1 Stomatal pore length change in leaves of Eotrigonobalanus furcinervis (Fagaceae) from the 1 Late Eocene to the Latest Oligocene and its impact on gas exchange and CO 2 reconstruction 2 Anita Roth‐Nebelsick a *, Michaela Grein a , Torsten Utescher b , Wilfried Konrad c 3 a State Museum of Natural History Stuttgart, Rosenstein 1. D‐70191 Stuttgart, Germany 4 b Steinmann Institute, Bonn University, Nußallee 8 , 53115 Bonn, Germany 5 c Institute for Geosciences, University of Tübingen, Sigwartstr. 10, D‐72076 Tübingen, Germany 6 *Corresponding author 7 Anita Roth‐Nebelsick: 8 anita.rothnebelsick@smns‐bw.de 9 Phone: ++49(0)711 8936 148 10 Fax: ++49(0)711 8936 100 11 Michaela Grein: 12 michaela.grein@smns‐bw.de 13 Phone: ++49(0)711 8936 179 14 Fax: ++49(0)711 8936 100 15 Torsten Utescher: 16 utescher@geo.uni‐bonn.de 17 Phone: ++49 (0)228 73 97 73 18 Fax: ++49(0)228 73 90 37 19 Wilfried Konrad: 20 wilfried.konrad@uni‐tuebingen.de 21 Phone: ++49(0)7071 29 73561 22 23 24 http://www.sciencedirect.com/science/article/pii/S0034666712000024