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Fossil assemblages preserved in nodules of the methane-seep deposits, recognized by Haig et al. (2022) in the lower Permian (Cisuralian, Sakmarian stage) of the Irwin Basin, include representatives of three ecosystems: seep, pelagic, and coastal plain. The seep biota, new to the Australian Permian, consists of small thickets with a framework of tubeworms, less common algal-like Tubiphytes, and problematica (? algae or sponges). Other components include microbial mats, macrophyte alga Litostroma (first report from Gondwana); foraminifers; sponges with siliceous monaxon spicules; a new group of small, lightly ornamented rostroconchs; microgastropods and rare larger types; ostracods and minute scolecodonts from polychaete jaws. Elements of the pelagic ecosystem are ammonoids (abundant in enclosing shale) and marine microphytoplankton. Probable vertebrate bone (possibly amphibians) and diverse …