Abstract

Geochemical analyses of specimens of Reduviasporonites suggests that it is most likely of algal, rather than fungal origin. As probable alga, Reduviasporonites is unlikely to be integral to the process of mass extinction occurring at or near the Permian Triassic boundary, as suggested by Visscher and other workers because it cannot have acted as a saprophytic metaboliser of dead vegetation resulting from that event. Moreover, it ranges outside the postulated time of mass extinction by at least 10 million years Optical and electron microscopy of topotype material confirms that Reduviasporonites Wilson 1962 is the senior synonym of Chordecystia Foster 1979, and Tympanicysta Balme 1980. More over the type species of the last two genera, assigned in 1999 to Reduviasporonites by Elsik as R. chalastus (Foster) and R stoschianus (Balme), are conspecific. The type species, R catenulatus Wilson 1962, differs from R. chalastus in that its constituent cells are significantly smaller, more rounded, and have less well developed connecting areas (terminal rims) between cells. Brazilea helbyi forma gregata Foster 1979, recorded only from the type material of R. chalastus, is likely to be a junior synonym of that taxon.

The stratigraphic occurrences of the species of Reduviasporonites suggest that R. catenulatus is most common in the Wordian (Kazanian) of Oklahoma, though specimens of the size range associated with R. catenulatus are present very rarely in the Early Triassic Mazzin Member of the Werfen Formation, Austria. R chalastus is present in Capitanian to Griesbachian rocks spanning at least 10 million years, and outside the more narrow age span of the Permian–Triassic boundary. The size of the constituent cells present in R. chalastus appears to be related to paleolatitude with large examples occurring in the paleotemperate Permian of China, Russia, and Australia (Moura) and smaller specimens occurring in the paleotropical and paleoequatorial Permian of northern Australia, Saudi Arabia, United Kingdom and Austria.

You do not currently have access to this article.