Article: Giant acanthomorph acritarchs from the Upper Proterozoic in southern Norway

Large microfossils from a single phosphatic pebble in the late Riphean-early Vendian ( > 612+ 18 — 665+ 10 Ma) Biskopas Conglomerate in the Hedmark Group in southern Norway were described by Spjeldnaes (1963) under the name Papillomembrana compta and interpreted as a possible dasycladacean alga. The microfossils are evidently organic-walled and here regarded as giant acanthomorph acritarchs. The diagnosis of Papillomembrana compta is emended. Possibly related Proterozoic taxa are discussed. A new acanthomorph acritarch, Ericiasphaera spjeldnaesii gen. et sp. nov., found with P. compta within the same petrographic thin-section is described. Contrary to former conceptions, recent data seem to indicate that large complex acritarchs were common in late Proterozoic times.