Abstract Detail



Paleobotany

Jud, Nathan [1], Rothwell, Gar [2], Stockey, Ruth [3], Beard, Graham  [4].

New details on the diversity of a Late Cretaceous flora from Hornby Island, British Columbia, Canada.  .

Angiosperm woods provide enlightening information about the evolution and geographical expansion of angiosperm-dominated ecosystems throughout the Cretaceous and Paleogene. Anatomically preserved plant fossils in the Upper Cretaceous rocks of the Northumberland Formation at Collishaw Point, on the northeastern tip of Hornby Island, British Columbia include abundant fossil woods. The assemblage includes both gymnosperm woods (e.g. Cunninghamia hornbyensis, Cupressaceae) and angiosperm woods (e.g. Atli morinii, Ranunculales) that have been described to date. Many of the fossil stems include well-preserved pith, wood, and bark tissues. We prepared stem segments using the cellulose acetate peel technique and examined them under light microscopy. A preliminary analysis of a collection that includes more than 60 specimens indicates that the angiosperms are especially species-rich; however, very few are from stems >10 cm in diameter. We estimate at least 18 species of dicots (non-monocot angiosperms), 3 species of monocots, and 4 species of gymnosperms. Our examination of the dicots in transverse section revealed that 17/18 are diffuse porous, 9/18 have exclusively solitary vessels, (including tangential pairs) and 17/18 have axial parenchyma diffuse or diffuse-in-aggregates. These patterns are typical of Cretaceous angiosperm woods from the Northern Hemisphere, but unusual for modern floras. Among the newly recognized taxa are a platanoid (Platanaceae) and an icacinoid (cf. Dilleniaceae). We compare these specimens with living and fossil taxa, and explore similarities of the systematic composition with the similarly rich, coeval assemblage of fossil woods from the Upper Cretaceous Panoche Formation of central California.


1 - William Jewell College, Biology, 300 College Hill, Liberty, MO, 64068, United States
2 - Oregon State University, Department Of Botany And Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331, United States
3 - Oregon State University, Department Of Botany And Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331.0, United States
4 - Vancouver Island Palaeontological Museum, Qualicum Beach, BC, Canada

Keywords:
anatomy
Platanaceae
fossil wood
Campanian.

Presentation Type: Oral Paper
Number: 0003
Abstract ID:442
Candidate for Awards:None


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