SPOROPHYTES AND GAMETOPHYTES OF DICRANACEAE FROM THE SANTONIAN (LATE CRETACEOUS) OF GEORGIA, USA

A new species (Campylopodium allonense) of the moss family Dicranaceae is described for fossil sporophyte capsules and associated gametophyt es from the late Santonian (Late Cretaceous) Buffalo Creek Member of t he Gaillard Formation in central Georgia, USA. The sporophyte capsules are most comparable to those of the living genus Campylopodium. Spora ngia are curved, cylindrical, and strumose, with an obliquely rostrate operculum, cucullate calyptra, and compound annulus. The peristome is haplolepidous with 16 dicranoid, apically bifid teeth that are vertic ally striate on the outer surface and asymmetrically trabeculate on th e inner surface. Spores are spherical, alete, and finely rugose, and t hus differ from the finely papillose spores of extant Campylopodium. A ssociated fossil gametophytes Ne consistent with the morphology of ext ant Campylopodium and have leaves with a broad sheathing base and a na rrow blade. Spores identical to those in the sporangium occur on the l eaf surfaces of one of the gametophyte specimens, providing circumstan tial evidence that both sporophyte and gametophyte belong to the same species. Inadequacies of the moss fossil record have led to contrastin g interpretations of the timing of evolutionary change in this lineage since the Paleozoic. Campylopodium allonense unequivocally provides t he earliest evidence of Dicranaceae in the fossil record. This materia l, along with other fossil mosses from this late Santonian locality, i ndicates the presence of modern families of mosses in the Cretaceous. In a phylogenetic contest, these fossils from two different subclasses imply that mosses were already diverse by the Late Cretaceous.