Nemiana simplex
Ediacaran organisms are some of the most celebrated
and problematic fossils in the rock record. The most famous Ediacarans
are creatures (animals?) such as Dickinsonia, Spriggina, and Tribrachidium.
The most widely-available Ediacaran material in the
retail fossil trade is Nemiana simplex Paliy, 1976 from Ukraine.
Fossils of this organism are small to moderately large, circular to subcircular
masses on the undersides of sandstone beds (convex hyporelief; most Ediacaran
macrofossils are preserved on the soles of sandstone beds). Many
Nemiana specimens show a subtle concentric wrinkling.
Paliy (1976) identified it as a coelenterate (?)
incertae sedis. It’s similar to the sea anemone trace fossil Bergaueria.
This similarity has prompted many to consider Nemiana fossils as the
undersides of sea anemones. But, if it is a burrowing sea anemone, it’s
odd why there’s no central puckered structure (cf. Bergaueria).
Others suggest that Nemiana may represent
siphonocladalean chlorophyte algae similar to the living Ventricaria (“Valonia”) (Siphonocladaceae). Such
green algae are commonly called “ball algae” or “sailor's eye balls” or “bubble
algae” or “sea pearls”. Individual ~spheres of such algae are large
single cells. In & out of water, these huge cells have surprising
rigidity (they can even bounce off countertops & floors like
superballs). So, Nemiana may not be an animal at all.
Locality:
Novodnestrovsky Quarry, Podolia, Ukraine.
Stratigraphy: Yampol Member, Mogilev Formation, Balday Series, upper Vendian (=
upper Ediacaran), upper Neoproterozoic.
Nemiana simplex on underside of micaceous quartzose sandstone slab
(12.7 cm across at widest) from the Mogilev Formation (upper Neoproterozoic) at
the Novodnestrovsky Quarry, Podolia, Ukraine.
Nemiana simplex individual (2.6 cm diameter) on underside of
micaceous quartzose sandstone from the Mogilev Formation (upper Neoproterozoic)
at the Novodnestrovsky Quarry, Podolia, Ukraine.
Some info. from Andy Knoll & Jere Lipps.
Some info. from Paliy (1976) & Paliy et al.
(1979):
Paliy, V.M. 1976.
Остатки
бесскелетной
фауны и следы
жизнедеятелъности
из отложений
верхнего докембрия
и нижнего
кембрия
Подолии [Ostatki besskeletnoy fauny i
sledy zhiznedeyatelnosti iz otlozheniy verkhnego dokembriya i nizhnego kembirya
Podolii] [Remains of unskeletonized faunas and traces of life activity from
Upper Precambrian and Lower Cambrian deposits in Podolia]. pp. 63-77,
149-154, 160-161, pls. 21-28 in Палеонтология
и
Стратиграфия
Верхнего Докембрия
и Эижнего
Палеозоя
Юго-Запада Восточно-Европейской
Платформы [Paleontologiya
i Stratigrafiya Verkhnego Dokembriya i Nizhnego Paleozoya Yugo-Zapada
Vostochno-Europeyskoy Platformy] [Upper Precambrian and Lower
Paleozoic Paleontology and Stratigraphy of the Southwestern East-European
Platform]. Kiev. Naukova Dumka. [in Russian]
Paliy, V.M., E. Posti & M.A. Fedonkin.
1979.
Мягкотелые
Метазоа и
ископаемые
следы
животных
венда и
раннего
кембрия [Myagkotelye Metazoa i
iskopaemye sledy zhivotnykh venda i rannego kembriya] [Soft-bodied Metazoa and
trace fossils from the Vendian and Lower Cambrian]. pp. 49-82, 103-108,
205-208, pls. 48-68 in Палеонтология
Верхнедокембрийских
и кембрийских
Отложений
Востчно-Европейской
Платформы [Paleontologiya
Verkhnedokembriyskikh i Kembriyskikh Otlozheniy Vostochno-Europeyskoy Platformy]
[Paleontology of Upper Precambrian and Cambrian Deposits in the
East-European Platform]. Moscow. Izdatelstvo “Nauka”.
[in Russian]