Seed plant diversity in the Triassic of Antarctica: A new anatomically preserved ovule from the Fremouw Formation

A new anatomically preserved ovule is described from the Middle Triassic Fremouw Formation of the Beardmore Glacier area, Antarctica. Probolosperma antarcticum gen. et sp. nov. is bilaterally symmetrical and up to 1 cm long and 6 mm wide. The integument is characterized by a complex sarcotesta with a palisade-like outer layer and a sclerotesta that forms two small lateral wings and elaborations in the chalazal and apical regions. The vascular system consists of a terete strand that enters the pedicel to form a small cup of tracheids at the base of the nucellus, with two strands that extend distally in the inner part of the sclerotesta. Comparisons with other gymnosperm ovules indicate that Probolosperma represents a new taxon, which enhances the diversity of known seed plants from the Triassic of Antarctica.