This table contains Mean Annual Temperatures (MAT) reconstructed using branched GDGTs obtained on core FB2001 from Messel (earliest Middle Eocene; 47.66 to 47.22 Ma), relative to the core depth and age. The error given reflects the calibration error. Samples from the depth interval 17.38 to 30.88 m were analyzed in Frankfurt by high-performance liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry (HPLC-APCI-MS) on a Shimadzu UFLC device coupled to an AB Sciex 3200QTrap. Samples from the interval between 35.94 to 70.94 m core analyzed at RWTH Aachen University, Aachen (Germany), using an Agilent 1260 Infinity II HPLC coupled to an Agilent LC/MSD XT mass spectrometer.