Hi all, Does anyone have any idea what this could be? I found them at the SEM in samples from the middle Eocene (Lutetian) of Austral Basin (Argentina). It seems that it is not birefringent as I didn't see them at the OM. Cheers, Juan Dr. Juan Pablo Pérez Panera CONICET División Paleozoología Invertebrados, Museo de La Plata, FCNyM, UNLP Paseo del Bosque s/n, 1900, La Plata Buenos Aires, Argentina perezpanera at gmail.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://webmail.fcnym.unlp.edu.ar/pipermail/coccoliths/attachments/20210301/418b12b1/attachment.htm> -------------- next part -------------- A non-text attachment was scrubbed... Name: R. dictyoda.tif Type: image/tiff Size: 13481904 bytes Desc: not available URL: <http://webmail.fcnym.unlp.edu.ar/pipermail/coccoliths/attachments/20210301/418b12b1/attachment.tif> -------------- next part -------------- A non-text attachment was scrubbed... Name: 7.tif Type: image/tiff Size: 3941874 bytes Desc: not available URL: <http://webmail.fcnym.unlp.edu.ar/pipermail/coccoliths/attachments/20210301/418b12b1/attachment-0001.tif>