Reinvestigation of the type specimen of Ginkgophyllum grasseti Saporta 1875 using Reflectance Transforming Imaging

Reflectance Transforming Imaging (RTI) produces photographs in which the angle of the light can be changed at will, allowing to investigate remotely minute details of the 3D structure of sub-planar objects. Here we apply this technique to the type specimen of Gingkophyllum grasseti, a vegetative shoot with putative ginkgophyte affinities from the early Permian of Lodève (France). Gingkophyllum grasseti, the type species of the corresponding genus, was originally described by Saporta in 1875 and has never been illustrated other than by drawings representing only portions of the shoot. Using RTI, we describe and illustrate the specimen and discuss some key features, such as the arrangement of the leaves on the shoot or the presence of abundant secretory structures. Through a historical account, we show how the lack of illustration led to confusions about the morphology of Ginkgophyllum and we discuss the importance of reinvestigating type specimens of Paleozoic ginkgophyte taxa in order t...