First record of Selaginella from Miocene amber

Among extant lycophytes, Selaginella (Selaginellaceae, spike mosses) is the most species-rich genus, with over 700 described species. The evolutionary history of this lycophyte genus dates back to the Carboniferous or even Devonian; however, amber-preserved Selaginella fossils were previously only described from mid-Cretaceous amber from Myanmar. Here, we report the first fossil from Miocene Dominican amber attributable to Selaginella based on macromorphological characters and compare the fossil morphology to extant species of the genus. Selaginella jorelisiae sp. nov. can be identified based on the presence of symmetric ovate dorsal trophophylls with scattered teeth or cilia at the margins and an aristate apex, and ventral elliptic trophophylls with an apiculate apex and rounded base, with cilia on the acroscopic proximal margin and teeth all along the rest of the margin. Fossil and subfossil Selaginella representatives from the Greater Antilles have been described based on middle Oligocene, Pleistocene, and Holocene microspores or megaspores. Selaginella jorelisiae fills a gap in the local fossil record as it represents the first evidence of Selaginellaceae from the Miocene of these islands. While the previously discovered rich cryptogamic diversity from Dominican amber is considered to represent epiphytic communities, S. jorelisiae was most likely a component of the herbaceous layer of these humid tropical forests.