Middle Jurassic (Bajocian) planktonic foraminifera from the northwest Australian margin

• Published in: Journal of Micropalaeontology
• Main Author: M. Apthorpe
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2020
• Subjects: Geology; QE1-996.5; Planktonic foraminifera
• Online Access: https://doi.org/10.5194/jm-39-93-2020; https://doaj.org/article/37eb47f08eac47c4b9ced7bde5cf599a

The aim of this paper is to document three well-preserved morphotypes of Middle Jurassic (Bajocian) planktonic foraminifera from the continental margin of northwestern Australia. This location is on the southern shelf of the Middle Jurassic Tethys Ocean, and these occurrences of planktonic or meroplanktonic species are the first to be reported from the Jurassic of the Southern Hemisphere. The morphotypes include a new subspecies of Globuligerina bathoniana (Pazdrowa): Globuligerina bathoniana australiana n. ssp. Two other taxa are also described: Globuligerina altissapertura n. sp. and Mermaidogerina loopae n. gen. n. sp. The microstructure of the wall is shown in scanning electron microscope images. The change from chamber to chamber in the formation of the surface ornament by secondary lamination, and its subsequent burial within the wall, is demonstrated in detail.