title: New methods reveal oldest known fossil epiphyllous moss: Bryiidites utahensis gen. et sp. nov. (Bryidae).
abstract: OBJECTIVE
  Epiphyllous bryophytes are a highly characteristic feature of many humid tropical forest ecosystems. In contrast to the extensive fossil record for the leaves of their host plants, the record is virtually nonexistent for the epiphylls themselves, despite a fossil record for mosses that begins in the Middle Carboniferous Period, 330 million years ago.
  
  
  METHODS
  Epifluorescence optical microscopy, scanning electron microscopy, and atomic force microscopy were employed to investigate an intimate association between a newly discovered epiphyllous moss and a Lauraceae plant host from the middle Cretaceous.
  
  
  RESULTS
  We describe the oldest fossil specimen of an epiphyllous moss, Bryiidites utahensis gen. et sp. nov., identified from an individual specimen only 450 µm long, situated on an approximately one millimeter square fossil leaf fragment. The moss epiphyll is exquisitely preserved as germinating spores and short-celled protonemata with transverse and oblique cross-walls closely matching those of extant epiphyllous mosses on the surface of the plant-leaf hosts.
  
  
  CONCLUSIONS
  The extension of the epiphyll record back to the middle Cretaceous provides fossil evidence for the appearance of epiphyllous mosses during the diversification of flowering plants, at least 95 million years ago. It also provides substantive evidence for a tropical maritime climate in central North America during the middle Cretaceous.
authors.affiliation: Northwestern University, Department of Earth & Planetary Sciences, Technological Institute, 2145 Sheridan Road, Evanston, Illinois 60208-3130 USA.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Barclay
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: McElwain
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Duckett
authors.forename: Maarten H
authors.initials: MH
authors.lastname: van Es
authors.forename: Anika S
authors.initials: AS
authors.lastname: Mostaert
authors.forename: Silvia
authors.initials: S
authors.lastname: Pressel
authors.forename: Bradley B
authors.initials: BB
authors.lastname: Sageman
mesh_terms: D005075:Biological Evolution; D044002:Bryophyta / Q000254:growth & development; D019068:Bryopsida / Q000254:growth & development; D005580:Fossils; D019770:Lauraceae; D008853:Microscopy / Q000379:methods; D009656:North America; D010802:Phylogeny; D018515:Plant Leaves; D013170:Spores; D014197:Trees; D014329:Tropical Climate
keywords: Bryophyta; Cretaceous; Dakota Formation; Lauraceae; atomic force microscopy; epiphyll; paleobotany; protonema