Late Devonian acritarchs from the Carnarvon Basin, Western Australia

Organic-walled remains of marine microphytoplankton (acritarchs) are the predominant palynoftoral elements of sub-surface sediments belonging to the Gneudna Formation in the Carnarvon Basin of Western Australia. This study is based upon cored sections of the lower part of the formation as developed typically in the Merlinleigh Sub-basin of the eastern Carnarvon Basin. The acritarch palynoftora is abundant, diverse, and well-preserved; there are fifty-six species, only a small proportion of which are identifiable with previously described species. These latter suggest a Frasnian age for the Gneudna Formation, in agreement with the consolidated faunal evidence. The acritarch species are distributed among thirty-six genera, seven of which are newly instituted herein, viz. Alocomurus, Del/%soma, Gneudnaella, HislOpalla, Loma/olopas, Papulogaba/a, and Somphophragma. The following species are formally described and named as new: Alocomurus compac/us (type species), Cymatiosphaera spicigera, C. sub/rita, Del/%soma in/onsum (type species), Dic/yo/idium confragum, D. granula/um, D. prola/um, D. /orosum, Elek/oriskos /enuis, Evillia geome/rica, Florisphaeridium micidum, Gneudnaella psi/a/a (type species), Gorgonisphaeridium abs/rusum, G. carnarvonense, G. condensum, G. discissum, G. vesculum, Helosphaeridium gulla/um, H. microclava/um, His/opalla capillosa (type species), Loma/olopas cellulosa (type species), Lophosphaeridium deminu/um, L. segregum, Melikeriopalla venulosa, Navifusa exi/is, Papulogaba/a annula/a (type species), Rugale/es vie/us, Saharidia lusca, Solisphaeridium inaffec/um, Somphophragma miscellum (type species), Synsphaeridium ca/enarium, Tunisphaeridium flaccidum, and Veryhachium colemanii.