Cyrille Prestianni

A Simple Type of Wood in Two Early Devonian Plants

The earliest evolution of wood occurred in plants of surprisingly small stature. The advent of wood (secondary xylem) is a major event of the Paleozoic Era, facilitating the evolution of large perennial plants. The first steps of wood evolution are unknown. We describe two small Early Devonian (407 to 397 million years ago) plants with secondary xylem including simple rays. Their wood currently represents the earliest evidence of secondary growth in plants. The small size of the plants and the presence of thick-walled cortical cells confirm that wood early evolution was driven by hydraulic constraints rather than by the necessity of mechanical support for increasing height. The plants described here are most probably precursors of lignophytes.

A complete insect from the Late Devonian period

After terrestrialization, the diversification of arthropods and vertebrates is thought to have occurred in two distinct phases, the first between the Silurian and the Frasnian stages (Late Devonian period) (425–385 million years (Myr) ago), and the second characterized by the emergence of numerous new major taxa, during the Late Carboniferous period (after 345 Myr ago). These two diversification periods bracket the depauperate vertebrate Romer’s gap (360–345 Myr ago) and arthropod gap (385–325 Myr ago), which could be due to preservational artefact. Although a recent molecular dating has given an age of 390 Myr for the Holometabola, the record of hexapods during the Early–Middle Devonian (411.5–391 Myr ago, Pragian to Givetian stages) is exceptionally sparse and based on fragmentary remains, which hinders the timing of this diversification. Indeed, although Devonian Archaeognatha are problematic, the Pragian of Scotland has given some Collembola and the incomplete insect Rhyniognatha, with its diagnostic dicondylic, metapterygotan mandibles. The oldest, definitively winged insects are from the Serpukhovian stage (latest Early Carboniferous period). Here we report the first complete Late Devonian insect, which was probably a terrestrial species. Its ‘orthopteroid’ mandibles are of an omnivorous type, clearly not modified for a solely carnivorous diet. This discovery narrows the 45-Myr gap in the fossil record of Hexapoda, and demonstrates further a first Devonian phase of diversification for the Hexapoda, as in vertebrates, and suggests that the Pterygota diversified before and during Romer’s gap.

Early seed plant radiation : an ecological hypothesis.

Abstract The earliest steps of seed plant evolution have been extensively studied during the past 25 years. There is a growing body of evidence indicating that the first major spermatophyte radiation occurred during the Late Devonian. At least fourteen Late Devonian species are now recognized, and our knowledge of the diversity of those early seed plants has dramatically increased. Five morphotypes of seeds have been defined, mostly based on cupule morphology and on the number and degree of fusion of the integumentary lobes. In this paper, we critically discuss the abundant environmental information in order to characterize the environment in which this radiation occurred. Sedimentological information indicates that seed plants evolved in disturbed environments. It is suggested that early seed plants thrived in the shade of the dominating Archaeopteris, and that their evolution was canalized by this strong biotic pressure. We also confirm the previous suggestion that the variability of seed morphotypes can be explained by the weak abiotic selective pressure that existed in the Archaeopteris understory.

Early diversification of seeds and seed-like structures

The seed habit is one of the most important evolutionary acquisition in plant evolution. It allowed colonisation of new ecological niches, leading to a level of diversification never observed before. The seed habit involves occurrence of a single functional megaspore within an indehiscent megasporangium (nucellus), development of an endosporic megagametophyte, enclosure of the nucellus by an integument, and capture of pollen before dispersal from the sporophyte.

Garrouste et al. reply

replying to T. Hörnschemeyer et al. Nature 494, 10.1038/nature11887 (2013)Since the nineteenth century, Devonian insects have repeatedly proven to be something else, the sole exception being Rhyniognatha. Recently the Devonian insect Strudiella devonica has been denied by Hörnschemeyer et al., who could not “confirm the presence of a mandible or of mandibular teeth”.

Stratigraphy and depositional environments of the Late Famennian (Late Devonian) of Southern Belgium and characterization of the Strud locality

The Famennian (Upper Devonian, c . 372 to 359 Ma) strata of Belgium have recently received much attention after the discoveries of early tetrapod remains and outstandingly preserved continental arthropods. The Strud locality has yielded a diverse flora and fauna including seed-plants, tetrapods, various placoderm, actinopterygian, acanthodian and sarcopterygian fishes, crustaceans (anostracans, notostracans, conchostracans and decapods) and a putative complete insect. This fossil assemblage is one of the oldest continental – probably fresh-water – ecosystems with a considerable vertebrate and invertebrate diversity. The study of the palaeoenvironment of the Strud locality is crucial because it records one of the earliest and most important phases of tetrapod evolution that took place after their emergence but before their terrestrialization. It raises the question of environmental and ecological conditions for the Devonian aquatic ecosystem and the selection pressures occurring at the onset of tetrapod terrestrialization. The present study characterized the fluvial facies of the Upper Famennian sedimentary rocks of Strud and the surrounding areas. The exceptional preservation of arthropods and plants in the main fossiliferous layers is explained by rapid burial in the fine-grained sediment of the quiet and confined flood plain environment. Newly investigated fossiliferous sections in the Meuse–Samson area led to the description and correlation of key sections (Strud, Wierde and Jausse sections, complemented by the less continuous Haltinne, Huy and Coutisse sections). Moreover, the investigated sections allowed a review of the age of the fossiliferous horizon, which is now definitely considered to be Late Famennian in age.

A New Species of Groenlandaspis Heintz, 1932 (Placodermi, Arthrodira), from the Famennian (Late Devonian) of Belgium

ABSTRACT A new species of the phlyctaeniid arthrodire genus Groenlandaspis from the upper Famennian of Belgium is described. The remains of Groenlandaspis potyi, sp. nov., consist of dissociated thoracic armor elements, but the specimen designated to be the holotype displays the median dorsal, anterior, and posterior dorsolateral plates in articulation. Though incomplete, the new species is characterized by an equilateral triangle-shaped median dorsal plate, a protruding posterodorsal apron of the posterior dorsolateral plate behind the overlap area for the median dorsal plate, and an overall lack of ornamentation. Groenlandaspis potyi, sp. nov., constitutes the second occurrence of a Groenlandaspis species in continental Europe after the description of Groenlandaspis thorezi from upper Famennian quarries of Belgium. Another probable new species of Groenlandaspis is also described, though of unknown locality and horizon; it can, however, be deduced to be from the upper Famennian of Belgium without more precision. Together with some unpublished material of groenlandaspidids from the Famennian tetrapod-bearing locality of Strud, this material highlights the richness of Groenlandaspididae diversity in Belgium. The discovery of Groenlandaspis potyi, sp. nov., in Belgium reinforces the Famennian global distribution of this genus during this period. Also, because these organisms have been considered as nonmarine indicators, this material is another argument pleading for close relationships between Euramerica and Gondwana around the Frasnian—Famennian boundary.

Thorezia vezerensisgen. et sp. nov., a new seed plant with multiovulate cupules from the Late Devonian of Belgium

The multiovulate cupule of a new spermatophyte, Thorezia vezerensisgen. et sp. nov., is described from the Late Devonian aged sediments from Trooz Quarry in Belgium. In gross morphology, it conforms to the Moresnetia morphotype and has a cupule that is composed of four independent quarters that each dichotomises three times. Each cupule quarter contains one single ovoid preovule with a long pedicel and an integument that has small apical teeth surrounding a rudimentary micropyle. Morphological variability in the materials examined is interpreted as being related to preovule maturity, and from this a good understanding of the ontogenetic development from preceding dispersal has been developed. Up to now, 17 spermatophyte species have been described, 11 of which come from eastern Laurussia. This diversity in eastern Laurussia contrasts strongly with the low diversity characterizing contemporaneous floras from other phytogeographical areas. We suggest here that the arid climatic conditions prevailing in eastern Laurussia favoured the development of diverse spermatophyte communities and contributed to reduced diversity and abundance of contemporaneous free-sporing plant diversity.

MORPHYLL: A a database of fossil leaves and their morphological traits

Morphometric characters of fossil leaves such as size and shape are important and widely used sources for reconstructing palaeoenvironments. Various tools, including CLAMP or Leaf Margin Analysis, utilize leaf traits as input parameters for estimating palaeoclimate, mostly based on correlations between traits and climate parameters of extant plants. During the last few years, the scope of information extracted from the morphology of fossil leaves has been further expanded by including leaf economics, which describe correlations between functional leaf traits and ecological strategies. The amount and quality of available data are essential for a successful palaeoecological analysis utilizing leaf traits. Here, the database MORPHYLL is described. This database is devised to offer a web-based resource for fossil leaf trait data. For this purpose, fossil leaves from various collections were digitized and morphometric traits extracted from leaf outlines. Besides metadata such as accession number, repository, fossil site or taxonomic information (for identified specimens), MORPHYLL offers queries for several morphometric parameters and derived ecophysiological traits (e.g., leaf mass per area). Currently, the database contains data from about 6000 fossil leaves from sites in Central Europe, spanning almost the entire Paleogene and part of the early Neogene. The application potential of the database is demonstrated by conducting some exemplary analyses of leaf traits for the Paleocene, Eocene and Oligocene, with the results indicating changes of mean leaf traits through time. For example, the results show leaf mass per area to peak during the Eocene, which is in accordance with general climate development during the Paleogene. Christopher Traiser. State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. traiser@smns-bw.de Anita Roth-Nebelsick. State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. Traiser, Christopher, Roth-Nebelsick, Anita, Grein, Michaela, Kovar-Eder, Johanna, Kunzmann, Lutz, Moraweck, Karolin, Lange, Jörg, Kvaček, Jiří, Neinhuis, Christoph, Folie, Annelise, De Franceschi, Dario, Kroh, Andreas, Prestianni, Cyrille, Poschmann, Markus, and Wuttke, Michael. 2018. MORPHYLL: A database of fossil leaves and their morphological traits. Palaeontologia Electronica 21.1.1T: 117 https://doi.org/10.26879/773 palaeo-electronica.org/content/2018/2114-database-of-fossil-leaves Copyright: January 2018 Palaeontology Association. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ TRAISER ET AL.: DATABASE OF FOSSIL LEAVES anita.rothnebelsick@smns-bw.de Michaela Grein. State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. michaela.grein@smns-bw.de; present address: Übersee-Museum Bremen, Bahnhofsplatz 13, 28195 Bremen, Germany. m.grein@uebersee-museum.de Johanna Kovar-Eder. State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. johanna.eder@smns-bw.de Lutz Kunzmann, Senckenberg Natural History Collections Dresden, Königsbrücker Landstr. 159, 01109 Dresden, Germany. lutz.kunzmann@senckenberg.de Karolin Moraweck. Senckenberg Natural History Collections Dresden, Königsbrücker Landstr. 159, 01109 Dresden, Germany. karolin.moraweck@senckenberg.de Jörg Lange. State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. joerg.lange@smns-bw.de Jiří Kvaček. National Museum Prague, Václavské náměsti 68, 115 79 Prague 1, Czech Republic. jiri.kvacek@nm.cz Christoph Neinhuis. Technische Universität Dresden, Institute for Botany, Zellescher Weg 20b, 01217 Dresden, Germany. christoph.neinhuis@tu-dresden.de Annelise Folie. Royal Belgian Institute of Natural Sciences, rue Vautier 29, 1000 Brussels, Belgium. afolie@naturalsciences.be Dario De Franceschi. CR2P-Sorbonne-Universités, CP38, 57 rue Cuvier, 75231 Paris, France. dario.defranceschi@mnhn.fr Andreas Kroh. Naturhistorisches Museum Wien, Burgring 7, 1010 Vienna, Austria. andreas.kroh@nhmwien.ac.at Cyrille Prestianni. Royal Belgian Institute of Natural Sciences, rue Vautier 29, 1000 Brussels, Belgium. cprestianni@naturalsciences.be Markus Poschmann. Generaldirektion Kulturelles Erbe RLP, Direktion Landesarchäologie / Erdgeschichte, Niederberger Höhe 1, 56077 Koblenz, Germany. markus.poschmann@gdke.rlp.de Michael Wuttke. Senckenberg Research Institute, Senckenberganlage 25, 60325 Frankfurt am Main, Germany. michael.wuttke@senckenberg.de

The Early Carboniferous progymnosperm Protopitys: new data on vegetative and fertile structures, and on its geographic and stratigraphic distribution

We review progress made during the last 25 years in our understanding of the Protopityales, Early Carboniferous plants belonging to the extinct group of the progymnosperms. Recent studies support previous observations that the only genus of this order, Protopitys, included large arborescent plant with trunks up to 1 m in diameter. All branch orders had an oval eustele, secondary xylem with small rays and tracheid pitting ranging from circular bordered to scalariform bordered, and vascular traces to lateral appendages emitted in an alternate to subopposite distichous arrangement. Leaf morphology remains unknown. New material also confirms that fertile organs of Protopitys consist of branching systems bearing elongated sporangia terminally. Spores have a perispore and range in two size groups, which has been interpreted as a primitive stage of heterospory. The dense wood and fertile parts of Protopitys are comparable to those of the aneurophytalean progymnosperms of the Devonian, but Protopitys is distinct by its eustelic primary vascular system, and its affinities are still uncertain. The genus is now documented from at least nine localities in Europe, North America and Australia. Recent discoveries also indicate that it was present through the whole Mississippian, from the middle Tournaisian to the Serpukhovian.