Ra. Askin, Manumiella seymourensis new species, a stratigraphically significant dinoflagellate cyst from the Maastrichtian of Seymour Island, Antarctica, J PALEONTOL, 73(3), 1999, pp. 373-379
The peridiniacean dinoflagellate cyst Manumiella seymourensis new species d
escribed herein characterizes Maastrichtian shallow marine sediments croppi
ng out on Seymour Island, northeastern Antarctic Peninsula. It dominates pa
lynological assemblages throughout the lower Maastrichtian (and possibly up
permost Campanian) to lower upper Maastrichtian part of the Lopez de Bertod
ano Formation. Despite its superficial similarity to some other southern mi
d to high paleolatitude Campanian-Maastrichtian species, M. seymourensis re
presents a discrete, biostratigraphically useful population of peridiniacea
n cysts. Its morphology and size parameters remain consistent throughout al
most all of its stratigraphic range, equated with relatively stable environ
mental conditions throughout much of the Maastrichtian in the James Ross Ba
sin. Morphological variations, equated with environmental change, are appar
ent in specimens in the lowermost and uppermost parts of its range.