TAYLOR, EDITH L., THOMAS N. TAYLOR*, RUBÉN CÚNEO, ANA ARCHANGELSKY, AND HANS KERP. Department of Botany and Natural History Museum-Biodiversity Research Center, University of Kansas, Lawrence, KS 66045-2106, USA; Museo Paleontológico Egidio Feruglio, 9100 Trelew (Chubut), Argentina; Abteilung Paläobotanik, Westfälische Wilhelms Universität Münster, D-48183, Münster, Germany. - Cupulate reproductive organs from the Triassic of the Shackleton Glacier area, Antarctica.
Diverse floral remains were collected from a site near the Shackleton
Glacier, Antarctica during the 1995-1996 austral field season. The
locality includes small accumulations of permineralized peat, in
situ trunks, and impression/compression fossils, all within a
series of fluvial deposits. The compression flora is dominated by the
corystosperm leaf type Dicroidium, but leaves assignable to
Heidiphyllum are also present. Fossils occur in the upper
Fremouw Formation or the overlying Falla Formation and are believed to
be late Middle to early Late Triassic in age. A number of specimens
of compressed reproductive organs were also discovered. Many of these
correspond to the cupulate corystosperm taxon Umkomasia, but
some exhibit a different morphology. At least one of the latter type
is preserved still attached to a vegetative branch. This specimen
consists of a main axis about 1.5 cm in diameter, bearing stout,
alternately arranged lateral axes up to 3 cm long that look like short
shoots. On the surface of the laterals are closely-spaced lenticular
scars that appear to represent the former positions of leaves.
Attached to the tip of some of these short shoots are elongate,
slender axes, each terminated by a cupule-like structure. The cupule
is flattened and appears to consist of several units that may
represent either cupule lobes or seeds. The affinities of these
reproductive organs will be discussed as they relate to the vegetative
remains at the site, and to other Mesozoic cupulate organs.
Key words: Antarctica, cupules, ovulate, pteridosperm, reproductive, Triassic