LAUSR

A biostratigraphically similar section to the GSSP of Fuentelsaz (Guadalajara, Spain) has been identified and proposed as an alternative section where paleontologists could, with permission of the Administration, conduct both scientific studies and didactic activities on the Toarcian-Aalenian boundary (Lower-Middle Jurassic) without compromising the integrity of the stratotype. This contribution reinforces the aforementioned proposal providing more detailed fossil data and biozone characterization from the lower interval of this limit. A new sampling at the section of Fuente del Molino (Guadalajara, Spain) adds new ammonoid taxa, which provides a more accurate definition of the zones and subzones limits of the Lower-Middle Jurassic. In addition, the finding of Leioceras opalinum between these new taxa allows locating the Toarcian-Aalenian limit in the section, thus bolstering its stratigraphic value. This contribution also promotes the didactic and divulgative potential of the Fuente del Molino section, raising awareness of both the geological and the palaeontological heritage of these sections.