ORIGINAL ARTICLE
Fossil zygospores of Zygnemataceae
and other microremains of freshwater algae
from two Miocene palaeosinkholes
in the Opole region, SW Poland
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Department of Palaeobotany, Władysław Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46,
PL-31-512 Kraków, Poland |
Online publication date: 2014-06-17
Publication date: 2014-06-17
Acta Palaeobotanica 2014; 54(1): 113–157
KEYWORDS
ABSTRACT
Algal microremains were encountered during palynological investigation of deposits filling two Miocene
palaeosinkholes excavated in the Tarnów Opolski and Górażdże quarries. Algal microfossils of 40 species
were identified, most of which are frequent non-pollen palynomorphs occurring in Neogene deposits. The microfossils
most frequently found in all studied samples belong to the genera Sigmopollis and Botryococcus. Both
algal assemblages contain a significant proportion of resting cells (zygospores = hypnozygotes) such as Cycloovoidites,
Diagonalites, Megatetrapidites, Ovoidites, Stigmozygodites, and Tetrapidites, probably fossil zygospores
of members of the Zygnemataceae family (Mougeotia, Spirogyra, Zygnema). Some specimens probably related
to desmid zygospores (Closteritetrapidites, Monopunctites, Planctonites), freshwater dinoflagellate cysts, and
Prasinophyceae (Leiosphaeridia) were found. Most of the identified fossilised remains of algae are often seen in
sediments indicating meso- to eutrophic conditions and are characteristic for stagnant or slowly flowing shallow
waters. Fossil algae of Pediastrum and Tetraedron genera were recorded in samples from the Górażdże palaeosinkhole,
suggesting small differences in the aquatic habitat (e.g. water depth) between ponds in the sinkholes.
Three new fossil species related to zygospores of the Zygnemataceae are described: Ovoidites vangeelii sp. nov.,
Tetrapidites grandis sp. nov., and Tetrapidites opolensis sp. nov.