Abstract Detail



Paleobotany

Stockey, Ruth [1], Rothwell, Gar [2], Atkinson, Brian [3].

Late Cretaceous diversification of cupressaceous conifers; a taiwanioid seed cone from the Eden Main, Vancouver Island, British Columbia, Canada.

A single cylindrical conifer seed cone is preserved in a calcium carbonate marine concretion from the Eden Main quarry, near Comox on Vancouver Island, British Columbia, Canada. The specimen comes from the Upper Cretaceous Comox Formation of the Nanaimo Group, dated as early Coniacian (~89 Ma). The cone is somewhat abraded, at least 2.3 cm long and 1 cm wide, with the apex missing and most of the base coalified. The well-preserved mid-section, however, shows cone scale complexes inserted at a steep angle. The cone scale complex has a central rhomboidal shaft and two lateral wing-like extensions. The pith of the cone axis is composed of elongate parenchymatous cells with dark contents. Xylem of the cone axis is robust, with scalariform primary xylem elements and uniseriate circular-bordered pits on the radial walls of secondary xylem tracheids. Vascular rays are uniseriate and only a few cells high; and no resin canals have been observed in the wood. A single circular vascular trace enters the bract/scale complex and divides near the adaxial surface to form several bundles. There are three resin canals/scale that divide to form five, and up to nine distally. On the adaxial surface of the scale the cells beneath the epidermis show a convoluted shape. Up to six overlapping winged seeds, ~ 8 mm long and 1 mm thick, with two fleshy wings are borne on each scale. Cells of the seed epidermis are conspicuously large. The nucellus is attached to the endotesta most of the way up (at least half-way). Megagametophytes and embryos occur in some seeds. Cells of the megagametophyte have granular contents. This cone shows similarities in vasculature and cone structure to those of Taiwania (Cupressaceae), however the seeds with conspicuously large, fleshy folded wings are the most prominent component of the cone.


1 - Oregon State University, Department Of Botany And Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331.0, United States
2 - Ohio University/Orgon State Universtiy, Environmental and Plant Biology, Department of Environmental and Plant Biology, 318 Porter Hall, Athens, Ohio, 45701, USA
3 - University of Kansas, Department of Ecology and Evolutionary Biology, 6012 Haworth Hall, Lawrence, KS, 66044, USA

Keywords:
Cupressaceae
taiwanioid
Late Cretaceous
seed cone.

Presentation Type: Oral Paper
Session: 24, Late Mesozoic and Cenozoic Paleobotany
Location: 109/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 10:15 AM
Number: 24001
Abstract ID:150
Candidate for Awards:None


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