Rare, but not unique: a new specimen of the enigmatic gecko Rhodanogekko vireti from the lower Oligocene of southern Germany

Rhodanogekko vireti is one of the least known extinct geckos. It was described based on an isolated frontal from the middle Eocene of France, which until now includes the only material assigned to this species. In this contribution, we report an additional isolated frontal, coming from the lower Oligocene of southern Germany, which can be attributed to R. vireti based on a strong middle constriction and a dorsal rugose sculpturing. The new fossil extends the stratigraphic record of the species by about 10 Myr, and it is the first evidence for its presence outside France. The phylogenetic position of Rhodanogekko is still uncertain, but affinities with Sphaerodactylidae were suggested previously. If this is correct, the new frontal from Germany would fit into a stratigraphic gap without recorded confident sphaerodactylids in Europe, spanning the entire Oligocene. However, Rhodanogekko lacks the posterodorsal depressions or grooves apomorphic for frontals of Euleptinae, the subfamily including all European sphaerodactylids, extant and extinct. Additional fossils are needed to understand the relationships between Rhodanogekko and other gekkotans, and we here highlight the potential borne by the late Paleogene fossil record from southern Germany for new discoveries of these reptiles.