Ostracods from the Upper Valanginian and Upper Hauterivian of the Sundays River Formation, Algoa basin, South Africa

• V.H. Valicenti ^[1] ; J.M. Stephens ^[2]
  1. [1] Soekor, Johannesburg, South Africa
  2. [2] Soekor, P.O. Box 3087, Johannesburg, 2000, South Africa
• Localización: Revista española de micropaleontología, ISSN 0556-655X, Vol. 16, Nº. 1-3, 1984, págs. 171-239
• Idioma: inglés
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• Resumen

  • The study is based mainly on outcrop samples of the marine Lower Cretaceous Sundays River Formation but makes use also of a small amount of material from boreholes already recorded in the literature. Thirty six species of Ostracoda are recorded of which 21 are described. Of these, 15 are new species, 3 are left in open nomenclature and 3 are re-described.

    Two main assemblages are recognised. The lowermost, of Upper Valanginian age, is characterised by Cytherella algoaensis Brenner and Oertli, C. inaequivalva Dingle, Cytherelloidea coegensis Dingle, C. agyroides Dingle, Cytheropteron sagittarium sp.nov., Sondagella valanginiana sp.nov., Paranotacythere (P.) parva sp.nov., P. (P.) dimorphica sp.nov. and 13 accompanying species. The uppermost assemblage, of Upper Hauterivian age, is characterised by Procytherura dinglei Brenner and Oertli, Sondagella colchesterensis sp.nov., Looneyella reticulata sp.nov., Eucytherura (V.) tuberculata Brenner and Oertli and Bythocypris nodosa Brenner and Oertli. The lowermost assemblage is interpreted as having been deposited in a stable shallow, temperate marine environment and the upper- most assemblage is interpreted as representing a re-stabilization of ecological conditions in the basin after a sudden deepening and cooling at the onset of the Hauterivian.

    These assemblages have allowed the outcrop sections to be dated and correlated.