Abstract Detail

Fossil plants at the intersection of evo-devo and phylogeny: celebrating the contributions of Gar W. Rothwell to biodiversity and evolution

Bippus, Alexander [1], Rothwell, Gar [2], Stockey, Ruth [3], Tomescu, Alexandru M.F. [4].

Early Cretaceous bryophyte biogeography? Insights from the west coast of North America.

The Early Cretaceous (Valanginian, 136 Ma) Apple Bay flora of Vancouver Island, Canada, has emerged as a hotspot of permineralized bryophyte diversity. Recently, exploration of the Budden Canyon Formation of California (Barremian-early Aptian, 125 Ma), characterized by similar taphonomy and mode of preservation to Apple Bay, has revealed another rich bryophyte flora. The anatomically preserved material at Apple Bay has provided excellent insights for resolving the taxonomic affinities of these fossils, even for specimens represented by a single gametophyte shoot. This emphasizes the potential that permineralized bryophyte fossils have to enrich our understanding of bryophyte evolution. Thus far, a wide variety of cryptogam gametophyte fossils have been discovered at Apple Bay including acrocarpous mosses (Polytrichaceae, Grimmiaceae, Leucobryaceae), the oldest unequivocal pleurocarpous mosses (Tricostaceae), and thalloid gametophytes comparable to liverworts and filicalean fern gametophytes. Surveys of the Budden Canyon Formation have revealed a remarkably similar set of taxa including acrocarpous mosses (Polytrichaceae, Leucobryaceae), pleurocarpous mosses (Tricostaceae), and thalloid gametophytes similar to liverworts and fern gametophytes. The Budden Canyon and Apple Bay floras are similar in many ways. They are both allochthonous near-shore marine plant fossil assemblages representing coastal conifer-dominated plant communities, with significant fern and bryophyte diversity. These localities are temporally separated by only 10-15 million years and spatially by less than 1,000 miles. This parallelism allows for consideration of these fossil assemblages in terms of biogeographic patterns for bryophytes. Since the two localities represent roughly coeval and similar plant communities, with similar taphonomic histories, we can query the similarity of their bryophyte communities. Although we have yet to characterize the Budden Canyon bryoflora in detail, and work is not finished at Apple Bay, the two localities seem to harbor broadly similar bryophyte communities. While these results are to be expected, given the close parallels between the two localities, the ability to make broad biogeographic comparisons of bryophyte floras is not something that could have been imagined outside of amber deposits such as the Baltic and Bitterfeld amber, up until now. Studies of the Apple Bay and Budden Canyon floras demonstrate that we can now start thinking in terms of broad biogeographic patterns, critical for understanding the bigger picture of bryophyte evolution, as far down in time as the Cretaceous and in other modes of preservation besides amber.

1 - Humboldt State University, 112 H Street, Arcata, CALIFORNIA, 95521, 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 - Humboldt State University, Department Of Biological Sciences, 1 Harpst Street, Arcata, CA, 95521, United States

Keywords:
fossil
Bryophytes
Biogeography
mosses
liverworts
gametophytes
permineralized
Cretaceous.

Presentation Type: Colloquium Presentations
Session: C11a, Fossil plants at the intersection of evo-devo and phylogeny: celebrating the contributions of Gar W. Rothwell to biodiverstiy and evolution Part 1
Location: 110/Mayo Civic Center
Date: Wednesday, July 25th, 2018
Time: 10:30 AM
Number: C11a008
Abstract ID:706
Candidate for Awards:None