| Abstract Detail
Paleobotany Ryberg, Patricia Elizabeth [1]. A Permineralized Ovulate Cone from the Fremouw Formation of the Transantarctic Mountains, Antarctica. The Middle Triassic of Antarctic was a period of expansive diversity after the Permian-Triassic mass extinction. Antarctic localities from across the Transantarctic Mountains indicate a diverse landscape that contained representatives of; lycopsids, ferns, seed ferns, cycads, ginkgoes, and conifers. The diversity of Antarctic conifers is known from isolated leaves, pollen cones, ovulate cones, and seeds. To date, two ovulate cones are known, Parasciadopitys and Telemachus, which have recently been suggested to be the same conifer group, but of different preservation types. The Middle Triassic Fremouw Peak locality of the central Transantarctic Mountains contains the most diverse assemblage of plant fossils of both impression/compression and permineralized specimens in Antarctica. The permineralized cone Parasciadopitys is know from this locality and in this study, a new smaller permineralized cone has recently been found. Bract/Scale complexes are helically arranged on an axis. The bract is tri-lobed, the middle lobe has an acuminate apex with the elongated tip measuring 1.3 mm long. The scale is parenchymatous with isodiametric sclerified cells three to five layers thick along the margins. A single vascular bundle with scalariform thickenings extends the entire length of the ovuliferous scale. Two to three ovules appear to be embedded within the ovuliferous scale. Ovules measure 2–3 mm in length and 0.8 mm in width at the widest point. The integument is approximately 70 μm thick and the nucellus is free for the majority of the ovule length. This ovulate cone contains features of both Parasciadopitys and species of Telemachus, but is much smaller than either genus indicating that it is possibly new species of this conifer group. The cone/scale complex of both genera are between one and three cm long while this new cone’s scales measure only 5.5 mm in length. The sclerified margins of the ovule scale are similar to those of Parasciadoptyis, but the elongate acuminate apex of the bract is more like Telemachus. Studies on Telemachus species indicate that there are a variable number of ovules of this conifer group from two to five. This permineralized cone from Fremouw Peak presents features of both of these genera and enhances the links between Parasciadopitys and Telemachus providing support that these are members of the same natural genus.
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1 - Park University, Natural and Physical Sciences, 8700 NW River Park Drive, Parkville, MO, 64152
Keywords:
Triassic
Antarctica
conifer
Seed cone.
Presentation Type: Oral Paper
Session: 23, Paleozoic and Mesozoic Paleobotany
Location: 102/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 9:15 AM
Number: 23005
Abstract ID:845
Candidate for Awards:None |
