Chitinozoa from Lower Ordovician strata of the Georgina Basin, Queensland (Australia)

A chitinozoan fauna is reported from a shallow-marine Lower Ordovician sequence in the subsurface of the southeastern Georgina Basin, Queensland (Australia). From the sampled corehole (GSQ Mount Whelan 2), material of the upper Kelly Creek Formation proved barren of chitinozoans, but samples representative of the overlying Coolibah and lower Nora Formations yielded generally well-preserved, compressed specimens. The upper Coolibah and Nora samples proved especially prolific, though as a whole the chitinozoan assemblage is of fairly low diversity (seven species/three genera recognizable). One new species, Belonechitina noraensis, is formally established. The morphological simplicity of the chitinozoans compares closely with those described from approximately age equivalent strata of Quebec and Spitsbergen but contrasts with more complexly structured forms characteristic of European and North African deposits. The presence of such species as Conochitina ordinaria Achab, C. pervulgata (Umnova), and Lagenochitina combazi Finger are consonant with the late Early Ordovician (Arenigian) dating of the host strata as adduced previously on other palaeozoological grounds.