoscutum and that Ovatoscutum differs from all Porpitidae chondrophora.

Ovatoscutum fossils are negative imprints on the bases of sandstone beds with the "elephant skin" and tubercle texture diagnostic of microbial mats. The same bedding planes contain various other benthic organisms: Yorgia
Yorgia
Yorgia waggoneri is a member of the Ediacara biota, and resembles a cross between the organisms Dickinsonia and Spriggina. It has a low, segmented body consisting of a short wide "head", no appendages, and a long body region, reaching a maximum length of...

, Andiva, 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...

, Tribrachidium
Tribrachidium
Tribrachidium heraldicum was an early Ediacaran organism famous for its unusual tri-radial symmetry. It was named and first described from South Australia by Martin Glaessner and Brian Daily in 1959....

, Kimberella
Kimberella
Kimberella is a monospecific genus of bilaterian known only from rocks of the Ediacaran period. The slug-like organism fed by scratching the microbial surface on which it dwelt in a manner similar to the molluscs, although its affinity with this group is contentious.Specimens were first found in...

, Parvancorina
Parvancorina
Parvancorina is a genus of shield-shaped Ediacaran fossils. It has a raised ridge down the central axis of symmetry. This ridge can be high in unflattened fossils. At the 'head' end of the ridge there are two quarter circle shaped raised arcs attached. In front of this are two nested...

and others. The such Ediacara-type assemblages are having bedding-planes that preserve benthic organisms that appear not to have been transported in the course of their burial and they preserved in situ
In situ
In situ is a Latin phrase which translated literally as 'In position'. It is used in many different contexts.-Aerospace:In the aerospace industry, equipment on board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may...

. This fact also does not support pelagic lifestyle and chondrophoran interpretation of the Ovatoscutum.

Mikhail A. Fedonkin
Mikhail A. Fedonkin
Dr. Mikhail Aleksandrovich Fedonkin is an awarding winning paleontologist specializing in documentation of the earliest animals' body fossils, tracks, and trails. He was the first to describe several fossils including Hiemalora, Onega stepanovi, and Nimbia occlusa.Fedonkin is fluent in English and...

 places Ovatoscutum in the extinct bilateria
Bilateria
The bilateria are all animals having a bilateral symmetry, i.e. they have a front and a back end, as well as an upside and downside. Radially symmetrical animals like jellyfish have a topside and downside, but no front and back...

n 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...

.
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