Gymnosperm reproductive organs from the Triassic of Antarctica

The permineralized corystosperm pollen organ Pteruchus fremouwensis nov. sp., conifer ovulate cone Parasciadopitys nov. gen. (P. partitus nov. sp. and P. cavitatus nov. sp.), and compressed conifer ovulate cone Telemachus elongatus are described from the Triassic of Antarctica. Pteruchus fremouwensis consists of a eustelic axis bearing numerous helically arranged microsporophylls, each terminating in a flattened head. Secretory cavities are present in the ground tissue of the axis, microsporophyll and pollen sac wall. The basal stalk of the microsporophyll is vascularized by a C-shaped strand that gives rise to a midvein and numerous lateral veins in the distal head. At least 38 pollen sacs are borne on the abaxial surface of the microsporophyll head, and each is sessile, elongated and uniloculate. Dehiscence is longitudinal along the inner surface. Pollen is bisaccate. The specimens represent the first structurally preserved pollen organ of the Pteruchus-type, and can be related to the associated corystosperm stem and leaf genera based on the presence of the unique secretory cavities. The morphology of Pteruchus and relationship of it with other Mesozoic and Paleozoic pollen organs are discussed.; Telemachus elongatus ovulate cone is up to 4.0 cm long and 4.0 cm wide, and contains helically arranged cone scales. Each cone scale consists of an elongated bract fused to a 5-lobed ovuliferous scale. Two or three reflexed ovules are borne on each scale. Cuticles are described.; Parasciadopitys ovulate cones are up to 3.4 cm long and 1.4 cm wide, and consist of a eustelic axis with numerous helically arranged cone scales. The bract is basally fused with a 5-lobed ovuliferous scale. The vasculature pattern in the cone scale is described. Three to five inverted ovules are borne on each scale. Each ovule is dorsiventrally flattened and laterally winged, with the integument consisting of three zones. Parasciadopitys is compared with seed cones of closely related fossil and extant conifers and is believed to have affinities with the Taxodiaceae. Parasciadopitys and Telemachus from the Triassic of Antarctica provide the first evidence of conifer reproductive axes which support the suggestion that conifers have distributed south to Antarctica during the early Mesozoic.