Abstract Detail

Paleobotany

Posey, Nyshele [1], Ryberg, Patricia Elizabeth [2].

New Late Permian permineralized glossopterid ovules from the Nimrod Glacier region, Antarctica.

During the Permian age, (252–299 Ma), Gondwana was covered with the seed fern group Glossopteridales. Most glossopterid fossils are found as impressions, which limits and confounds interpreting three dimensional structures such as reproductive organs. Permineralized material, although rare, can provide detailed anatomical information about a fossil plant as the cellular structure is preserved. In this study a permineralized groups of ovules from Turbidite Hill in the Nimrod Glacier (82°1’ S 157° 45’E) region of Antarctica are described. The specimen belongs to the Late Permian Buckley Formation which has been reconstructed as a braided river depositional environment. More than seven ovules are clustered together and appear attached to a single structure. The ovules measured 2.77 mm in length and 1.29 mm in width. The sacrotesta is 85–213 μm thick with thin walled cells full of dark contents. A distinctive feature of the surface of the ovules is the presence of small spines that cover the surface. The sclerotesta is 109–164 μm thick and consists of isodiameteric cells with thick walls with scalariform thickenings and measure 14–42 μm in diameter. The endotesta is not easily observed, but the nucellus appears to be broadly attached at the base of the integument and free for the rest of the length. When comparing these ovules to other permineralized ovules from Antarctica, they are most similar to the genus Choanostoma. The sarcotesta of both ovule types have small spines, and the sclerotesta have highly sclerified cells. However, the shape of the ovules differs as the length of Choanostoma includes distinctive sarcotestal pads which overarch the micropyle whereas these new ovules have no distinctive micropylar end. To date, all permineralized ovules from Antarctica have been from the Skaar Ridge locality in the Beardmore Glacier region. This new genus of ovule presents data from a different position of the same braided river system as Skaar Ridge and may provide a hint of the broader diversity of Antarctic glossopterids.

1 - Park University, Department of Natural & Physical Sciences, Parkville, MO, 64152, USA
2 - Park University, Department of Natural & Physical Sciences, 8700 NW River Park Drive, Parkville, MO, 64152, USA

Keywords:
Permian
glossopterids
ovule
Antarctica.

Presentation Type: Oral Paper
Session: 12, Cookson/Moseley award presentations
Location: Sundance 4/Omni Hotel
Date: Monday, June 26th, 2017
Time: 2:30 PM
Number: 12005
Abstract ID:279
Candidate for Awards:Isabel Cookson Award