| Quaestio Temporal range: Ediacaran | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Genus: | † Quaestio |
| Species: | †Q. simpsonorum |
| Binomial name | |
| †Quaestio simpsonorum | |
Quaestio is an early motile marine animal which lived 555 million years ago in the Upper Ediacaran. It is the earliest known animal to bear evidence of left-right asymmetry. The type species is Q. simpsonorum.
Fossil material of Quaestio was discovered in Southern Australia in 2024, from the Ediacara Member at Nilpena Ediacara National Park. [1] At least four trace fossils were discovered as well, some a few centimeters behind the death-mask of the maker, and some without their maker present, showing that the animal was capable of movement, which direction it moved and its anterior and posterior regions. [1] [2]
The generic name Quaestio is derived directly from the Latin word quaestio, meaning "question", in reference to the shape of the central ridge. The specific name simpsonorum is the Latinisation of the surname of philanthropists Mary Lou and Antony Simpson, in honor of their contributions to the research and conservation of Ediacaran fossil materials. [1]
Quaestio has a near smooth circular margin, broken by a V-shaped notch at the posterior end of the animal. In the center sits the main ridge, which forms a backwards question mark-like shape, with secondary ridges sitting between the main ridge and the outer margin. Quaestio can range in sizes of 3 cm to 8 cm in overall diameter, with the main ridge being 60% of the length of the body. [1]
Arkarua adami is a small, Precambrian disk-like fossil with a raised center, a number of radial ridges on the rim, and a five-pointed central depression marked with radial lines of five small dots from the middle of the disk center. Fossils range from 3 to 10 mm in diameter.
Dickinsonia is a genus of extinct organism, most likely an animal, that lived during the late Ediacaran period in what is now Australia, China, Russia, and Ukraine. It is one of the best known members of the Ediacaran biota. The individual Dickinsonia typically resembles a bilaterally symmetrical ribbed oval. Its affinities are presently unknown; its mode of growth has been considered consistent with a stem-group bilaterian affinity, though various other affinities have been proposed. It lived during the late Ediacaran. The discovery of cholesterol molecules in fossils of Dickinsonia lends support to the idea that Dickinsonia was an animal, though these results have been questioned.
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.
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.
Mawsonites is a fossil genus dating to the Ediacaran Period from 635 – 539 million years ago during the Precambrian era. The fossils consist of a rounded diamond shape, made up from lobes radiating out from a central circle roughly 12 cm in diameter. There are about 19 radiations from the central circle.
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.
Swartpuntia is a monospecific genus of erniettomorph from the terminal Ediacaran period, with at least three quilted, leaf-shaped petaloids — probably five or six. The petaloids comprise vertical sheets of tubes filled with sand. Swartpuntia specimens range in length from 12 to 19 cm, and in width from 11.5 to 140 cm. The margin is serrated, with a 1 mm wide groove. A 14 mm wide stem extends down the middle, tapering towards the top, and stopping 25 mm from the tip. The stem has a V-shaped ornamentation on it. The original fossils were found at, and named after, the Swartpunt farm between Aus and Rosh Pinah in Namibia. The generic name comes from Swartpunt, meaning black point in reference to the colour of the rocks. The specific name germsi honours Gerard Germs, who studied the Nama formation of geological beds.
Trilobozoa is a phylum of extinct, sessile animals that were originally classified into the Cnidaria. The basic body plan of trilobozoans is often a triradial or radial sphere-shaped form with lobes radiating from its centre. Fossils of trilobozoans are restricted to marine strata of the Late Ediacaran period.
The Ediacaranbiota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period. These were 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. The term "Ediacara biota" has received criticism from some scientists due to its alleged inconsistency, arbitrary exclusion of certain fossils, and inability to be precisely defined.
Eoandromeda is an Ediacaran organism consisting of eight radial spiral arms, and known from two taphonomic modes: the standard Ediacara type preservation in Australia, and as carbonaceous compressions from the Doushantuo formation of China, where it is abundant.
Coronacollina acula is a multicellular organism from the Ediacaran period resembling the Cambrian 'sponge' Choia. The organism comprised a raised, tri-radially-symmetrical central mound with a central depression and resistant spicules, which were resistant — either chitinous or biomineralized — and grew to be 37 cm long.
The Avalon explosion, named from the Precambrian faunal trace fossils discovered on the Avalon Peninsula in Newfoundland, eastern Canada, is a proposed evolutionary radiation of prehistoric animals about 575 million years ago in the Ediacaran period, with the Avalon explosion being one of three eras grouped in this time period. This evolutionary event is believed to have occurred some 33 million years earlier than the Cambrian explosion, which had been long thought to be when complex life started on Earth.
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.
Kimberichnus is an ichnofossil associated with the early bilaterian Kimberella. It is known mostly from shallow marine Ediacaran sediments, often occurring alongside its producer. Kimberichnus often occurs in Russia and South Australia, where it is most abundant in the shape of multiple arcuate sets of ridges with fan-shaped arrangements.
The Ediacaran fossil Hallidaya, a close relative of Skinnera lived in Belomorian of the Late Ediacaran period prior to the Cambrian explosion and thrived in the marine strata on the ocean floor of what is now considered Australia. These fossils were disk-shaped organisms that were slightly dome shaped with tri-radial symmetry. These Ediacaran organisms thrived by living in low-energy inner shelf, in the wave- and current-agitated shoreface, and in the high-energy distributary systems.
Obamus coronatus is a torus-shaped Ediacaran fossil from the Rawnsley Quartzite of South Australia named in honor of former American President Barack Obama by the lab of Mary L. Droser.
Ikaria wariootia is an early example of a wormlike, 2–7 mm-long (0.1–0.3 in) bilaterian organism. Its fossils are found in rocks of the Ediacara Member of South Australia that are estimated to be between 560 and 555 million years old. A representative of the Ediacaran biota, Ikaria lived during the Ediacaran period, roughly 15 million years before the Cambrian, when the Cambrian explosion occurred and where widespread fossil evidence of modern bilaterian taxa appear in the fossil record.
Attenborites janeae is a species of Ediacaran organism from South Australia first described by a team led by Palaeontologist Mary L. Droser in 2018. The genus Attenborites was named after Sir David Attenborough. The bed in which the first 52 specimens from Australia of A. janeae was given the ARB designation "Alice's Restaurant Bed", and has been given that nickname for its abundance of rare taxa and newly described ones and is also a reference to Arlo Guthrie's 1967 song, "Alice's Restaurant". The new taxon is unique from all of these other taxa in the way that it has a much more irregular morphology than the other 52 specimens.
Uncus dzaugisi is an extinct species of animal which lived 560 to 550 Ma during the late Ediacaran of Southern Australia. It is likely the earliest definitive ecdysozoan known. It is the only member of the genus Uncus.
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