Ventogyrus
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''Ventogyrus'' is an
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 ...
fossil found in the
White Sea The White Sea (; Karelian language, Karelian and ; ) is a southern inlet of the Barents Sea located on the northwest coast of Russia. It is surrounded by Karelia to the west, the Kola Peninsula to the north, and the Kanin Peninsula to the nort ...
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Arkhangelsk Arkhangelsk (, ) is a types of inhabited localities in Russia, city and the administrative center of Arkhangelsk Oblast, Russia. It lies on both banks of the Northern Dvina near its mouth into the White Sea. The city spreads for over along the ...
region of
Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
. It was first discovered in the Teska member of the Ust'-Pinega formation, in a thick lens of sandstone, originally sand dumped by storm waves that cut a deep channel through the shallow sea bottom where the organisms lived. Many individuals were preserved on top of each other, often torn or in distorted positions. As a result, it was originally thought to have had a "boat shaped" form and to have lived anchored in the sea floor. However, a nearby site discovered later by Mikhail Fedonkin yielded separate specimens which were beautifully preserved in an upright position and showed the internal anatomy. ''Ventogyrus'' is now believed to have lived on or above the sea floor, an egg-shaped organism made of three modules (like the sections of an orange), all connected to a central rod. This three-fold, or triradial, symmetry is not usually found in the living world today, but it is also seen in other Ediacarans. The whole organism was wrapped by an external membrane. Individual fossils are approximately 6 cm in diameter and 12 cm long. Fedonkin and Ivantsov suggested there was a stalk attached to the body of ''Ventogyrus''. Specimens with an intact basal side show the presence of a triangular cross-section with a circular structure in the center. It is possible this is where a stalk may have attached. Such a structure could have tethered ''Ventogyrus'' to the sea floor, or hung down to stabilize its position in the water column. Unidentifiable fossil fragments that could have been the remains of stalks were associated with the specimens. ''Ventogyrus'' is unique among Ediacaran fossils because so many have been preserved in three dimensions. The quality of its complex anatomical preservation is also unique among Ediacarans. This preservation allows paleontologists to more accurately conceive of how it, and other species similar in morphology, lived in and interacted with its environment.


Internal anatomy

Inside the body, a single long wall divides each module in half. Attached to these walls are numerous
transverse Transverse may refer to: *Transverse engine, an engine in which the crankshaft is oriented side-to-side relative to the wheels of the vehicle *Transverse flute, a flute that is held horizontally * Transverse force (or ''Euler force''), the tangen ...
walls which divide the modules into chambers of decreasing size. The chambers are divided with the "gliding symmetry" common to many Ediacarans: the elements are offset from each other in an alternating sequence rather than showing
bilateral symmetry Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria. External symmetry can be easily seen by just looking at an organism. For example, the face of a human being has a plane of symme ...
across the dividing wall. A single undivided chamber is at the base of each module. It is thought that the internal chambers of ''Ventogyrus'' could have been filled with gas or bodily fluids. These chambers are only preserved when they are filled with sand, indicating that there may have been no cellular material within. The purpose of gas chambers within ''Ventogyrus'' would likely have been for
buoyancy Buoyancy (), or upthrust, is the force exerted by a fluid opposing the weight of a partially or fully immersed object (which may be also be a parcel of fluid). In a column of fluid, pressure increases with depth as a result of the weight of t ...
to stay in an upright position, and possibly to float above the sea floor. ''Ventogyrus'' also has three distinct longitudinal channels running along the central rod connecting the three modules. Each of these channels branches, and the branches move outward through the body, branching repeatedly to make up an internal network. It is possible this network was a
circulatory system In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. It includes the cardiovascular system, or vascular system, that consists of the heart ...
.


Relationships

Paleontologists have suggested different affiliations for ''Ventogyrus.'' Some follow Dolf Seilacher's theory that Ediacarans including ''Ventogyrus'' are an extinct phylum, the Vendobionta, related to no other living things. ''Ventogyrus'' is unusual among organisms proposed as vendobionts because paleontologists have also suggested relationships with post-Ediacaran fossils, including '' Erytholus'' from the
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 ...
. Fedonkin has suggested, based on details of internal anatomy, that ''Ventogyrus'' could have been the float organism of a
siphonophore Siphonophorae (from Ancient Greek σίφων (siphōn), meaning "tube" and -φόρος (-phóros), meaning "bearing") is an order within Hydrozoa, a class of marine organisms within the phylum Cnidaria. According to the World Register of Marine ...
colony (living examples include the
Portuguese Man O' War The Portuguese war (''Physalia physalis''), also known as the man-of-war or bluebottle, is a marine hydrozoan found in the Atlantic Ocean and the Indian Ocean. It is the only species in the genus ''Physalia'', which in turn is the only genus in ...
). This reconstruction would make it a member of the phylum
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, ...
, related to jellyfish and corals. He has also suggested it could be related to animals in the early Cambrian
Small Shelly Fauna The small shelly fauna, small shelly fossils (SSF), or early skeletal fossils (ESF) are mineralized fossils, many only a few millimetres long, with a nearly continuous record from the latest stages of the Ediacaran to the end of the Early Cambri ...
whose "shells" were internal body supports. Ivantsov considers it an early representative of the phylum
Ctenophora Ctenophora (; : ctenophore ) is a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), and they are ...
, the comb jellies, an ancient group whose members resemble but are not related to
jellyfish Jellyfish, also known as sea jellies or simply jellies, are the #Life cycle, medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animal ...
. ''Ventogyrus'' does not fall obviously within one of the main
form taxa Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of sc ...
of Ediacarans, the
rangeomorph The rangeomorphs are a group of Ediacaran Ediacaran biota, fossils. Ediacarans are the oldest large fossil organisms on earth, and many are not self-evidently related to anything else that has ever lived. However, some Ediacarans clearly resemble ...
s, the
erniettomorph The Erniettomorphs are a form of Ediacaran fossil consisting of rows of airbed-like tubes arranged along a midline with a glide symmetry, vaguely resembling plant leaves in shape. Representative genera include '' Ernietta'', ''Phyllozoon'', ''Pte ...
s, and the
trilobozoa Trilobozoa, from Ancient Greek τρεῖς (''treîs''), meaning "three", λοβός (''lobós''), meaning "lobe", and ζῷον (''zôion''), meaning "animal", is a phylum of extinct, sessile animals that were originally classified into the Cnid ...
ns, but it is also not obviously a member of a known biological
taxon In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
. While there is better information about the form of the living organism for ''Ventogyrus'' than almost any other Ediacaran, there is currently no consensus on what it was. However, investigators agree it was an animal.


Fossil endangerment through piracy

Findings from studies on fossils from the Arkhangelsk region have been published in many popular science magazines and newspapers. These fossils have also been exhibited in the museums in
Moscow Moscow is the Capital city, capital and List of cities and towns in Russia by population, largest city of Russia, standing on the Moskva (river), Moskva River in Central Russia. It has a population estimated at over 13 million residents with ...
,
St. Petersburg Saint Petersburg, formerly known as Petrograd and later Leningrad, is the second-largest city in Russia after Moscow. It is situated on the River Neva, at the head of the Gulf of Finland on the Baltic Sea. The city had a population of 5,601, ...
, and Arkhangelsk. Due to this exposure, there has been an interest in collecting them, legally and illegally. Illegal sales often take place over the internet. Many scientific papers have contained data from fossils which were obtained illegally.


References

{{Taxonbar, from=Q4107236, from2=Q25495259 White Sea fossils Fossils of Russia Ediacaran life Ediacaran Europe