Abstract Detail

Paleobotanical Section

Parsley, Kathryn [1], Dunn, Michael [2].

The Reproductive Biology of Winslowia tuscumbiana, a Cormose Ligulate Lycopsid in the Serphukovian of Alabama.

In a recent paper Dunn et al. 2012 reconstructed the whole ligulate, cormose-based, heterosporous, lycopsid plant Winslowia tuscumbiana, except for the microsporophylls and microspores. Winslowia was recovered in a Serphukovian salt marsh assemblage in a limestone quarry in Tuscumbia, Alabama. The strata where Winslowia was found consisted of siltstone over burden (of the limestone), and was randomized by the mining process into spoils piles where Winslowia was the only plant recovered. Because Winslowia organs were the only plant fossils recovered, the assemblage was assumed to be monospecific. Therefore, the major component of the microspore flora of the strata should be the microspore produced by Winslowia. Since Winslowia is a Mississippian lycopsid,we hypothesized that the microspore should be the spore genus Lycospora. Ten palynology samples were processed into 24mm by 50mm strew slides and on one of the slides all of the microspores were counted and identified. Analysis of the other nine were by transect. However, our hypothesis was not supported. The first slide contained 6248 spores and Lycospora only comprised a plurality at 34.8% with Cyclogranisporites at 29.7% and Granulatisporites at 19.1%. Twenty-four additional spore genera were identified, but together only comprised 16.4% of the sample. Therefore, our hypothesis must be revised and we are considering three possible alternative hypotheses. One alternative hypothesis would be that Winslowia was not heterosporous, but rather homosporous. However, that would imply that the conventional wisdom suggesting that the over 400µm in diameter, triletes-type spores are megaspores is incorrect, and that, at least in part, some of these are isospores. A second alternative hypothesis would be that Winslowia might be dioecious with microspore producing plants spatially separated and a third possibility would be that the production of microspores and megaspores is temporally segregated.

1 - Cameron University, Biological Sciences, 2800 Gore, Lawton, OK, 73505, USA
2 - Cameron University, 2800 Gore Blvd, Lawton, OK, 73505, USA

Keywords:
Cromose
Ligulate
Lycopsid
Serphukovian
Winslowia.

Presentation Type: Oral Paper:Papers for Sections
Session: 1
Location: Salon 5/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 8:45 AM
Number: 1004
Abstract ID:671
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award