Abstract Detail

Paleobotanical Section

Shelton, Glenn W.K. [1], STOCKEY , RUTH A [2], ROTHWELL , GAR W [3], Tomescu, Alexandru M.F. [4].

Bryosymbiotic fungi from the Early Cretaceous (Valanginian) of Vancouver Island, British Columbia, Canada.

The Early Cretaceous (ca. 136 Ma) fossil flora of Apple Bay, Vancouver Island is known for its gymnosperms, ferns, bryophytes, fungi and lichens preserved in marine carbonate nodules at Apple Bay.  This study reveals another facet of fungal diversity: bryosymbiotic fungi associated with a single tricostate moss species.  Nine morphologies ranging from ascomycetous fruiting bodies to moniliform chains are observed in organic connection with moss gametophyte tissues: (1) groups of few, round, thin-walled cells (4.0-8.0 µm) endophytic within leaf cells; (2) oblong clusters of closely appressed cells (ca. 4 x 10 cells; diameters 4.0-9.0 µm) dispersed around axils or adhering to laminae; (3) moniliform chains of up to 20 round cells (3.5-8.0 µm) with variable wall thickness, ornamentation, and color; epiphytic on all tissues; (4) aggregates of small (3.0-5.0 µm diameter), dark, thin-walled cells, adhered to laminae near axils; (5) epiphytic septate filaments (2.0-5.0 µm diameters) branched infrequently, and composed of light to dark thin-walled cells (lengths 7.0-9.0 µm); (6) dense bundles of hyphae (3.0-5.0 µm diameters) typically between laminae; (7) round to reniform (10.0 x 20.0µm) or irregularly-shaped spore-like structures with dark, thick, smooth walls, dispersed between leaves or in loose several-celled clusters; some exhibit a longitudinal slit to 10.0 µm long; (8) mycelial “sheets” 50-100 µm thick, stratified (dark outer layer) and composed of a heterogeneous mixture of loosely-interwoven hyphae (including moniliform filaments), engulfing basal portions of moss stems; (9) perithecioid fruiting bodies (ostiolate; spherical to subspherical; diameters 140-175 µm) embedded within shoot tips.  However, intergradation is observed between some of the morphologies, indicating that fewer than nine fungal taxa are present on the mosses.  The association of these fungi with a single moss species, recurring in multiple carbonate nodules, suggests a high degree of specificity, possibly linked to the anatomy and morphology of the moss - delicate leaves, extremely dense foliation (9-23 leaves/mm).  Several lines of evidence indicate that this association formed on living gametophytes: (1) recurring association with one moss species; (2) absence of the fungi from other fossils in the same concretions; (3) sorting of different fungal morphologies within specific positions on the gametophytes.  Ascomycetes are the main fungal group involved in bryophyte-fungal interactions and the features of the Apple Bay bryosymbionts suggest ascomycete affinities.  This is the first bryophyte-fungal interaction documented in the fossil record and adds a new array of diversity to the fungi previously described from the Early Cretaceous Apple Bay flora.

1 - Humboldt State University, Biological Sciences, 120A 13th Street, Arcata, CA, 95521, USA
2 - Oregon State University, Department of Botany and Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331, USA
3 - Oregon State University, Department Of Enviromnental & Plant Biology, 2082 Cordley Hall, Corvallis, OR, 97331, USA
4 - Humboldt State University, Department Of Biological Sciences, 1 Harpst Street, Arcata, CA, 95521, USA

Keywords:
Fossil
Cretaceous
bryosymbiotic
fungi
moss
bryophyte.

Presentation Type: Oral Paper:Papers for Sections
Session: 8
Location: Whitewater/Grove
Date: Monday, July 28th, 2014
Time: 11:00 AM
Number: 8010
Abstract ID:751
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award