Abstract Detail

Paleobotanical Section

Hieger, Timothy J. [1], Serbet, Rudolph [2], Harper, Carla J. [1], Taylor, Thomas N. [1], Taylor, Edith L. [1].

Anatomy of a coniferous pollen cone from Carapace Nunatak (Lower Jurassic), southern Victoria Land, Antarctica.

Permineralized deposits offer exceptional insight into the anatomy and morphology of ancient plants. Although Jurassic floras have been known for many years from the Antarctic Peninsula, Jurassic plants from continental Antarctica are very rare. Therefore, fossils from southern Victoria Land, Antarctica provide the opportunity to better understand the diversification and biogeographical distributions of Early Jurassic plants on the continent. Fossiliferous cherts collected from the Carapace Nunatak locality during several field seasons yield a variety of anatomically preserved plant remains. These include two coniferous pollen cones with affinities to the Cheirolepidiaceae that will be the focus of this contribution. Specimens were studied using the standard acetate peel technique, transmitted light microscopy, and SEM analysis. The cones are round to ovoid, up to 5 mm in length and 4 mm in diameter, and consist of peltate microsporophylls primarily comprised of transfusion tracheids; the distal lamina is rhomboidal. There are numerous pollen sacs per microsporophyll. Various levels of maturity and ontogenetic development are represented by these cones but perhaps the most interesting is an immature cone that contains over 100 pollen sacs full of pollen in various stages of development; grains occur predominately as tetrads. The in situ Classopollis pollen has spinulose supratectal elements, a reticulate infrastructure, distal cryptopore, subequatorial rimula, vague striae, and a proximal trilete. Grains are sub-spheroidal in shape and are 18–36 µm in diameter with an average diameter of 27 µm. These pollen cones along with other remains, e.g., ferns, coniferous stems and leaves, microorganisms, and arthropods, found within the Carapace Nunatak cherts provide an important piece of the puzzle in reconstructing the paleoenvironmental setting in which these conifers occurred. Overall, this study provides insight into the biology, evolutionary history, and paleobiogeographical distribution of ancient conifers.

1 - University Of Kansas, Ecology And Evolutionary Biology, 2041 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
2 - University Of Kansas, Division Of Paleobotany, Nat Hist Mus & Biodiv Res Inst, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
3 - University Of Kansas, Ecology And Evolutionary Biology, 2041 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA

Keywords:
Pollen cone
Conifers
Jurassic
Antarctica
Anatomy
morphology
fossil.

Presentation Type: Oral Paper:Papers for Sections
Session: 11
Location: Salon 5/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 10:15 AM
Number: 11001
Abstract ID:588
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award