Moss fossils

The earliest known moss fossil is from the early Carboniferous period, about 320 million years ago. Mosses are not well-represented in the fossil record because their soft tissue is not well preserved. An examination of extant species indicates that bryophytes are a polyphyletic group. They appear to have evolved from more than one ancestral line. 

The majority of the moss fossil record cannot provide us with useful information about the possible ages of nodes, for the most part being too recent or too poorly characterized to be used as constraints or to contribute much to our understanding of the timing and sequence of evolutionary events (Krassilov and Schuster, 1984 Miller, 1984). However, our age estimates can possibly suggest something about our interpretation of the fossils. Only fossils credibly considered to be pleurocarpous are discussed here (see also Ignatov and Shcherbakov, Chapter 16). 

J. T. Moss, Jr. and J. T. Moss. Enhanced oil recovery using hydrogen peroxide injection. US DOE Fossil Energy Rep NIPER/BDM-0086, Tejas Petrol Engineers Inc, 1994. 

Also needed is an examination of paleosols within this interval for evidence of fossil mosses, which would have been more deeply rooted than liverworts and so have accelerated weathering and carbon sequestration. Rare Late Ordovician mosslike megafossils (Snigirevskaya et ah, 1992) and spores (N0hr-Hansen and Koppelhus, 1988) support indications from cladistic analysis (Kenrick and Crane, 1997) for a latest Ordovician origin of mosses. 

There are only a few fossils of liverworts and mosses and there are no fossils of hornworts. This is because the soft tissue of these bryophytes does not fossilize well. The oldest known liverwort fossil is from the late Devonian period, about 350 million years ago. Most botanists believe that they originated long before this. 

Ochyra, R. (1986) Sciaromiadelphus A. Abr. I. Abr. The relationship between extant and fossil moss specimens. Journal of the Hattori Botanical Laboratory, 61 309-332. 

Selected Palaeozoic and Mesozoic mosses are discussed, focusing on their possible relationships to pleurocarpous groups. Among thm. Palaeozoic, Triassic and some Jurassic fossils are similar to pleurocarps in some respects, but some other peculiarities of these mosses make their immediate placement into extant groups difiScult. One new genus and species, Palaeodichelyma sinitzae, is described from the Upper Jurassic of Transbaikalia. This fossil moss is probably the most similar to pleurocarps among the pre-Cenozoic fossils. 

The undoubted pleurocarps, however, are almost absent or at least extremely rare in earlier deposits. This fact, along with the other evidence, leads to the tentative conclusion (e.g.. Buck, 1991), that the evolution of pleurocarps followed the habitat diversification of the angiosperms, i.e., occurred in the Cretaceous. At the same time, an analysis of fossil data lead Krassilov and Schuster (1984) to the conclusion that the pleurocarpous mosses appeared no earlier than the Jurassic. 

Ignatov, M. S. (1992) Bryokhutuliinia jurassica, gen. et spec, nova, a remarkable fossil moss from Mongolia. Journal of the Hattori Botanical Laboratory, 71 377-388. 

Smoot, E. L. and Taylor, T. N. (1986) Structurally preserved fossil plants from Antarctica. II. A Permian moss from the Transantarctic Mountains. American Journal of Botany 73 1683-1691. 

Fossils of organisms that are clearly mosses exist from the Palaeozoic, from the Carboniferous and Permian periods onwards (see Krassilov and Schuster, 1984 and Ooslendorp, 1987 for comprehensive discussion of these), but it is evident from our results that the majority of lineages of extant mosses originated in the Mesozoic, with considerable diversification occurring in the Cretaceous and in the Cenozoic (Figure 17.1). 

It must also be noted that, if the fossil record accurately reflects the diversity of terrestrial ecosystems, the dense, complex angiosperm forests that we currently know, with their rich diversity of habitats, would have appeared relatively late in the process of diversification of angiosperm lineages (Behrensmeyer, 1992) further emphasizing the uncoupling of pleurocarpous moss diversification from... 

Miles, R.S. (1973) Relationships of acanthodians , in Greenwood, P.H., Miles, R.S. and Patterson, C. (eds) Interrelationships of fishes, London Academic Press, pp. 63—103. Moss, M.J. (1977) Skeletal tissues in sharks , American Zoologist, 17, 335—42. Moy-Thomas, J.A. (1936) The structure and affinities of the fossil elasmobranch fishes from the Lower Carboniferous of Glencartholm, Eskdale , Proceedings of the Zoological Society of London B, 1936, 762—88. 

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