Lower ordovician palynomorphs from the Acoite formation, Northwestern Argentina

Abstract

Thirty‐six taxa of moderately abundant and relatively well‐preserved acritarchs, algae, chitinozoans, scolecodonts and graptolite siculae from the Acoite Formation, northwestern Argentina, are described. Two new acritarch species, Ammonidium ballistum Ottone and Baltisphaerosum peniguelii Ottone, together with one new combination, Adorfia hoffmanensis (Cramer et al. 1974) Ottone, are proposed. Two distinct palynomorph assemblages have been differentiated throughout the unit: (1) a Lower Acoite Palynological Assemblage, early Arenigian in age; and (2) an Upper Acoite Palynological Assemblage, referred to the middle Arenigian. Both palynological assemblages appear to be related to the Mediterranean or Perigondwanian Paleoprovince and thus represent a high latitudinal plankton assemblage.