A new early Cambrian bradoriid (Arthropoda) assemblage from the northern Flinders Ranges, South Australia

Abstract

A new assemblage of early Cambrian bivalved arthropods (Bradoriida) is described from the Arrowie Syncline in the northern Flinders Ranges, South Australia. The well preserved, largely endemic fauna comprises a total of six taxa (including five new species): 'Jiucunella phaseloa' sp. nov., 'Jixinlingella daimonikoa' sp. nov., 'Mongolitubulus anthelios' sp. nov., 'Neokunmingella moroensis' sp. nov., 'Phasoia cf. spicata' (Öpik, 1968), and 'Sinskolutella cuspidata' sp. nov. This assemblage is derived from a carbonate sedimentary package representing a high energy, shallow water archaeocyath-Renalcis biohermal facies of Terreneuvian, Stage 2 age which transitions up-section to a more restricted, low energy, intra-shelf lagoonal environment that correlates with a Cambrian Series 2, Stage 3 age. The new taxon 'J. phaseloa' sp. nov., has a first appearance datum (FAD) in shallow water biohermal facies of the Hideaway Well Member of the Wilkawillina Limestone at a level 47 m below the FAD of 'Pelagiella subangulata' which is taken to approximate the base of Series 2, Stage 3 in South Australia. Along with 'Liangshanella circumbolina', this makes 'J. phaseloa' sp. nov. amongst the oldest bivalved arthropods in South Australia and potentially greater Gondwana. The presence of 25 bradoriid taxa from the early Cambrian of South Australia suggests East Gondwana represents a major centre of origin for the Bradoriida.