title: Exploring the fossil history of pleurocarpous mosses: Tricostaceae fam. nov. from the Cretaceous of Vancouver Island, Canada.
abstract: OBJECTIVE
  Mosses, very diverse in modern ecosystems, are currently underrepresented in the fossil record. For the pre-Cenozoic, fossil mosses are known almost exclusively from compression fossils, while anatomical preservation, which is much more taxonomically informative, is rare. The Lower Cretaceous of Vancouver Island (British Columbia, Canada) hosts a diverse anatomically preserved flora at Apple Bay. While the vascular plant component of the Apple Bay flora has received much attention, the numerous bryophytes identified at the locality have yet to be characterized.
  
  
  METHODS
  Fossil moss gametophytes in more than 20 carbonate concretions collected from the Apple Bay locality on Vancouver Island were studied in serial sections prepared using the cellulose acetate peel technique.
  
  
  RESULTS
  We describe Tricosta plicata gen. et sp. nov., a pleurocarpous moss with much-branched gametophytes, tricostate plicate leaves, rhizoid-bearing bases, and delicate gametangia (antheridia and archegonia) borne on specialized branches. A new family of hypnanaean mosses, Tricostaceae fam. nov., is recognized based on the novel combination of characters of T. plicata.
  
  
  CONCLUSIONS
  Tricosta plicata reveals pleurocarpous moss diversity unaccounted for in extant floras. This new moss adds the first bryophyte component to an already diverse assemblage of vascular plants described from the Early Cretaceous at Apple Bay and, as the oldest representative of the Hypnanae, provides a hard minimum age for the group (136 Ma).
authors.affiliation: Department of Biological Sciences, Humboldt State University, Arcata, California 95221 USA.
authors.forename: Glenn W K
authors.initials: GW
authors.lastname: Shelton
authors.affiliation: Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331 USA.
authors.forename: Ruth A
authors.initials: RA
authors.lastname: Stockey
authors.affiliation: Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331 USA Department of Environmental and Plant Biology, Ohio University, Athens, Ohio 45701 USA.
authors.forename: Gar W
authors.initials: GW
authors.lastname: Rothwell
authors.affiliation: Department of Biological Sciences, Humboldt State University, Arcata, California 95221 USA mihai@humboldt.edu.
authors.forename: Alexandru M F
authors.initials: AM
authors.lastname: Tomescu
mesh_terms: D005075:Biological Evolution; D001955:British Columbia; D044002:Bryophyta / Q000145:classification* / Q000166:cytology / Q000235:genetics; D005580:Fossils; D055993:Germ Cells, Plant / Q000145:classification / Q000166:cytology; D062312:Islands; D018515:Plant Leaves / Q000145:classification / Q000166:cytology / Q000235:genetics; D018520:Plant Shoots / Q000145:classification / Q000166:cytology / Q000235:genetics
keywords: Bryophyta; Cretaceous; Hypnanae; fossil; gametangia; moss; pleurocarpous; tricostate