A new species of small acritarch with porous wall structure from the early Cambrian of Estonia, and implications for the fossil record of eukaryotic picoplankton

• The Proterozoic-Phanerozoic transition records a general trend of decrease in phytoplankton cell size, in contrast tothe earlier and much larger Ediacaran acritarchs. Particularly minute, unornamented but sculptured organic-walledmicrofossils have been recovered from the lower Cambrian Lükati Formation in northern Estonia. The lack of anysignificant thermal alteration in the formation allowed for excellent preservation of fine microstructures on thesemicrofossils. Among the rich palynomorph assemblage in Lükati, a new species of tiny, spheroidal eukaryoticmicrofossil is recorded: Reticella corrugata gen. et sp. nov. It is characterised by a corrugated and flexible vesicle wallthat is densely perforated by nano-scale pores. Despite its unique morphology, the new species shares diagnosticcharacters with fossil and extant prasinophyte algae. R. corrugata is among the smallest microfossils with typicaleukaryotic morphology (conspicuous wall sculpture) and contributes to the diversity of the size class of smallacritarchs. Size, abundance, inferred prasinophyte affinity and eukaryotic wall sculpture make this new taxon alikely member of the early eukaryotic picoplankton.

Subject headings

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Geologi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geology (hsv//eng)

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

Keyword

Cambrian

Estonia

organic-walled microfossils

picoplankton

prasinophytes

small acritarchs

Earth Science with specialization in Historical Geology and Palaeontology

Geovetenskap med inriktning mot historisk geologi och paleontologi

Publication and Content Type

ref (subject category)

art (subject category)