Elżbieta Turnau

Givetian palynostratigraphy and palynofacies: new data from the Bodzentyn Syncline (Holy Cross Mountains, central Poland)

Givetian samples have yielded well preserved palynomorphs including miospores, prasinophytes, acritarchs, and coenobial algae. Two new miospore species (Grandispora parvula Turnau, sp. nov. ,a ndPerotrilites granulaticonatus Turnau, sp. nov.), and two new prasinophyte species (Dictyotidium obesum Turnau, sp. nov. ,a ndPolyedrixium skalensis Turnau, sp. nov.) are described. Ten possibly new miospore and prasinophyte forms are described but not specifically named. Two miospore zones of the East European zonal division are distinguished. The direct conodont and goniatite data indicate that the first appearances of (1) Chelinospora concinna ,( 2)Daillydium pentaster ,( 3)Samarisporites triangulatus ,a nd (4)Ancyrospora incisa are: upper Lower, or Middle varcus Subzone for (1); Middle varcus Subzone for (2) and (3); and above the base of the hermanni‐cristatusZone for (4). Four successive palynofacies are described: (i) a spore-dominated palynofacies lacking in acritarchs; (ii) palynofacies with acritarchs; (iii) palynofacies with abundant leiospheres; (iv) palynofacies dominated by tasmanitids. The palynofacies changes are possibly related to the eustatic sea-level fluctuations, but the pattern is obviously complicated by changes in surface water circulation and =or fertility.

Miospore stratigraphy of Middle Devonian deposits from western Pomerania

Abstract Middle Devonian miospore assemblages from subsurface of Western Pomerania are assigned to the Rhabdosporites langii and Aneurospora extensa zones of the East European miospore zonation scheme. Late Eifelian and early to middle Givetian ages of the host deposits are suggested. Two new species, Corystisporites undulatus Turnau sp. nov. and Verrucosisporites flexibilis Turnau sp. nov. are described, and three new taxonomic combinations, Aneurospora extensa (Naumova) Turnau, comb. nov., Corystisporites acutispinosus (Fuglewicz et Prejbisz) Turnau, comb. nov. and Kraeuselisporites violabilis (Tchibrikova) Turnau, comb. nov. are proposed.

Size distribution in some Middle Devonian dispersed spores and its bearing on the problem of the evolution of heterospory

Abstract Some Middle Devonian dispersed spore species have been studied whose size range embraces the arbitrary demarcation line of 200 μm in diameter generally accepted for the identification of a megaspore. The spore size distribution for one species is unimodal while those for other three species are bimodal. The spores of the smaller size classes (the presumed microspores) are relatively large, the means being 90 μm, 100 μm and 207 μm. The morphological features of the spores imply their progymnospermous affinity. It is suggested that in progymnosperms, in the course of heterospory evolution, the increase in spore size occurred before size differentiation and, presumably, before sex determination. The cause of the size increase might have been endospory, which may thus have occurred previous to the last two events.

New dispersed seed-megaspores from the mid-Givetian of European Russia

Abstract New genus and species of dispersed megaspore tetrads, consisting of one large (presumably fertile) and three small (presumably aborted) spores, are described from mid-Givetian deposits of European Russia. These are probably the oldest seed-megaspores recorded so far. The new taxon is Granditetraspora zharkovae gen. et sp. nov. A progymnosperm affinity for the fossil is suggested. It is also implied that the parent plants of the described seed-megaspores arose from ancestors that displayed only a low grade of heterospory.

Two new Devonian spore genera from Euramerica and their stratigraphic and geographic distribution

Two new genera of cavate spores, Tergobulasporites and Crumenasporites, are established for the Devonian of Euramerica to accommodate species previously included in inappropriate acavate spore genera. The new genera are restricted to Euramerica. The first entry of Tergobulasporites immensus (Nazarenko et Nekryata) comb. nov. is synchronous over a wide area of central and eastern Europe and is a good palynostratigraphic marker for the Famennian crepida Conodont Zone. Tergobulasporites immensus is widely distributed along the southeastern and southern margin of the Old Red Sandstone Continent, while Crumenasporites has been recorded only from its northern perimeter. Spores included in both genera possess a gula which may suggest they are megaspores.