''Saarina'' are cloudinimorph fossils from the

Ediacaran The Ediacaran ( ) is a geological period of the Neoproterozoic geologic era, Era that spans 96 million years from the end of the Cryogenian Period at 635 Million years ago, Mya to the beginning of the Cambrian Period at 538.8 Mya. It is the last ...

(

Vendian The Ediacaran ( ) is a geological period of the Neoproterozoic geologic era, Era that spans 96 million years from the end of the Cryogenian Period at 635 Million years ago, Mya to the beginning of the Cambrian Period at 538.8 Mya. It is the last ...

) and Early Cambrian marine deposits of

European Russia European Russia is the western and most populated part of the Russia, Russian Federation. It is geographically situated in Europe, as opposed to the country's sparsely populated and vastly larger eastern part, Siberia, which is situated in Asia ...

and Laurentia. They are tubes made up of stacked conical elements. These fossils are comparable to the dwelling tubes of

worm Worms are many different distantly related bilateria, bilateral animals that typically have a long cylindrical tube-like body, no limb (anatomy), limbs, and usually no eyes. Worms vary in size from microscopic to over in length for marine ...

s or

cnidaria Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...

ns.

Occurrence

Fossils of the type species, ''S. tenera'', were found in a core from the Gatchina No.13 borehole in the Leningrad Region, Russia. The most conspicuous deposits associated with these fossils are referred to as the Lomonosov Fm., Lontova Horizon, and lower Tommotian (= Cambrian Stage 2). ''S. kirsanovi'' fossils were found in a core from the Vorob'evo No.1 borehole,

Moscow Region Moscow Oblast (, , informally known as , ) is a federal subjects of Russia, federal subject of Russia (an oblast). With a population of 8,524,665 (Russian Census (2021), 2021 Census) living in an area of , it is one of the most densely populate ...

and in a core from the Malinovka borehole, near Obozersky in the Arkhangelsk Region. ''S. juliae'' was found in a core from the

Gavrilov-Yam Gavrilov-Yam () is a town and the administrative center of Gavrilov-Yamsky (or Gavrilov-Yamskiy) District in Yaroslavl Oblast, Russia, located on the Kotorosl River. Population: History The first mention of a settlement on the site of modern ...

No.5 borehole, Yaroslavl Region. The deposites with ''S. kirsanovi'' and ''S. juliae'' are referred to the Redkino Horizon, Upper Vendian (Ediacaran), and are about 558 mya old. They are also known from early Cambrian rocks in the USA.

Description

''Saarina'' was a tube-dwelling organism of unknown biological affinity, known from its siliciclastic deposits dating to the late

(Vendian) and lowest

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

of the Russian Platform. It was funnel-shaped, consisting of dense, thinly-walled and annulated, ringlike segments. The fossils are preserved in the substrate as a result of superficial mineralization during the early stages of decomposition. The fossils are typically found in

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

and preserved in the form of flat

pyrite The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue ...

ribbons as a result of superficial pyritization in the early stage of organic decomposition. ''Saarina'' tubes were cylindrical in form, conical at the base, consisting of funnel-shaped narrow rings. The wall of the tube was thin, originally organic-walled, not chitinous. The tubes attained widths up to 7 mm. The species of the ''Saarina'' differ mainly in the forms of the funnels: * ''S. tenera'' have straight conical funnels. * ''S. juliae'' have conical funnels, curved outward. * ''S. kirsanovi'' have funnels curved inward.

References

* {{Taxonbar, from=Q7395696 Ediacaran life Fossils of Russia Fortunian Cambrian genus extinctions

Occurrence

Description

See also

References