Symbionts in a stromatoporoid-chaetetid association from the Middle Devonian Burdekin Basin, north Queensland

Abstract

A spectacular association between a chaetetid, a stromatoporoid (Salairella sp.), and straight, vertical tubes interpreted to have housed symbiotic worms is reported from the Givetian Burdekin Formation, Burdekin Basin, north Queensland. The final growth surface of Salairella sp. shows skeletal distortion characterised by long, rather continuous coenosteles and coenostroms with upturned edges. This distorted interface was probably the result of spatial competitive interaction between the encrusting chaetetid and the underlying stromatoporoid. Neither sediment infilling, erosion or surface breakage occurs on the final growth surface of the stromatoporoid skeleton. As such, the growth of the Salairella sp. specimen appears to have been supressed by the encrusting chaetetid. Worm tubes are continuous through the distorted interface without interruption. The skeletal association also suggests that the round, straight, vertical tubes had a symbiotic intergrowth relationship initially with the stromatoporoid and, subsequently, the chaetetid.