The 18th Plant Taphonomy Meeting

The 18th Plant Taphonomy Meeting was held in Vienna (David K. Ferguson, Christa Hofmann), Department of Palaeontology, Geocentre, Austria, 26th of January 2008.


[*] 9.45-10.00: Welcome address, announcements

Mesozoic themes

[*] 10.00-10.20: Carole T. Gee. Sauropod food plants from physiological and paleobotanical perspectives.

[*] 10.20-10.30: Barbara Meller. Taphonomic considerations on a new plant-bearing locality from Lunz (Austria, Late Triassic, Carnian) or How to interpret plant fossils from mining waste heaps? (Poster)

[*] 10.30-10.50: Break

[*] 10.50-11.10: Evelyn Kustatscher & Johanna H. A. van Konijnenburg-van Cittert. Neocalamites asperrimus (Franke) Shen 1990, a morphospecies for Triassic sphenophyte "cortical structures".

[*] 11.10-11.30: Lutz Kunzmann, Barbara A. R. Mohr & Mary E. C. Bernardes-de-Oliviera. Taphonomic aspects of the late Early Cretaceous Crato flora (Brazil).

[*] 11.30-11.50: Break

Actuopalaeobotanical themes

[*] 11.50-12.10: Christa-Ch. Hofmann & A. Hugh N. Rice. Monospecific "leaf-jams" in the seasonal/ephemeral Hoanib River in the northern Namib (NW Namibia).

[*] 12.10-12.30: Margaret E. Collinson, Andrew C. Scott, Vicky Hudspith, Rachel Brain, David Steart, Laura McParland & Sharon Gibbons. Discussion on the production and fate of charcoals following a heathland and peatland fire in Surrey, UK.

[*] 12.30-14.00: Lunch

[*] 14.00-15.30: Round-table discussion about the influence of facies on the composition of plant assemblages led by Prof. Robert A. Spicer (Open University) and Prof. Christa-Charlotte Hofmann (Vienna University).

[*] 15.30-15.50: Break

[*] 15.50-16.30: General discussion, plans for future meetings, information about the joint International Palynological Congress-International Organisation of Palaeobotany Conference in Bonn, 30 August-5 September 2008.


Sauropod Food Plants from Physiological and Paleobotanical Perspectives

Carole T. Gee
University of Bonn

The issue of sauropod food plant preferences remains a puzzling and unresolved one. Dinosaur paleontologists have approached this problem variously by using skull, jaw, and dental morphology, and even neck posture and browsing height. Paleobotanists, on the other hand, have been limited to spectulation, basing their arguments either on the theoretical availability of certain plant groups (the "fern prairies" of the Morrison Formation of Taggert and Cross) or the hypothetical palatability of certain taxa (i.e., cycads, bennettites, cheirolepids, and ginkgophytes) on account of the softness of their plant tissue or lack of phytochemicals (as posited by Bruce Tiffney). The few instances of fossilized "stomach" contents and coprolites assuming to have originated from herbivorous dinosaurs are of little help owing to their scarcity, questionable authenticity, and the difficulty of pinpointing the exact producer of the remains. Our DFG-funded Research Unit on Sauropod Biology and the Evolution of Gigantism has approached this issue in a fundamentally different way by investigating the comparative nutritional quality of the nearest living relatives of the Mesozoic flora. Contrary to common paleobotanical wisdom, in vitro fermentation experiments have shown that Equisetum, Araucaria, Ginkgo, and some ferns such as Angiopteris are very good to excellent sources of energy for herbivores, while podocarps, cycads, and tree ferns make for very poor herbivore fodder. Testing these results with the fossil record is the next step. Under current investigation are: 1) the co-occurrence of sauropod and plant taxa in major Jurassic faunas, 2) the paleobotany of a large megafossil flora and diverse palynoflora occurring in a dinosaur bonebed in the Late Jurassic Morrison Formation of Wyoming, and 3) the phylogenetic analysis of Araucaria as insight into the evolution of morphologies in the genus that may have developed in response to dinosaur herbivory. With respect to plant taphonomy, preservational biases most likely have led to the huge gaps in the paleobotanical record of the famous, dinosaur-bearing sediments of the Morrison Formation and hence the raging controversy over the Morrison flora and climate regime.

Taphonomic considerations on a new plant-bearing locality from Lunz (Austria, Late Triassic, Carnian) or How to interpret plant fossils from mining waste heaps?

Barbara Meller
Institute of Palaeontology, University of Vienna & Naturkundliche Station Lunz am See, Austrian Academy of Sciences

The late Triassic flora from Lunz am See (Lower Austria) is famous, with numerous documented specimens in collections within Europe. Despite this, their taphonomy has not yet been properly accounted for. Plant fossils from the Lunz Formation were mainly collected in the 19th century and to a lesser degree also at the beginning of the 20th century. Their original discovery was due to the coal mining activities at that time, although, since the seams are generally thin, the mines have not been worked for a long time. Only during the Second World War was an attempt made to mine the coal seams again. One waste heap of this relatively recent activity is now under investigation; heaps from former times are less useful for collecting because the plant bearing sediments have mainly decomposed to a soft grey mud.

A considerable amount of information is available about the waste heap. The coal field and the seams from which it was derived are known, since the original mining plans, with lithological descriptions, have been found in the archives of the Department of Rohstoffgeologie at the Geological Survey (Vienna). Fortunately, those parts of the seams where plants remains were observed have been marked on the maps. In the waste heaps, different types of sediments have been recognized and a correlation of sediment types and plant taxa observed. For example, grey sandstones often contain rhizomes or root-like fossils and Equisetaceae are clearly recognizable. Similarly, Pterophyllum is mainly found in well-bedded shaley clay, as are the ferns. A third type, a very strong sediment with carbonate, includes mainly Asterotheca, Danaeopsis, and Pterophyllum remains.

The main disadvantage of this type of fossil site is that the number (relative abundance) of specimens, which is important for palaeovegetational reconstructions, cannot be properly determined. Fragmentation occurred during mining, during transportation to the waste-heap, during their subsequent weathering and finally during the new excavations. As a result, the number of, for example, Pterophyllum or Nilsonia specimens does not mirror the original number, although counting the basal and apical parts indicates the lowest possible number of specimens. Counting the Equisetaceae and ferns is more complicated and a good method for determining their abundance has not yet been found.

Further disadvantages are that fragmentation and the sometimes rather poor state of preservation may hinder an exact identification. Despite this, cuticles have been taken in many cases and the venation is also often well preserved, contributing to an exact identification.

At this preliminary stage of the investigations, many reliably identified specimens have been collected (several hundreds samples altogether) - suitable for palaeo-ecology reconstructions together with the sedimentological observations. Essentially, all the data are not much poorer in quality than that which can be established from examinations of existing old museum collections from other plant-bearing localities within the Lunz Formation.

Neocalamites asperrimus (Franke) Shen 1990, a morphospecies for Triassic sphenophyte "cortical structures"?

Evelyn Kustatscher1 & Johanna H.A. van Konijnenburg-van Cittert2
1 Evelyn Kustatscher, Naturmuseum Südtirol, Via Bottai 1, 39100 Bolzano, Italy, email Evelyn.Kustatscher@naturmuseum.it
2 Johanna H.A. van Konijnenburg-van Cittert, Laboratory of Palaeobotany and Palynology, Budapestlaan 4, 3584 CD Utrecht and National Natural History Museum "Naturalis", PO Box 9517, 2300 RA Leiden, The Netherlands, e-mail J.H.A.vanKonijnenburg@bio.uu.nl

Recent studies of a large collection of plant fossils from "Thale im Harz" recovered "fragments of skin with slight undulations" described as Equisetites asperrimus by Franke (1936, p. 219-221).

The 25 equisetalean cortex fragments are up to 9 cm long and 7 cm wide and show various coarsely undulating structures.

In 1936 Franke (1936, p. 220-1) created a new species for this material since the cortical surfaces of E. arenaceus (Jaeger) Schenk, (E. latecostatus Muenster) and E. platyodon Brongniart were all known to be smooth. Some specimens from China described by Sze (1956, p. 122) as Neocalamites rugosus Sze showed not only the same "zigzag" feature of the cortex but also vascular bundles and whorls of leaf scars. Shen (1990) considered N. rugosus and E. asperrimus to be conspecific and renamed the material Neocalamites asperrimus (Franke) Shen according to the rules of nomenclature.

Today the correct botanical attribution of these structures is still not clear. Kelber and Hansch (1995, p. 40, figs 68, 70) suggest that the cortical structures were caused by preservation. In this case, according to the examples from China, the species could just be a desiccation structure of Neocalamites meriani (Brongniart) Halle. We can however still not completely exclude that the material from Thale belongings to the other abundant horsetail genus, Equisetites. The Chinese material seems to belong to Neocalamites because of the leaves. Until the botanical affinity has been cleared, we prefer to name the material from Thale Neocalamites asperrimus as proposed by Shen (1990).

Franke, F. (1936). Equisetites asperrimus, ein neuer Equisetit aus dem Keuper Mitteldeutschlands. - Jahrbuch der Preussischen Geologischen Landesanstalt, A, 56: 219-221.
Kelber, K.-P. & Hansch W. (1995). Keuperpflanzen. Die Enträtselung einer über 200 Millionen Jahre alten Flora. - Museo, 11: 1-157.
Shen, G. (1990). Neocalamites rugosus Sze and Equisetites asperrimus Franke are synonymum. - Scientia Geologica Sinica, 7(33): 302-305.
Sze H C. (1956). Mesozoic plants from the Yenchang Formation, Northern Shensi. - Palaeontologia Siniea, New Series A, 5: 1-127 [in Chinese with English abstract].

Taphonomic aspects of the late Early Cretaceous Crato flora (Brazil)

Lutz Kunzmann1, Barbara A.R. Mohr2 & Mary E.C. Bernardes-de-Oliveira3
1 Museum für Mineralogie und Geologie der Staatlichen Naturhistorischen Sammlungen Dresden, Königsbrücker Landstrasse. 159, D-01109 Dresden, Germany (e-mail: lutz.kunzmann@snsd.smwk.sachsen.de).
2 Museum für Naturkunde der Humboldt-Universität Berlin, Institut für Paläontologie, Invalidenstrasse 43, D-10 115 Berlin, Germany.
3 CEPPE - Post-Graduation, Research and Specialization Centre of the University Guarulhos, Praça Tereza Cristina 1, 07023-070, Guarulhos (SP), Brazil and Institute of Geosciences, University of São Paulo, Rua do Lago 562, Cidade Universitária, 05508-080, São Paulo (SP), Brazil.

Fossil plants were studied from the Araripe sedimentary basin, located in the landscape called Chapada do Araripe (interior of NE Brazil). The Cretaceous Santana Group, which includes the Crato, Ipubi, Romualdo and Arajara formations, is the sedimentary expression of the post rift phase of the opening of the Southern Atlantic Ocean. The age of the Crato Formation is currently thought to be late Aptian.

The Crato Formation consists of bedded (plattenkalk) limestone that was deposited in a lacustrine or lagoonal environment developed within the interior basin. The area was in a tropical-equatorial hot (semi-)arid evaporite belt, probably with strongly developed dry seasons and periodical precipitation.

The Crato limestone of light beige to greyish brown color, is mined commercially in the area of Santana do Cariri and is well known for its rich, partly extraordinarily well preserved fauna and flora. The Crato flora comprises about 80 taxa (macroflora), of which 30 or more belong to angiosperms.

Many fossil remains are relatively fragmentary and partly abraded. Therefore, it is assumed that these plants did not grow close to the area of deposition, but in a "hinterland" and the plant parts were probably transported via rivers to the area of deposition. Some plant fossils, however, are also preserved more or less completely and show excellent morphological details. This speaks against long distance transport. It has been suggested that episodic or periodical strong rains with subsequent flooding most likely washed the complete plants to their burial place.

Usually plant material is preserved as compressions, but much of the very brittle fossil plant matter has been lost during the splitting of the limestone, especially matter from the leaves. Most specimens are thus preserved only as light brown impressions on the light yellow-brown limestone slabs. Original tissues are typically replaced by iron oxides, mainly goethite, that preserves in some cases almost all details of the epidermal cell structures of the plant fossils. Cellular details of the epidermis of leaves and axes such as the presence of stomata on different organs or arrangement of non-modified epidermal cells are partly visible under the light microscope. Details of the single elements of the epidermis (stomata, non-modified epidermal cells etc.) can be observed with the SEM. Coalified material is, however, only rarely preserved within the basal part of the Crato Formation.

For more detailed information and references see: Kunzmann, L., Mohr, B. A. R., Bernardes-de-Oliveira, M. E. C. (2007). Novaolindia dubia gen. et sp. nov., an enigmatic seed plant from the Early Cretaceous of northern Gondwana. - Rev. Palaeobot. Palynol. 147: 94-105.

Monospecific "leaf-jams" in the seasonal/ephemeral Hoanib River in the northern Namib (NW Namibia)

Christa-Ch. Hofmann1 & A. Hugh N. Rice2
1 University of Vienna, Department of Palaeontology;
2 University of Vienna, Department of Geodynamics & Sedimentology.

Namibia, an arid to semi-arid country with a yearly rainfall ranging from zero mm in the west to locally 200-300 mm in the northeast, is not a place where one necessarily expects do taphonomical fieldwork for palaeobotany. A common presumption is that plants are relatively uncommon and that, where present, they are small succulents or withered, very dry stuff, which disintegrates with time to dust. However, in northwest Namibia, the Savanna Biome (Bushveld Biome) borders the Namib desert and is dissected by westward flowing ephemeral rivers, typically dry (seasonally fed "rivieres") that support relatively large stands of azonal vegetation. These are, therefore, important for wildlife (elephants, rhinoceros, giraffes, springbok, etc). At Khowarib Gorge, near Sesfontein, the Hoanib River, like many rivers in this area, has a seepage, from which water flows above ground for a couple of kilometres, even during the dry season. This supports a relatively lush vegetation within the gorge, especially on pointbars, and adjacent areas. Mopane trees (Colophospermum mopane) are very abundant in both the zonal vegetation (Mopane woodland or shrub woodland intermingled with a few Terminalia prunoides) and the azonal vegetation. Additional azonal woody species comprise Acacia reficiens, Acacia sp., Combretum wattii, C. imberbe, Cordia sinensis, Faidherbia albida, Hyphaene petersiana (the macalani palm), Salvadora persica and Tamarix usneoides, many of which shed a large portion of their leaves at the beginning of, or during the dry season (approximately April to September). Decomposition of leaf material under such dry conditions is relatively slow and the abscised and withered litter accumulates on the ground, where it is fragmented by trampling (animals) and the wind. During the rainy season, this litter may be washed into the rivieres (drainage valleys).

Within the seepage area of the Hoanib river channel, many longitudinal, densely packed leaf deposits ("leaf-jams": 25-50 cm long, ca.10 cm across) were found. These occur over a ca. 4 m wide by 40 m long stretch in the middle of a left-curving bend, between the still active stream on the outside of the bend and a low sandy "point bar" on the inside. The leaf-jams, which had an 303-069° range in orientations (005-064° range in mean orientations), lay parallel to the channel direction and all at essentially the same elevation above/distance from the then prevailing trickle of water.

The leaves were stacked, essentially vertically, upstream of angular pebbles and small boulders (ca. 5-15cm) or twigs (Tamarix, Colophospermum, unknown) caught between subangular pebbles standing proud of the sediments. Up to the lower third (ca. 5 cm) of the leaf jams were embedded in fluvial sediments (medium coarse sand and silt with a topmost clay lining), with fine sediment also trapped between the parts of the leaves standing proud. Only the bi-pinnate leaves (either complete or broken in half, but rarely fragmented) of Colophospermum mopane (Mopane tree) and, rarely, grass-stalks were found in the jams.

Deposition of the leaf jams must have taken place towards the end of the rainy season when the litter was washed into the channel and the discharge energy was high enough to transport sand and ?waterlogged mopane leaves, but too low for a turbulent flow, which would prohibit the settling and stacking of the leaves. This probably developed at a particular interval (hence their narrow geographic distribution) in the waning flood stage, when the flow energy decreased, giving also the topmost clay lining.

The composition of the leaf-jams begs the question as to why they are monospecific, comprising only mopane leaves? First, leaves of evergreen taxa, (e.g. Boscia, Croton, Ficus, Tamarix, Salvadora), are generally rarely represented in the dry season litter layer. Further, except for Tamarix and Salvadora, these taxa are uncommon in the standing vegetation, so their absence in the leaf jams is understandable. Second, the small leaves of Acacias and Tamarix (which disintegrate into tiny leaflets) and Boscia, Combretum wattii, Commiphora, Faidherbia, Grewia, Terminalia in the litter layer would have been transported further in a waning, low-energy flow than the bigger ones.

However, the absence of the bigger leaved taxa, such as Cordia sinensis, which is deciduous but uncommon in the vegetation, the common evergreen Salvadora persica, or at least the common deciduous Combretum imberbe in the leaf-jams is remarkable. The narrow geographical distribution of the leaf-jams suggests that these leaves have an unsuitable hydrodynamic form and were deposited earlier, on the sandy "point-bar". Essentially, the monospecifity of the leaf-jams resulted from the coincidence of an irregular river bed at the same place as the current was no longer able to transport leaves with the hydrodynamic properties of mopane leaves.

Discussion on the production and fate of charcoals following a heathland and peatland fire in Surrey, UK.

Margaret E. Collinson 1, Andrew C. Scott 1, Vicky Hudspith 1, Rachel Brain 2, David Steart 1, Laura McParland 1 and Sharon Gibbons 1.
1 Department of Earth Sciences, Royal Holloway University of London
2 School of Biological Sciences, University of Plymouth.

As a follow up to our work at Tilford (Scott et al. 2000, Palaeo3, 164, 1-31) we have been tracking the fate of charcoal following a fire in Summer 2006 at nearby Thursley (Surrey, UK). Thursley differs from Tilford in being a protected National Nature Reserve and SSSI with a large area of peatland, including Sphagnum and monocotyledon-dominated bog (especially Molinia, Carex, Scirpus, Eriophorum and Narthecium). This is surrounded by heathland dominated by Calluna, Erica spp. and Ulex, and open woodland dominated by Betula and Pinus. Large tracts of Pteridium occur in open woodland and at edges of the heathland. The fire burnt across all these habitats and all were examined within one month of the fire. Accumulations of charcoals have been collected at intervals since the fire from natural pits (created by tree loss) and from gulley wash. In addition short cores have been taken through the peat-forming areas. Experimental charring work has also been undertaken on peat and selected plant material.

We present a series of observations as a basis for discussion of the production and fate of charcoal and its implications for the fossil record.

Sphagnum was dried and in places scorched by the fire but hardly any fully charred Sphagnum was encountered on the site.

Short cores from the peats do not show a charred surface peat layer nor obvious discrete sub-surface charred layers that would be expected if former fires had burned the peat surface. Experimental work shows that charred peat would be recogniseable, therefore, the peat itself did not burn.

Molinia was extensively charred, some charring even resulted in detached tussocks, but charred leaves were extremely fragile.

Outside the peatland the dominant plants on the reserve all yielded charcoal but there was very little Pteridium (fern) charcoal even amongst former stands and this fern charred in an unexpected manner.

No Pteridium charcoals have been found in the accumulations.

No charcoals from any of the bog plants have yet been recognised in the accumulations.

The accumulations are dominated by Calluna charcoals.

Leafy shoots of Calluna are fairly common in the accumulations but leafy shoots of Erica and Ulex are extremely rare or absent.

Thick (>20cm) accumulations of fine (mostly <4mm) charcoal resulted from gulley wash down slope.

Where thick charcoal accumulations were stable their surfaces became colonised, the following Summer, with extensive bryophyte (mosses and liverworts) cover; a community not normally present in those areas of the reserve.

Acknowledgements: Natural England (Simon Nobes and James Giles) for permission to study and sample at Thursley; The Nuffield Foundation for a student bursary to fund VH. The Leverhulme Trust for a Research grant (to MEC & ACS) funding DS.

List of Participants

Otto Cichocki, VIAS, Institut für Paläontologie, Geozentrum, Universität Wien, Althanstrasse 14, A-1090 Wien, Austria. Tel. 00-43-1.4277.40308, e-mail: otto.cichocki@univie.ac.at

Margaret E. Collinson, Geology Department, Royal Holloway University of London, Egham, Surrey, TW20 0EX, England. Tel. 00-44-1784.443607. e-mail: m.collinson@gl.rhul.ac.uk

Helen Craggs, Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, Buckinghamshire, England. Tel. 00-44-1628.637899. e-mail: H.J.Craggs@open.ac.uk

Ilse Draxler, Geologische Bundesanstalt, Neulinggasse 38, A-1030 Vienna, Austria. Tel. 00-43-1.7125674-251, e-mail: ilse.draxler@geologie.ac.at

David K. Ferguson, Institut für Paläontologie, Geozentrum, Universität Wien, Althanstrasse 14, A-1090 Wien, Austria. Tel. 00-43-1.4277.53565, e-mail: david.kay.ferguson@univie.ac.at

Thilo Fischer, Dept. Pflanzenwissenschaften, Lehrstuhl für Zierpflanzenbau und Gartenbauliche Pflanzenzüchtung, Technische Universität München, Am Hochanger 4, D-85350 Freising, Germany. Tel. 00-49-8161.713419, e-mail: thilo.fischer@wzw.tum.de

Karin Frencl, Institut für Paläontologie, Geozentrum, Universität Wien, Althanstrasse 14, A-1090 Wien, Austria, e-mail: k.frencl@gmx.at

Carole T. Gee, Institut für Paläontologie, Universität Bonn, Nussallee 8, D-53115 Bonn, Germany. Tel. 00-49-228.733063, e-mail: cgee@uni-bonn.de

Wolfgang Göschl, Institut für Paläontologie, Geozentrum, Universität Wien, Althanstrasse 14, A-1090 Wien, Austria. Tel. (mobile) 0699-1923.6913, e-mail: a8201826@imag.univie.ac.at

Christa-Charlotte Hofmann, Institut für Paläontologie, Geozentrum, Universität Wien, Althanstrasse 14, A-1090 Wien, Austria. Tel. 00-43-1.4277.53574, e-mail: christa.hofmann@univie.ac.at

Andrea Kern, Institut für Paläontologie, Geozentrum, Universität Wien, Althanstrasse 14, A-1090 Wien, Austria, e-mail: kern.andrea@inode.at

Johanna H. A. van Konijnenburg-van Cittert, Laboratory of Palaeobotany and Palynology, Budapestlaan 4, NL-3584 Utrecht. Tel. 00-31-30.2532635, e-mail: j.h.a.vankonijnenburg@uu.nl & National Natural History Museum "Naturalis", PO Box 9517, NL-2300 RA Leiden, The Netherlands, e-mail: konijnenburg@naturalis.nl

Lutz Kunzmann, Museum für Mineralogie und Geologie, Staatliche Naturhistorische Sammlungen Dresden, Königsbrücker Landstrasse 159, D-01109 Dresden, Germany. Tel. 00-49-351.89.26406, e-mail: lutz.kunzmann@snsd.smwk.sachsen.de

Evelyn Kustatscher, Naturmuseum Südtirol, Bindergasse 1, I-39100 Bozen, Italy. Tel. 00-39-0471.412963, e-mail: Evelyn.Kustatscher@naturmuseum.it

Barbara Meller, Institut für Paläontologie, Geozentrum, Universität Wien, Althanstrasse 14, A-1090 Wien, Austria. Tel. 00-43-1.4277.53584, e-mail: barbara.meller@univie.ac.at

Robert A. Spicer, Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, Buckinghamshire, England. Tel. 00-44-1908.652887, e-mail: R.A.Spicer@open.ac.uk

Norbert Vávra, Institut für Paläontologie, Geozentrum, Universität Wien, Althanstrasse 14, A-1090 Wien, Austria. Tel. 00-43-1.4277.53550, e-mail: norbert.vavra@univie.ac.at

Reinhard Zetter, Institut für Paläontologie, Geozentrum, Universität Wien, Althanstrasse 14, A-1090 Wien, Austria. Tel. 00-43-1.4277.53572, e-mail: reinhard.zetter@univie.ac.at

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