Fossil bryophytes
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Recent papers in Fossil bryophytes
The pre-Cenozoic bryophyte fossil record is significantly sparser than that of vascular plants or Cenozoic bryophytes. This situation has been traditionally attributed to a hypothesized low preservation potential of the plants. However,... more
The pre-Cenozoic bryophyte fossil record is significantly sparser than that of vascular plants or Cenozoic bryophytes. This situation has been traditionally attributed to a hypothesized low preservation potential of the plants. However, instances of excellent pre-Cenozoic bryophyte preservation and the results of experiments simulating fossilization contradict this traditional interpretation, suggesting that bryophytes have good preservation potential. Studies of an anatomically preserved Early Cretaceous (Valanginian) plant fossil assemblage on Vancouver Island (British Columbia), at Apple Bay, focusing on the cryptogamic flora, have revealed an abundant bryophyte component. The Apple Bay flora hosts one of the most diverse bryophyte assemblages worldwide, with at least nine distinct moss types (polytrichaceous, leucobryaceous, tricostate), one complex thalloid liverwort, and two other thalloid plants (representing bryophyte or pteridophyte gametophytes), which contribute a significant fraction of biodiversity to the pre-Cenozoic fossil record of bryophytes. These results (i) corroborate previous observations and studies, indicating that the preservation potential of bryophytes is much better than traditionally thought; (ii) indicate that the bryophyte fossil record is incompletely explored and many more bryophyte fossils are hidden in the rock record, awaiting discovery; and (iii) suggest that the paucity of the pre-Cenozoic bryophyte fossil record is primarily a reflection of inadequate paleobryological capacity. Résumé : Le registre des bryophytes fossiles du pré-Cénozoïque est significativement plus mince que celui de plantes vasculaires ou de bryophytes du Cénozoïque. Cette situation a été traditionnellement attribuée a ` un hypothétique faible potentiel de préservation de ces plantes. Cependant, des exemples d'une excellente préservation de bryophytes du pré-Cénozoïque et les résultats d'expériences simulant la fossilisation contredisent cette interprétation tradition-nelle, suggérant que les bryophytes ont un bon potentiel de préservation. Des études d'un assemblage de plantes fossiles anatomiquement préservées du Crétacé inférieur sur l'Ile de Vancouver (Colombie Britannique), a ` Apple Bay, se concentrant sur la flore cryptogame, ont révélé une composante importante de bryophytes. La flore d'Apple Bay comporte un des assemblages de bryophytes les plus diversifiés dans le monde, avec au moins neuf types distincts de mousses (Polytrichacées, Leucobryacées, mousses tricostées), une hépatique thalloïde complexe et deux autres plantes thalloïdes (représentant des gamétophytes de bryophyte ou de ptéridophyte), qui contribuent a ` une fraction significa-tive de la biodiversité du registre des bryophytes fossiles du pré-Cénozoïque. Ces résultats (i) corroborent les observations et les études antérieures indiquant que le potentiel de préservation des bryophytes est beaucoup meilleur qu'initialement présumé; (ii) indiquent que le registre de bryophytes fossiles est incomplètement exploré et que beaucoup plus de bryophytes fossiles sont cachés dans les couches de roches, dans l'attente d'être découverts et (iii) suggèrent que la pauvreté du registre des bryophytes fossiles du pré-Cénozoïque est surtout le reflet d'une capacité paléobryologique inadéquate.
PREMISE OF THE STUDY: 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... more
PREMISE OF THE STUDY: 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.
KEY 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).
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.
KEY 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).
- by Mihai Tomescu and +2
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- Paleobotany, Cretaceous life, Bryophytes, Cretaceous
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... more
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. 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. 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...