Abstract Detail

Paleobotanical Section

Klymiuk, Ashley [1], Stockey, Ruth [2], Rothwell, Gar [2].

A taxodioid (Cupressaceae) seed cone from the Upper Cretaceous of British Columbia, Canada.

A single anatomically preserved seed cone was recovered from the Eden Main locality (Vancouver Island), a Coniacian succession of marine sandstones with phytodetrital remains preserved in CaCO₃ concretions. The elliptical cone measures 25 mm long and 7 mm wide, and has helically arranged bract/scale complexes which are almost entirely fused. The axis contains a narrow parenchymatous pith, surrounded by a slightly dissected vascular cylinder. The parenchymatous cortex contains 11-13 large resin canals. In transverse section, there appears to be an abscission layer where bract/scale complexes attach to the axis. The cylindrical vascular trace to the bract/scale complex is 100 μm in diameter, and is accompanied by one resin canal, 170-200 μm wide, which runs the entire length of the bract. The bract extends at a right angle from the cone axis for 2 mm, before narrowing and angling apically for a further 3.8 mm. Within the inflated portion of the bract, the resin canal ramifies laterally, producing 4-8 additional canals. These canals are smaller in diameter, and do not continue into the distal portion of the bract, which is sclerotic and triangular in cross section. The adaxial surface of the bract/scale complex bears three inverted winged ovules, 600 μm long and 375-550 μm wide, some of which contain megagametophyte tissue. Seeds are vascularized at their chalazal ends, and borne upon a parenchymatous pad. This parenchymatous tissue is arranged in periclinal files and is laterally continuous with a similar abaxial zone, which abruptly transitions to a sclerotic hypodermis near the outer margin of the cone. The small ovuliferous scale seen distal to the seed is 0.6 mm long, free from the bract at its tip, and densely sclerotic. Of the basal taxodioid members of the Cupressaceae, this new cone is most similar to the Jurassic Hughmillerites juddii (Seward et Bancroft) Rothwell, Stockey, Mapes et Hilton, but shows a suite of characters that place it in a new taxon.

Broader Impacts:

1 - University Of Alberta, Biological Sciences, CW 312 Biological Sciences Building, 116th And Sask. Drive, Edmonton, AB, T6G 2E9, Canada
2 - Oregon State University, Department of Botany and Plant Pathology, Corvallis, OR, 97331, USA

Keywords:
Cupressaceae
conifer
seed cone
Upper Cretaceous
conifer evolution
Hughmillerites juddii.

Presentation Type: Oral Paper:Papers for Sections
Session: 10
Location: Lindell C/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 11:15 AM
Number: 10004
Abstract ID:530