Siliceous microfossils from the Upper Cambrian of Queensland

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Abstract
An unusually well preserved assemblage of siliceous microfossils of Mindyallan (early Late Cambrian) age is described from western Queensland. It is dominated by hexactinellid spicules. Among the forms identified as hexactinellid sponges are a new species of Konyrium Nazarov & Popov 1976, previously known only as enigmatic fossils from the Ordovician, and the new genus Silicunculus, characterized by hook-shaped spicules. Spiculated globules about 250 μm in diameter are interpreted as the skeletons of hexactinellid propagules and referred to the new genus Echidnina. Perforated globular tests 280–520 μm in diameter are referred to the genus Blastulospongia Pickett & Jell 1983,a presumed sphinctozoan sponge. Blastulospongia may alternatively be interpreted as a radiolarian similar to the spumellarian collosphaerids. The possibility of radiolarian affinities of Echidnina also is discussed, but considered less likely. Associated spicules, not referred to named taxa, are also described and figured. These include typical hexactinellid spicules as well as siliceous sclerites of unknown nature. Among the former are spicule types that indicate the presence of taxa related to the genera Multivasculatus Howell & Van Houten 1940, Rigbyella Mostler & Mosleh-Yazdi 1976 (? = Azyrtalia Nazarov 1973), and Nabaviella Mostler & Mosleh-Yazdi 1976. These genera were based on Late Cambrian species but their record probably ranges from the Early Cambrian