UPDATE ON THE NORTHERN AUSTRALIAN CAMBRIAN SPONGES RANKENELLA, JAWONYA AND WAGIMA

New material from the Ordian to early Templetonian (early Middle Cambr ian) of the Georgina Basin and Daly Basin in northern Australia allows further observations on the anthaspidellid sponge Rankenella mors and the chambered heteractinide sponge Jawonya gurumal respectively. Expl anate specimens of R. mors are found to bear closely spaced, rimmed os cules, and the known range of the species is extended from the Ranken Limestone near Soudan to include the Arthur Creek Formation near Ammar oo. Jawonya gurumal from the Tindall Limestone near Claravale is bette r preserved than type and topotype material, and demonstrates that the genus is two-walled, and not one-walled as originally described. Furt hermore, exopore architecture is much more complex than previously env isaged. The co-occurring related genus Wagima is also considered to be two-walled. Rankenella in the Ranken Limestone flourished in a tow-en ergy, shallow subtidal marine environment subject to episodic higher-e nergy events that generated ooid shoals and flat-pebble conglomerates. In the Arthur Creek Formation the genus occurs in anaerobic calcimuds tone deposited in a low-energy shelf area of limited circulation. Jawo nya and Wagima are elements of a sponge-mollusc association in open sh elf onkoid limestones of the Tindall Limestone. Rankenella is among th e oldest known intact demosponges. Spiculation in Jawonya and Wagima s uggests that the history of the heteractinide astraeospongiid-wewokell id lineage was one of Ordovician reduction or loss of original polyact ines in favour of octactines, followed by polyactine reinstatement in the Carboniferous.