Three well-preserved new species of Middle Jurassic (Bajocian) planktonic foraminifera from the continental margin of northwest Australia are described. This is on the southern shelf of the Tethys Ocean, and these planktonics are the first to be reported from the Jurassic Southern Hemisphere. Described as new are Globuligerina bathoniana australiana n. ssp., G. altissapertura n. sp. and Mermaidogerina loopae n. gen. n. sp. The research is part of a study of regional Jurassic foraminifera.

We identify the first continuous carbonate-bearing sediment record from the tropical ocean that spans the entirety of the global warming event, the Middle Eocene Climatic Optimum, ca. 40 Ma. We determine significant mismatches between middle Eocene calcareous microfossil datums from the tropical Pacific Ocean and established low-latitude zonation schemes. We highlight the potential of ODP Site 865 for future investigations into environmental and biotic changes throughout the early Paleogene.

We described two new species of the fossil dinoflagellate cyst genus Svalbardella. S. clausii sp. nov. has a narrow range in the lowermost Chattian and may be related to cooler surface waters. S. kareniae sp. nov. ranges from Lower Oligocene to Lower Miocene and favours more open marine conditions. Our study illustrates the close phylogenetic relationship between Svalbardella and Palaeocystodinium and shows that surface ornamentation and the tabulation are variable features within both genera.