Chitinozoans from seven cores in the Middle Ordovician upper Goldwyer and Nita formations are documented, and three assemblages are delineated. Six out of twelve species found in the Canning Basin, in eastern Gondwana, are also found in Laurentia, confirming the close relationship between chitinozoans in the two palaeocontinents. The assemblages correlate with Zone 05 of Combaz & Peniguel, and the undefined zone immediately overlying the Cyathochitina jenkinsi Zone in the biozonation designed for Laurentia. The relationship between contemporaneous assemblages in Baltica, Avalonia and the northern Gondwana Domain is discussed with a small number of species in common with Baltica and Avalonia, and no definite links with northern Gondwana. Two new species Calpichitina windjana, and Belonechitina vibrissa are described.

Key words: Middle Ordovician, Darriwilian, Chitinozoans, Canning Basin, biozonation, Australia.

Theresa Winchester-Seeto [twinches@laurel.ocs.mq.edu.au], Centre for Ecostratigraphy and Palaeobiology, Department of Earth and Planetary Sciences, Macquarie University, 2109. Australia;Clinton Foster [clinton.foster@agso.gov.au], Australian Geological Survey Organisation, GPO Box 378 Canberra, 2601. Australia;Teresa O'Leary [teresa.oleary@utas.edu.au], IASOS, University of Tasmania, PO Box 252c, Hobart, 7001. Australia.