Abstract

GULER, M. Verónica; GUERSTEIN, G. Raquel  and  CASADIO, Silvio. New dinoflagellate cyst species from the Calafate Formation (Maastrichtian), Austral Basin, Argentina. Ameghiniana [online]. 2005, vol.42, n.2, pp.419-428. ISSN 1851-8044.

The aim of this paper is to erect four new dinoflagellate cyst species from the Maastrichtian Calafate Formation, Austral Basin, Argentina. Andalusiella spinosa sp. nov. is strongly acrocavate and possesses a periphragm covered with spines. Palaeocystodinium pilatum sp. nov. has a periphragm densely covered with fine, flexuous, hair-like projections, shortening towards the end of the horns, and a finely granulate endophragm. The large peridinialean Caligodinium perforatum sp. nov. shows the hypocystal archeopyle typical for the genus, with a simple triplacoid opercular piece and a microfoveolate autophragm surrounded by a perforate flocculent calyptra. Hafniasphaera australis sp. nov. is differentiated from other species of the genus Hafniasphaera by the presence of a distinctive anterior ventral process which emerges at the junction of paraplates 1', 4' and as. These new species characterize the assemblages from deposits related to the South Atlantic transgression that occurred during Maastrichtian times at the southermost part of Argentina.

Keywords : Dinoflagellate cysts; Maastrichtian; Calafate Formation; Austral Basin; Argentina.