Charophyte gyrogonites and key gastropods and bivalves from the butte Iouton limestones. A–B: SEM photographs of characean gyrogonites from the lowermost characean-rich microbial laminites. A) Gyrogona caelata (Reid and Groves, 1921), lateral view. B) Gyrogona aff. lemani capitata (Grambast and Grambast-Fessard, 1981) lateral view. C–K: Common molluscan taxa. C) Lymnea Ioutensis (Roman, 1910). D) Planorbis stenocyclotus (Fontannes, 1884). E) Brotia Albigensis (Noulet, 1854). F) Tarebia barjacensis (Fontannes, 1884). G) Melanopsis acrolepta (Fontannes, 1884). H) Hydrobia celasensis (Fontannes, 1884). I) Assiminea nicolasi (Roman, 1910). J) Nystia plicata (d’Archiac and de Verneuil, 1845). K) Polymesoda dumasi (de Serres, 1827). Scale bar is 5 mm.