File:Nemiana simplex fossils in micaceous quartzose sandstone (Mogilev Formation, upper Neoproterozoic; Novodnestrovsky Quarry, Podolia, Ukraine) 2 (15204441252).jpg

Nemiana simplex individual on underside of micaceous quartzose sandstone slab from the Precambrian of Ukraine. (2.6 cm diameter)

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.

Stratigraphy: Yampol Member, Mogilev Formation, Balday Series, upper Vendian (= upper Ediacaran), upper Neoproterozoic

Locality: Novodnestrovsky Quarry, Podolia, Ukraine

Some info. from Andy Knoll (pers. comm.) & Jere Lipps (pers. comm.).

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]