Ordovician (Early Darriwilian) conodonts and sponges from west of Parkes, central New South Wales
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Abstract
A well preserved conodont fauna and an associated small sponge assemblage recovered from a limestone lens exposed on Kirkup Station, 15 km west of Parkes, New South Wales are described and illustrated. The conodont fauna is exceptionally rich by Australian standards, represented by nearly 4,000 specimens, but low in diversity including only six species: Erraticodon balticus Dzik, 1978, Kirkupodus tricostatus gen. et sp. nov., Protopanderodus cf. varicostatus (Sweet and Bergström, 1962), Protopanderodus? nogamii (Lee, 1975), Juanognathus serpaglii Stouge, 1984, and Pseudooneotodus mitratus (Moskalenko, 1973). The species definition of E. balticus is revised based on the current collection of some 1,700 specimens. Co-occurrence of E. balticus, J. serpaglii and P. cf. varicostatus suggests an early Darriwilian (Da2) age for the fauna, which can be correlated with the conodont fauna from the basal Weemalla Formation exposed further east near Orange. A shallow-water, near-shore setting for the fauna is also supported by the abundant occurrence of algal oncolites and certain sedimentary features in the limestone lens. Two anthaspidellid sponges occur in the assemblage. The stromatoporoid Lanilamina kirkupensis gen. et sp. nov. is the oldest stromatoporoid reported from Australia, and among the oldest known.
