In this Letter, the Methods section ‘TEM’ should read “Isolated microfossils were embedded in agar-agar gelose and dehydrated in a graded ethanol series, then infiltrated successively in 1,2-propylene oxide, 1:1 propylene oxide/epoxy resin melange and then in pure epoxy resin. The samples were placed in silicon moulds and left to polymerize at 60 °C for 3 days. The resin blocks were cut into ultrathin (60–100 nm) transversal sections with a diamond knife on an ultramicrotome Reichert Ultracut. Sections were put on formvar-coated copper grids and imaged at an accelerating voltage of 200 kV with a transmission electron microscope Tecnai G² Twin (CAREM, University of Liège).” instead of “Isolated microfossils were embedded in agar, dehydrated in a series of ethanol solutions and then infiltrated successively with propylene oxide and ethanol, propylene oxide and epoxy resin, and pure epoxy resin. Samples were polymerized in an oven at 60 °C for at least 12 h. The resin blocks were cut into 1-mm-thick (semi-thin) and 50-nm-thick (ultra-thin) sections with a diamond knife. Sections were put on copper grid with Formvar, and imaged at 80 keV with a transmission electron microscope JEM100SX.”