Ventogyrus

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Ventogyrus
Temporal range: 635–542  Ma
Ventogyrus.jpg
A Ventogyrus fossil
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Superphylum:† Vendobionta
Genus:† Ventogyrus
Ivantsov and Grazhdankin 1997
Species
  • Ventogyrus chistyakoviIvantsov and Grazhdankin 1997

Ventogyrus is an Ediacaran fossil found in the White Sea-Arkhangelsk region of Russia. 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. [1]

Contents

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. [2]

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. [3] Unidentifiable fossil fragments that could have been the remains of stalks were associated with the specimens. [1]

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. [3] This preservation allows paleontologists to more accurately conceive of how it, and other species similar in morphology, lived in and interacted with its environment.

An artist's interpretation of Ventogyrus as an organism tethered to the seafloor. Ventogyrus chistyakovi recon.jpg
An artist's interpretation of Ventogyrus as an organism tethered to the seafloor.

Internal anatomy

Inside the body, a single long wall divides each module in half. Attached to these walls are numerous transverse walls which divide the modules into chambers of decreasing size. [3] 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 across the dividing wall. [1] 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 to stay in an upright position, and possibly to float above the sea floor. [3]

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. [3]

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. [2] Fedonkin has suggested, based on details of internal anatomy, that Ventogyrus could have been the float organism of a siphonophore colony (living examples include the Portuguese Man O' War). This reconstruction would make it a member of the phylum Cnidaria, related to jellyfish and corals. He has also suggested it could be related to animals in the early Cambrian Small Shelly Fauna whose "shells" were internal body supports. Ivantsov considers it an early representative of the phylum Ctenophora, the comb jellies, an ancient group whose members resemble but are not related to jellyfish. Ventogyrus does not fall obviously within one of the main form taxa of Ediacarans, the rangeomorphs, the erniettomorphs, and the trilobozoans, but it is also not obviously a member of a known biological taxon. 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. [1]

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, St. Petersburg, 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. [4] Many scientific papers have contained data from fossils which were obtained illegally. [4]

Related Research Articles

<i>Dickinsonia</i> Extinct genus of early animals

Dickinsonia is an extinct genus of basal animal that lived during the late Ediacaran period in what is now Australia, China, India, Russia and Ukraine. The individual Dickinsonia typically resembles a bilaterally symmetrical ribbed oval. Its affinities are presently unknown; its mode of growth is consistent with a stem-group bilaterian affinity, though some have suggested that it belongs to the fungi, or even an "extinct kingdom". The discovery of cholesterol molecules in fossils of Dickinsonia lends support to the idea that Dickinsonia was an animal.

<i>Kimberella</i> Genus of molluscs

Kimberella is an extinct 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 gastropods, although its affinity with this group is contentious.

<i>Tribrachidium</i> Extinct genus of invertebrates

Tribrachidium heraldicum is a tri-radially symmetric fossil animal that lived in the late Ediacaran (Vendian) seas. In life, it was hemispherical in form. T. heraldicum is the best known member of the extinct group Trilobozoa.

<i>Yorgia</i> Extinct species of disc-shaped organism

Yorgia waggoneri is a discoid Ediacaran organism. It has a low, segmented body consisting of a short wide "head", no appendages, and a long body region, reaching a maximum length of 25 cm (9.8 in). It is classified within the extinct animal phylum Proarticulata.

<i>Cephalonega</i> Extinct genus of invertebrates

Cephalonega stepanovi is a fossil organism from Ediacaran deposits of the Arkhangelsk Region, Russia. It was described by Mikhail A. Fedonkin in 1976

Rangea Fossil taxon

Rangea is a frond-like Ediacaran fossil with six-fold radial symmetry. It is the type genus of the rangeomorphs.

<i>Parvancorina</i>

Parvancorina is a genus of shield-shaped bilaterally symmetrical fossil animal that lived in the late Ediacaran seafloor. It has some superficial similarities with the Cambrian trilobite-like arthropods.

<i>Vendia</i> Fossil taxon

Vendia is a genus of oval-shaped, Ediacaran fossils ranging from 4.5 to 12.5 mm long. The body is completely segmented into isomers, which are arranged alternately in two rows longitudinal to the axis of the body. The larger isomers cover the smaller ones externally but the posterior ends of all the isomers remain free. The transverse elements decrease in size from anterior to posterior and are all inclined in the same direction.

Ediacaran biota All organisms of the Ediacaran Period (c. 635–541 Mya)

The Ediacaranbiota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period. These were composed of enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms.

<i>Albumares</i> Extinct genus of soft-bodied animals

Albumares brunsae is a tri-radially symmetrical fossil animal that lived in the late Ediacaran (Vendian) seafloor. It is a member of the extinct group Trilobozoa.

<i>Anfesta</i> Extinct genus of marine invertebrates

Anfesta stankovskii is a tri-radially symmetrical fossil animal that lived in the late Ediacaran (Vendian) seafloor. It is a member of the extinct group Trilobozoa.

Proarticulata Extinct phylum of animals

Proarticulata is a proposed phylum of extinct, bilaterally symmetrical animals known from fossils found in the Ediacaran (Vendian) marine deposits, and dates to approximately 567 to 550 million years ago. The name comes from the Greek προ = "before" and Articulata, i.e. prior to animals with true segmentation such as annelids and arthropods. This phylum was established by Mikhail A. Fedonkin in 1985 for such animals as Dickinsonia, Vendia, Cephalonega, Praecambridium and currently many other Proarticulata are described.

<i>Rugoconites</i> Extinct genus of invertebrates

Rugoconites is a genus of Ediacaran biota found as fossils in the form of a circular or oval-like impression preserved in high relief, six or more centimeters in diameter. The fossils are surrounded by frills that have been interpreted as sets of tentacles. The bifurcating radial ribs, spreading from a central dome, serve to distinguish this genus from the sponge Palaeophragmodictya, and may represent the channels of the gastrovascular system. Fossils of Rugoconites have been interpreted as early sponges, although this is countered by Sepkoski et al. (2002), who interpreted the organism as a free-swimming jellyfish-like cnidarian; similar to Ovatoscutum. However, the fossil is consistently preserved as a neat circular form and its general morphology does not vary, therefore a benthic and perhaps slow-moving or sessile lifestyle is more likely. Ivantstov & Fedonkin (2002), suggest that Rugoconites may possess tri-radial symmetry and be a member of the Trilobozoa.

Vendiamorpha Extinct class of simple animals

Vendiamorpha is a class of extinct animals within the Ediacaran phylum Proarticulata.

Isomer (Proarticulata)

Isomer is an element of transverse body articulation of the bilateral fossil animals of the Phylum Proarticulata from the Ediacaran (Vendian) period. This term has been proposed by Andrey Yu. Ivantsov, a Russian paleontologist from the Laboratory of the Precambrian organisms, Paleontological Institute, Russian Academy of Sciences.

<i>Andiva</i> Vendian fossil

Andiva ivantsovi is a Vendian fossil, identified to be a bilaterian triploblastic animal in the Ediacaran phylum Proarticulata, known from the Winter Coast, White Sea, Russia. It was first discovered in 1977, and described as a new species in a new genus by Mikhail Fedonkin in 2002. It lived about 555 million years ago. Fossils of Andiva also occur in South Australia. All known fossils of Andiva are external molds.

<i>Veprina</i>

Veprina is a rare Ediacaran coelenterate cnidarian found on the Zimny coast of the White Sea, Russia and was first described by Mikhail Fedonkin in 1980.

Petalonamae Proposed extinct group of animals

The petalonamids (Petalonamae) are an extinct group of archaic animals typical of the Ediacaran biota, also called frondomorphs, dating from approximately 635 million years ago to 516 million years ago. They are benthic and motionless animals, that have the shape of leaves, fronds (frondomorphic), feathers or spindles and that at first were considered algae, octocorals or sea pens, but now it is believed that they did not leave current descendants and that they would have a probable relation with the Ediacaran animals called Vendozoans.

<i>Archaeaspinus fedonkini</i>

Archaeaspinus fedonkini is an extinct proarticulatan organism from the Late Precambrian (Ediacaran) period.

Cephalozoa Extinct class of marine animals

Cephalozoa are an extinct class of primitive segmented marine animals from the Edicarian period. They possessed bilateral symmetry and were characterized by a thin, rounded body.

References

  1. 1 2 3 4 Fedonkin, Mikhail, James Gehling, Kathleen Grey, Guy Narbonne, and Patricia Vickers-Rich (2007). The Rise of Animals. Baltimore: Johns Hopkins University Press. pp. 143–145. ISBN   978-0-8018-8679-9.{{cite book}}: CS1 maint: multiple names: authors list (link)
  2. 1 2 Retallack, Gregory (15 November 2011). "Problematic megafossils in Cambrian palaeosols of South Australia". Palaeontology. 54 (6): 1223–1242. doi:10.1111/j.1475-4983.2011.01099.x. S2CID   130692406.
  3. 1 2 3 4 5 Fedonkin, M. A.; Ivantsov, A. Y. (1 January 2007). "Ventogyrus, a possible siphonophore-like trilobozoan coelenterate from the Vendian Sequence (late Neoproterozoic), northern Russia". Geological Society, London, Special Publications. 286 (1): 187. Bibcode:2007GSLSP.286..187F. doi:10.1144/SP286.14. S2CID   128927444 . Retrieved 4 June 2018.
  4. 1 2 Fedonkin, Mikhail (2009). "Paleo-piracy endangers Vendian (Ediacaran) fossils in the White Sea - Arkhangelsk region of Russia" (PDF). Notebooks on Geology. 03: 105. Retrieved 6 June 2018.
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