Pollen morphology of Tetraglochin (Sanguisorbeae): A contribution to the understanding of the fossil record of Rosaceae

The present study describes and illustrates for the first time the pollen morphology of the six species of genus Tetraglochin (Rosaceae, Sanguisorbeae) using light microscopy (LM). T. acanthocarpa, T. alata, T. andina, T. caespitosa, T. cristata and T. inermis were compared with the pollen fossil record with rosaceous affinity. The fossil form that presents a greater similarity with the species studied is Psilatricolporites quenua (Río Leona Formation, Late Oligocene, Santa Cruz, Argentina). P. quenua presents a marked similarity with Tetraglochin in all measured characters and in its ornamentation. Previous paleobiogeographic interpretations were evaluated considering the new data provided in this contribution. •The pollen morphology of genus Tetraglochin is described and illustrated for the first time.•Species from Southernmost Patagonia have pontoperculum.•The most similar fossil form is a record from the Late Oligocene of Patagonia.•The origin of the genus could be older than previously proposed.