DOCSLIB.ORG

PLANTS: Implicanons for the EVOLUTION of the LAND PLANTS

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
PLANTS: Implicanons for the EVOLUTION of the LAND PLANTS EVIDENCE FOR A CONDUCTING STRAND IN EARLY SILURIAN (LLANDOVERIAN) PLANTS: IMPLICAnONS FOR THE EVOLUTION OF THE LAND PLANTS KARL J. NIKlAS AND VASSIUKI SMOCOVITIS Made in United States ofAmerica Reprinted from PALEOBIOLOGY Vol. 9, No.2, Spring 1983 Copyright © 1983 The Paleontological Society Paleobiology, 9(2), 1983, pp. 126-137 Evidence for a conducting strand in early Silurian (Llandoverian) plants: implications for the evolution of the land plants Karl J. Niklas and Vassiliki Smocovitis Abstract.-Macerations of fragmented plant compressions of Silurian (Llandoverian) age yield sheets of organic material bearing ridges and depressions (interpreted as corresponding to surficial dimensions of cells), fragments of smooth walled tubular elements, and fragments of tubular elements with differentially thickened walls ("banded tubes"). A fragment of tissue (1.2 mOl long), consisting of smooth walled tubes (17 ± 6.9 ""'01 in diameter), surrounding 2-3 larger (18.8 ± 2.1 ""'01 in diameter) banded tubes, wasisolated from an irregularly shaped, relatively large (1 x 3 mOl) compression. Comparisons between (I) fragments of tubular cell types, not organized into strands, isolated from 122 compressions, and (2) dispersed tubular cell types previously reported from the Massanutten Formation and other Silurian formations (Tuscarora and Clinton), reveal no significant morphologic differences. Comparisons between the organization of smooth-walled and banded tubular cell types found in the tissue strand and the or~anization of cell types in nematophytic plants (Nematothallus, Nematoplexus, Prototaxites) indicate a similarity in construction (tubular) hut a lack of correspondence in organization. The strand of tissue is interpreted as representing part of the internal anatomy of a nonvascular land plant of unknown taxonomic affinity. On the ba-,is of analogy with present-day embryophytes, the strand of tubular cell types is inferred to have functioned as a conductive tissue. The significance of "banded tubes" in Silurian strata is discussed, and it is concluded that, until more is known about the anatomy, morphology, and biochemistry of the parent plant(s), the habitat and systematic affinity of these organisms are conjectural. Karl 1. Niklas and Vassiliki Smocovitis Section of Plant Biology, Cornell University, Ithaca, New York 14853 Accepted: May 3 I, 1983 Introduction analogous in function to supportive or conduct­ Previous studies of Llandoverian and Wen­ ing plant cell types. lockian compression fossils from North America This paper describes additional plant have recognized three categories of microfossils: compressions collected from the localities pre­ (1) tubular elements of variable length having viously reported by Pratt et al. (1978) in the smooth and banded (=differentially thickened) lower Massanutten Sandstone, Virginia. Among walls, (2) membranous sheets of organic mate­ the various cell and tissue fragments recovered rial bearing irregularly shaped depressions, and from 122 plant fragments, a single strand of tis­ (3) alete and trilete spores, and tetrads (Gray sue was isolated consisting of smooth-walled tu­ and Boucot 1977; Pratt et aI. 1978; Strother and bular elements surrounding a small number of Traverse 1979). Llandoverian microfossils from banded tubular cell types. This fragment of tis­ the Massanutten Formation of Virginia are sue, interpreted to be part of the internal anat­ thought to be the fragmented remains of a non­ omy of an as yet unspecified macrophyte, is the vascular macrophyte of unknown taxonomic af­ largest fragment thus far reported for the Mas­ finity based on an inferred fluvial depositional sanutten localities, and provides evidence for a environment, the presence of spores, and chem­ discrete organization of smooth and banded ical composition (Pratt et aI. 1978; Niklas and tubes. In addition to the new morphologic in­ I3 Pratt 1980). Owing to poor preservation, the formation, stable isotope (6C ) analyses of du­ general morphology and internal organization plicate fossils are presented. In conjunction with of these plants were previously unknown. How­ previously reported organic chemical profiles, er I Pratt et aI. (1978) have speculated that the these data provide some insight into the bio­ th and banded tubes represent fragments chemical composition of the Massanutten plant bular-filamentous tissue (nematophytic), remains. The additional morphologic and bio­ , e Paleontological Society. All rights reserved. 0094.8373/8310902--o00S/$I.00 EVOLUTION OF LAND PLANTS 127 30 chemical data presented here and elsewhere (d. SKEWNESS" fbt = 0 614* KURTOSIS'" bz = 254 t Niklas 1982) are relevant to the biologic inter­ 25 KURTOSIS = 0 =0.19* 25 24 n = 122 pretation of the Massanutten fossils and provide "z w i = 1.32 a context for evaluating current concepts on the ! 20 19 v =.!051 u w first occurrence of the land plants and the sub­ "­ 16 ""­ 15 sequent appearance of tracheophytes (Banks o 13 a: 10 1975; Gray and Boucot 1977, 1979). w 10 <D =>" Materials and Methods z Samples of fossiliferous siltstone were collect­ o 0.26- 0.51- 0.76- 1.01 1.26- U51- 1.76- 2.01- 2.26- 251­ ed from horizons designated by Pratt et al. (1978) 0.50 075 1.00 I 25 1.50 1.75 2.00 2.25 2.50 2.75 DIAMETER (MM) SIZE CLASSES as 8-9 in the lower Massanutten Sandstone along route 678 at the gap of Passage Creek, 6 km FIGURE 1. Frequency vs. size class distribution histogram of 122 plant compressions measured on bedding surfaccs of southeast of Strasburg, Virginia. The age of the siltstone from the lower Massanutten Sandstone, Virginia. Massanutten compression fossils is reported as Based on N = 122, the mean diameter (i) c.9uals 1.32 ± most probably Llandoverian A or B (Pratt et al. 0.51. * = Analyses for skewness, based on Vb" were com­ puted and compared to one-tail 5% and 1% significance 1978). levels, since N = 150. Two methods to compute Kurtosis Two shale partings, each consisting of part (t, :j:) were used: = value for a normal distribution is b. = and counterpart, measuring 16 x 8 em and 17 x 9 3.0, Q = value for a normal distribution, a = 0.80 (cf. Snedecor and Cochran 1980). em were examined, and revealed 122 compres­ sion fossils on their bedding surface (roughly 281 2 cm ). The maximum lateral dimension of each Collection numbers designating slides, SEM compression was measured with a Helios mi­ stubs, and duplicate material in the Paleobotan­ crocaliper (Modern Tools Corp., Woodside, ical Collections (Plant Science Building) at Cor­ N. Y.) and a histogram of size classes construct­ nell are: compression fossils No. 1203-1204; ed. Additional shale partings with compressions Slide No. 23-210; SEM stub No. 1-16. were reserved for stable isotope analyses. Spec­ imens were photographed with reflected light, Results and representative specimens were removed The compressions are circular, elliptical-bi­ from the larger partings for SEM by means of furcate, to irregular in shape (Figs. 2-7). The a dental drill cutting rotor. Macerations of histogram of compression size classes, based on compressions, grouped according to size class the maximum dimension of 122 specimens, is (0.26-0.50,0.51-0.75, ...,2.51-2.75 mm, cE. skewed (vb; = 0.614), leptokurtic (a = 0.19), Fig. 1), were obtained by constructing paraffin and has a mean of 1.32 ± 0.51 mm (Fig. 1). wells around specimens and treating them with Scanning electron microscopy (SEM) of HF acid for 30 min to 48 h. Macerations were compressions, mechanically removed from silt­ neutralized with washings of distilled water, and stone parting, shows surficial depressions and organic debris removed by pipette for light and ridges continuous over the surface of the fossils scanning microscopy. examined (5 in number) (Figs. 8-10). Dimen­ I3 Stable isotope (OC ) analyses of compression sions of randomly sampled depressions are 6.7 fossils were performed by Krueger Enterprises, ± 1.6 /-tm by 8.2 ± 2.1 /-tm (N = 100) and are Inc., Geochron Laboratories Division (24 irregular to elliptical in shape. Surfaces of in Blackstone Street, Cambridge, Mass.), and are situ compressions are sometimes perforated, with based on samples designated CR-16669 and CR­ holes corresponding in dimensions to surficial 16670 by that facility. depressions (6.8 ± 1.8 /-tm by 7.9 ± 20 /-tm, Statistical comparisons among the morpho­ N = 28) (Fig. 10). Cellulose acetate peels of 5 logic features of tubular cell types are based on fragments haviI).g an elliptical to bifurcate out­ standard 2-sample t-test, corrected by a Bon­ line resulted in the removal of organic material ferroni inequality to df 0.05/N (where N = the having no demonstrable organization (Figs. 11­ number of comparisons and df = degrees of 12). freedom) (cf. Snedecor and Cochran 1980). Maceration of 117 compressions produced 50 128 KARL J. NIKLAS & VASSILIKI SMOCOVITIS sheets of irregL bearing an Ope rounding transIt /-tm by 7.9 ::t l These dimensiOi for surficial dep under SEM (Fig: of tubular cells ations: (1) smoot 3 1 /-tm in diam (Figs. 15-19); (;; 11-35 /-tm in di with pronounce 20); and (3) tubt thickened walls 3.6 /-tm, N = 2. "tubes" ranged 6.6),26-110 J.l-rr 7.9), respective) tubular elemen~ ken ends. Stati tubes indicate longer fragment­ walled tubes. 5. tubular element longitudinally a fragments of tu wall constructic alignment to or were found onL greater in diamE sion). Maceration oj (1 mm wide, 3 r: of tissue (1.2 mr (Fig. 22). Both· transversely, anc length was ocelt monstrable cell FIGURES 2-12. Re Compressions on su surface, normal to t (Figs. 22-25) was is from which strand v ularities (No. 1204). of matrix (No. 1204 lOA). 280x. Fig. 9, lOA). 280x. Fig. l( ~etate peels of com ,0. 129-130). 22x. EVOLUTION OF LAND PLANTS 129 sheets of irregularly shaped organic material strand was composed of an indeterminate num­ bearing an opaque reticulum of ridges sur­ ber of longitudinally aligned, externally smooth­ rounding translucent areas measuring 6.5 ± 1.3 walled tubes (17 ± 6.9 /Lm in diameter, N = /Lm by 7.9 ± 2.1 /Lm (N = 50) (Figs.
Load more

Recommended publications
  • The Origin and Early Evolution of Plants on Land
    review article The origin and early evolution of plants on land Paul Kenrick & Peter R. Crane . The origin and early evolution of land plants in the mid-Palaeozoic era, between about 480 and 360 million years ago, was an important event in the history of life, with far-reaching consequences for the evolution of terrestrial organisms and global environments. A recent surge of interest, catalysed by palaeobotanical discoveries and advances in the systematics of living plants, provides a revised perspective on the evolution of early land plants and suggests new directions for future research. The origin and early diversification of land plants marks an interval Eoembryophytic (mid-Ordovician [early Llanvirn: ϳ476 Myr] to of unparalleled innovation in the history of plant life. From a simple Early Silurian [late Llandovery: ϳ432 Myr])3. Spore tetrads (com- plant body consisting of only a few cells, land plants (liverworts, prising four membrane-bound spores; Fig. 2d) appear over a broad hornworts, mosses and vascular plants) evolved an elaborate two- geographic area in the mid-Ordovician and provide the first good phase life cycle and an extraordinary array of complex organs and evidence of land plants3,26,29. The combination of a decay-resistant tissue systems. Specialized sexual organs (gametangia), stems with wall (implying the presence of sporopollenin) and tetrahedral an intricate fluid transport mechanism (vascular tissue), structural configuration (implying haploid meiotic products) is diagnostic tissues (such as wood), epidermal structures for respiratory gas of land plants. The precise relationships of the spore producers exchange (stomates), leaves and roots of various kinds, diverse within land plants are controversial, but evidence of tetrads and spore-bearing organs (sporangia), seeds and the tree habit had all other spore types (such as dyads) in Late Silurian and Devonian evolved by the end of the Devonian period.
    [Show full text]
  • The Questionable Origin of Early Land Plants from Algae
    The Palaeobotanist, 28-29: 423-426, 1981. THE QUESTIONABLE ORIGIN OF EARLY LAND PLANTS FROM ALGAE F. P. JONKER Laboratory of Palaeobotany and Palynology, The State University of Utrecht Heidelberglaan 2, The Netherlands ABSTRACT The paper deals with the rise of terrestrial plant life in the Early Devonian. The view is developed that apart from Psilophytes some algal groups may have given rise to (semi-) land plants. (Semi-) land algae, however, have not been successful in competition with land invading Tracheophytes and became extinct after a relatively short existence. Key-words - Algae, Early land plants, Terrestrial vegetation, Psilophytes, Early Devonian. 5lTU'll'li ~ tftlif 'fiT JiTcm;iT ~ ~ ~W.f - 1'%0 tfto ~ ~ mlt-qz;f 5lTU'll'li ~ iT ~ 'TT~-;;r')q.; ifi ~ ~ w<rf.mr ~ I ~ ~ Olf'ffi f'f;m 'flIT ~ fif; l;li'.5'tl!flI<;<i)li'iifi ~rncr ~ ~ <!~ ~ '+IT (ri) "!-~ 'fiT ~ gm ~ I cr~, ~r ~!flT~ ifi ~ iT (>;f~) ~lf!lT9m~!fl<'f;r@ ~ crqf >;fq-~ >;J~q'lllf"l'll ~ ifi w:rrq: ~ \[1 'Tit I The two above mentioned papers prove J.whatM. SchopfI presume(1978)wasshowedhis finalthatpaper,the again that some knowledge of modern larger INtill then enigmatic, North-American, algae, their life form, and their reproduc• Devonian genus Foerstia White belonged tion and life cycle is needed in studying to the Phaeophyta and should be regarded and interpreting Silurian and Devonian as a marine "fucoid". The presumed plant megafossils which are too often attri• spore, or megaspore, tetrads represented buted to Psilophytes or other Pteridophytes. egg cells of which the coats were resistant.
    [Show full text]
  • The Foerstia Zone of the Ohio and Chattanooga Shales
    The Foerstia Zone of the Ohio and Chattanooga Shales GEOLOGICAL SURVEY BULLETIN 1294 H The Foerstia Zone of the Ohio and Chattanooga Shales By J. M. SCHOPF and J. F. SCHWIETERING CONTRIBUTIONS TO STRATIGRAPHY GEOLOGICAL SURVEY BULLETIN 1294-H An explanation for the strati graphic zonation of the fossils and a report on a newly discovered occurrence of the Foerstia zone in western Ohio UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1970 UNITED STATES DEPARTMENT OF THE INTERIOR WALTER J. HICKEL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director Library of Congress catalog-card No. 73-607393 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 30 cents (paper cover) CONTENTS Page Abstract ..... ....................... ...................... ............................................... HI Introduction ..................... ............ .................. ................................................. 1 Earlier reports .... ..................... ... ..... ... ......................................... 2 The "spores" of Foerstia ................. ... ............. _........... .. 4 Littoral control ............................. ... ............ ........................................ 6 Stratigraphic occurrence of Foerstia ............. ....... ..................................... 8 A new Foerstia locality ........ ... ............................. ................................... ..... 12 Summary ......................................................................................._..._..............-....
    [Show full text]
  • Organically-Preserved Multicellular Eukaryote from the Early Ediacaran Nyborg Formation, Arctic Norway Received: 30 November 2018 Heda Agić 1,2, Anette E
    www.nature.com/scientificreports OPEN Organically-preserved multicellular eukaryote from the early Ediacaran Nyborg Formation, Arctic Norway Received: 30 November 2018 Heda Agić 1,2, Anette E. S. Högström3, Małgorzata Moczydłowska2, Sören Jensen4, Accepted: 12 September 2019 Teodoro Palacios4, Guido Meinhold5,6, Jan Ove R. Ebbestad7, Wendy L. Taylor8 & Published online: 10 October 2019 Magne Høyberget9 Eukaryotic multicellularity originated in the Mesoproterozoic Era and evolved multiple times since, yet early multicellular fossils are scarce until the terminal Neoproterozoic and often restricted to cases of exceptional preservation. Here we describe unusual organically-preserved fossils from mudrocks, that provide support for the presence of organisms with diferentiated cells (potentially an epithelial layer) in the late Neoproterozoic. Cyathinema digermulense gen. et sp. nov. from the Nyborg Formation, Vestertana Group, Digermulen Peninsula in Arctic Norway, is a new carbonaceous organ-taxon which consists of stacked tubes with cup-shaped ends. It represents parts of a larger organism (multicellular eukaryote or a colony), likely with greater preservation potential than its other elements. Arrangement of open-ended tubes invites comparison with cells of an epithelial layer present in a variety of eukaryotic clades. This tissue may have beneftted the organism in: avoiding overgrowth, limiting fouling, reproduction, or water fltration. C. digermulense shares characteristics with extant and fossil groups including red algae and their fossils, demosponge larvae and putative sponge fossils, colonial protists, and nematophytes. Regardless of its precise afnity, C. digermulense was a complex and likely benthic marine eukaryote exhibiting cellular diferentiation, and a rare occurrence of early multicellularity outside of Konservat-Lagerstätten. Te late Neoproterozoic interval was a critical time of turbulent environmental changes and key evolutionary innovations.
    [Show full text]
  • Retallack 2015 Palmerton Silurian
    XXX10.1144/jgs2015-022G. J. RetallackSilurian vegetation 2015 2015-022research-articleResearchDownloaded article10.1144/jgs2015-022Silurian vegetation stature and density inferred from fossil soils and plantsfrom in Pennsylvania, USAGregory J. Retallack http://jgs.lyellcollection.org/ at University of Oregon on August 5, 2015 Research article Journal of the Geological Society Published Online First doi:10.1144/jgs2015-022 Silurian vegetation stature and density inferred from fossil soils and plants in Pennsylvania, USA Gregory J. Retallack Department of Geological Sciences, University of Oregon, Eugene, OR 97403-1272, USA * Correspondence: [email protected] Abstract: Silurian fossil plants range from small vascular plants (rhyniophytes) to moderately large fungi (nematophytes), but give little idea of the stature, rooting depth and plant density of vegetation on land. Silurian to earliest Devonian palaeo- sols from the Bloomsburg Formation show unusually deep bioturbation of several distinct kinds. Surface ground-parallel rhizomes of vascular land plants (to 20 cm deep) are penetrated by burrows like those of millipedes (to 80 cm), but the deep- est stratum (down to 2 m below the surface) has features interpreted as bioturbation by fungal hyphae and rhizines. Plant-like axes associated with palaeosols are evidence of vegetation with three distinct tiers above ground as inferred from diameters using allometric scaling equations. Nematophytes (Germanophyton psygmophylloides), up to 1.3 m tall, formed a tier above herbaceous vascular land plants (30 cm) and ground cover (<2 cm tall) of thallose organisms and litter. Drab haloed plant bases in the surface of palaeosols demonstrate that nematophytes grew densely (up to 51 m−2) with spacing (20 cm) that closed canopy in seasonally dry wetland palaeosols, comparable with modern marsh vegetation.
    [Show full text]
  • Paul Klee Strother Education Academic
    PAUL KLEE STROTHER Fellow, American Association for the Advancement of Science b. September 16, 1953 Department of Earth & Environmental Sciences Alexandria, Virginia Weston Observatory of Boston College Married, two children 381 Concord Rd., Weston MA 02493 tel. (617) 552-8395 email: [email protected] EDUCATION Ph.D. Biology, Harvard University, 1980 Thesis: Microbial Communities from Precambrian Strata B.S. Biology, Pennsylvania State University, 1975 ACADEMIC EMPLOYMENT 1997—present, Research Professor, Boston College 2012 Visiting Research Scientist, Institut für Geowissenschaften, Goethe Universität Frankfurt Am Main, Germany 2008-9, 2011 Professeur Invité and visiting research scientist, Géosystèmes USTL 1, Villeneuve D'Ascq, France 1992—1996 Associate Research Professor, Boston College 1992—1993 Visiting Lecturer, U Mass Lowell 1984—1991 Assistant Professor of Geology, Boston University 1985—1991 Associated Faculty, Department of Biology, Boston University 1983—1984 Visiting Assistant Professor of Geology, Boston University 1982—1983 Assistant Professor of Geology, Dickinson College 1980—1982 Postdoctoral Fellow in Biology, Harvard University 1975—1980 Research Fellow, Paleobotanical Laboratory, Harvard University TEACHING EXPERIENCE Boston College 1996-current: GE146 Origin and Evolution of Life on Earth, GE246 Sedimentology & Stratigraphy, GE330 Paleontology (now, Paleobiology), GE335 Geobiology, GE799 Readings and Research, GE801 Thesis Seminar Pollen & Spores Master Class (Instructor) University of Utrecht, TNO, July 8-12,
    [Show full text]
  • Resistant Tissues of Modern Marchantioid Liverworts Resemble Enigmatic Early Paleozoic Microfossils
    Resistant tissues of modern marchantioid liverworts resemble enigmatic Early Paleozoic microfossils Linda E. Graham*†, Lee W. Wilcox*, Martha E. Cook‡, and Patricia G. Gensel§ *Department of Botany, University of Wisconsin, Madison, WI 53706-1381; ‡Department of Biological Sciences, Illinois State University, Normal, IL 61790-4120; and §Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280 Edited by Lynn Margulis, University of Massachusetts, Amherst, MA, and approved June 7, 2004 (received for review January 22, 2004) Absence of a substantial pretracheophyte fossil record for bryo- any lineage of vascular plants that has extended to the present phytes (otherwise predicted by molecular systematics) poses a time (8, 9) and the megafossil record. Late Ordovician (Caradoc, major problem in our understanding of earliest land-plant struc- Ϸ450 million years old) spores having distinctive layered walls ture. In contrast, there exist enigmatic Cambrian–Devonian micro- that among modern plants are found only among liverworts fossils (aggregations of tubes or sheets of cells or possibly a (occurring within fragments of enclosing material interpreted as combination of both) controversially interpreted as an extinct sporangial epidermis) are interpreted as liverwort microfossils group of early land plants known as nematophytes. We used an (10). However, the earliest megafossils (of Late Silurian age, innovative approach to explore these issues: comparison of tube Ϸ425 million years ago) that are accepted as remains of bryo- and cell-sheet microfossils with experimentally degraded modern phytes, with many cellular features matching those of liverworts liverworts as analogues of ancient early land plants. Lower epi- (11), considerably postdate the earliest fossils attributed to dermal surface tissues, including rhizoids, of Marchantia polymor- vascular plants or pretracheophyte polysporangiophytes (12, 13).
    [Show full text]
  • Early Silurian Terrestrial Biotas of Virginia, Ohio, and Pennsylvania: an Investigation Into the Early Colonization of Land (284 Pp.)
    LATE ORDOVICIAN – EARLY SILURIAN TERRESTRIAL BIOTAS OF VIRGINIA, OHIO, AND PENNSYLVANIA: AN INVESTIGATION INTO THE EARLY COLONIZATION OF LAND A dissertation presented to the faculty of the College of Arts and Sciences of Ohio University In partial fulfillment of the requirements for the degree Doctor of Philosophy Alexandru Mihail Florian Tomescu November 2004 © 2004 Alexandru Mihail Florian Tomescu All Rights Reserved This dissertation entitled LATE ORDOVICIAN – EARLY SILURIAN TERRESTRIAL BIOTAS OF VIRGINIA, OHIO, AND PENNSYLVANIA: AN INVESTIGATION INTO THE EARLY COLONIZATION OF LAND BY ALEXANDRU MIHAIL FLORIAN TOMESCU has been approved for the Department of Biological Sciences and the College of Arts and Sciences by Gar W. Rothwell Distinguished Professor of Environmental and Plant Biology Leslie A. Flemming Dean, College of Arts and Sciences TOMESCU, ALEXANDRU MIHAIL FLORIAN. Ph.D. November 2004. Biological Sciences Late Ordovician – Early Silurian terrestrial biotas of Virginia, Ohio, and Pennsylvania: an investigation into the early colonization of land (284 pp.) Director of Dissertation: Gar W. Rothwell An early phase in the colonization of land is documented by investigation of three fossil compression biotas from Passage Creek (Silurian, Llandoverian, Virginia), Kiser Lake (Silurian, Llandoverian, Ohio), and Conococheague Mountain (Ordovician, Ashgillian, Pennsylvania). A framework for investigation of the colonization of land is constructed by (1) a review of hypotheses on the origin of land plants; (2) a summary of the fossil record of terrestrial biotas; (3) an assessment of the potential of different continental depositional environments to preserve plant remains; (4) a reevaluation of Ordovician-Silurian fluvial styles based on published data; and (5) a review of pertinent data on biological soil crusts, which are considered the closest modern analogues of early terrestrial communities.
    [Show full text]
  • Further Evidence for Fungivory in the Lower Devonian (Lochkovian) of the Welsh Borderland, UK
    PalZ https://doi.org/10.1007/s12542-019-00503-9 RESEARCH PAPER Further evidence for fungivory in the Lower Devonian (Lochkovian) of the Welsh Borderland, UK Dianne Edwards1 · Lindsey Axe1 · Jennifer L. Morris1 · Lynne Boddy2 · Paul Selden3,4 Received: 20 March 2019 / Accepted: 4 November 2019 © The Author(s) 2020 Abstract The recent demonstrations that widespread mid-Palaeozoic Prototaxites and other nematophytes had fungal afnities indicate that terrestrial fungi were important elements in carbon cycling in the Early Devonian. Here, we provide evidence for their participation in the recycling of nutrients by early terrestrial invertebrates. Evidence is in the form of coprolites, both those associated with nematophytes or containing their fragmentary remains. Cylindrical coprolites consistently associated with fungal mats are placed in a new ichnospecies, Bacillafaex myceliorum. Their contents are granular to amorphous, sugges- tive of complete digestion of the ingested hyphae, with the inference of possession of chitinases in the digestive tracts of the consumers. A further single example comprises a cluster of cylindrical bodies attached to the lower surface of a Nemato- thallus fragment. Here, homogenisation was less complete, with traces of hyphae remaining. Terrestrial animal fossils have not been found at the locality, but scorpions, pseudoscorpions, Opiliones, mites, centipedes (carnivores) and millipedes, and Collembola (detritivores) have been recorded from the slightly younger Rhynie cherts. Studies of fungivory in extant arthropods have concentrated on Collembola and, to a lesser extent, mites, but their faecal pellets are much smaller than the fossil examples. Millipedes, based on body size and faeces of extant forms, are considered more realistic producers, but little is known about fungal feeding in these animals.
    [Show full text]
  • Palynology and Microfacies of Lower Devonian Mixed Carbonate−Siliciclastic Deposits in Podolia, Ukraine
    Palynology and microfacies of Lower Devonian mixed carbonate−siliciclastic deposits in Podolia, Ukraine PAWEŁ FILIPIAK, MICHAŁ ZATOŃ, HUBERT SZANIAWSKI, RYSZARD WRONA, and GRZEGORZ RACKI Filipiak, P., Zatoń, M., Szaniawski, H., Wrona, R., and Racki, G. 2012. Palynology and microfacies of Lower Devonian mixed carbonate−siliciclastic deposits in Podolia, Ukraine. Acta Palaeontologica Polonica 57 (4): 863–877. Investigation of mixed carbonate−siliciclastic Lower Devonian deposits have been carried out in the Ivanye Zolote and Ustechko sections in Podolia, Ukraine. Based on palynomorph evidence, the age of the samples studied is late Lochkovian, not older than the NM Oppel Miospore Zone, specifically the Si Lineage Zone. The presence of acritarchs and chitinozoans points to dominantly marine depositional conditions. However, a regressive environmental change to− ward more brackish conditions is indicated by a decrease in the taxonomic diversity of acritarchs in the topmost samples, the simultaneous disappearance of chitinozoans, and an increase in leiosphaerid frequency. Furthermore, evolution of limestone microfacies demonstrates a progressive transition from a shrinking marine basin toward a brackish, storm−af− fected muddy lagoon, manifested by recurrent profusion of impoverished, mostly opportunistic and euryhaline shelly benthos (nuculanid bivalves, leperditicopids and other ostracods, terebratulid brachiopods), chaetetid demosponges and diverse ichthyofauna. The association of plant (mainly nematophytes and some tracheids) and animal (eurypterid, ?scor− pion, and possibly other arthropod) remains points to the presence of nearby Early Devonian wetland vegetation, provid− ing food and shelter for various semi−aquatic and other terrestrial arthropods. Key words: Eurypterids, palynostratigraphy, palynofacies, carbonate microfacies, cuticles, Lower Devonian, Podolia. Paweł Filipiak [[email protected]], Michał Zatoń [[email protected]], and Grzegorz Racki [grzegorz.racki@us.
    [Show full text]
  • Early Land Plant Phytodebris
    Downloaded from http://sp.lyellcollection.org/ by guest on September 27, 2021 Early land plant phytodebris Charles H. Wellman1* and Alexander C. Ball1,2 1Department of Animal & Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield S10 2TN, UK 2Department of Earth Sciences, Natural History Museum (London), South Kensington, London SW7 5BD, UK CHW, 0000-0001-7511-0464; ACB, 0000-0002-2687-553X *Correspondence: c.wellman@sheffield.ac.uk Abstract: Historically, phytodebris (often considered a type of non-pollen palynomorph – NPP) has played a prominent role in research into the fossil record of early land plants. This phytodebris consists of cuticles and cuticle-like sheets, various tubular structures (including tracheids and tracheid-like tubes) and sundry other enigmatic fragments. Initial research focused on elucidating their morphology, attempts to identify them in situ in plant megafossils and comparisons with potentially homologous structures in extant plants. The fragmen- tary nature of these remains, and associated difficulties in positively identifying their presence in fossil/extant plants, resulted in vigorous debate regarding what many of these microfossils actually represented and their rel- evance to early land plant studies. More recently a wider array of analytical techniques has been applied (e.g. ultrastructural analysis, geochemistry and taphonomic experiments). However, positive identification of the affinities of at least some of these enigmatic fossils remained elusive. Ongoing investigations based on excep- tionally preserved material from Lagerstätten (charcoalified and silicified) seem to have finally demonstrated that the more enigmatic of these remains derive from nematophytes that probably represent fungi and possibly also lichenized fungi. Land plants (embryophytes) produce potentially fos- host sediment by palynological acid-maceration tech- silizable parts both throughout their lives and upon niques.
    [Show full text]
  • Resistant Tissues of Modern Marchantioid Liverworts Resemble Enigmatic Early Paleozoic Microfossils
    Resistant tissues of modern marchantioid liverworts resemble enigmatic Early Paleozoic microfossils Linda E. Graham*†, Lee W. Wilcox*, Martha E. Cook‡, and Patricia G. Gensel§ *Department of Botany, University of Wisconsin, Madison, WI 53706-1381; ‡Department of Biological Sciences, Illinois State University, Normal, IL 61790-4120; and §Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280 Edited by Lynn Margulis, University of Massachusetts, Amherst, MA, and approved June 7, 2004 (received for review January 22, 2004) Absence of a substantial pretracheophyte fossil record for bryo- any lineage of vascular plants that has extended to the present phytes (otherwise predicted by molecular systematics) poses a time (8, 9) and the megafossil record. Late Ordovician (Caradoc, major problem in our understanding of earliest land-plant struc- Ϸ450 million years old) spores having distinctive layered walls ture. In contrast, there exist enigmatic Cambrian–Devonian micro- that among modern plants are found only among liverworts fossils (aggregations of tubes or sheets of cells or possibly a (occurring within fragments of enclosing material interpreted as combination of both) controversially interpreted as an extinct sporangial epidermis) are interpreted as liverwort microfossils group of early land plants known as nematophytes. We used an (10). However, the earliest megafossils (of Late Silurian age, innovative approach to explore these issues: comparison of tube Ϸ425 million years ago) that are accepted as remains of bryo- and cell-sheet microfossils with experimentally degraded modern phytes, with many cellular features matching those of liverworts liverworts as analogues of ancient early land plants. Lower epi- (11), considerably postdate the earliest fossils attributed to dermal surface tissues, including rhizoids, of Marchantia polymor- vascular plants or pretracheophyte polysporangiophytes (12, 13).
    [Show full text]