The Possible Pollen Cone of the Late Triassic Conifer Heidiphyllum/Telemachus (Voltziales) From Antarctica

This is the publisher's version, which is being used with permission. The original article may be found at: http://dx.doi.org/10.1017/S0954102011000241Fossil leaves of the Voltziales, an ancestral group of conifers, rank among the most common plant fossils in the Triassic of Gondwana. Even though the foliage taxon Heidiphyllum has been known for more than 150 years, our knowledge of the reproductive organs of these conifers still remains very incomplete. Seed cones assigned to Telemachus have become increasingly well understood in recent decades, but the pollen cones belonging to these Mesozoic conifers are rare. In this contribution we describe the first compression material of a voltzialean pollen cone from Upper Triassic strata of the Transantarctic Mountains. The cone can be assigned to Switzianthus Anderson & Anderson, a genus that was previously assumed to belong to an enigmatic group of pteridosperms from the Triassic Molteno Formation of South Africa. The similarities of cuticle and pollen morphology, together with co-occurrence at all known localities, indicate that Switzianthus most probably represents the pollen organ of the ubiquitous Heidiphyllum/Telemachus plant

Fossilized spermatozoa preserved in a 50-Myr-old annelid cocoon from Antarctica

The origin and evolution of clitellate annelids-earthworms, leeches and their relatives-is poorly understood, partly because body fossils of these delicate organisms are exceedingly rare. The distinctive egg cases (cocoons) of Clitellata, however, are relatively common in the fossil record, although their potential for phylogenetic studies has remained largely unexplored. Here, we report the remarkable discovery of fossilized spermatozoa preserved within the secreted wall layers of a 50-Myr-old clitellate cocoon from Antarctica, representing the oldest fossil animal sperm yet known. Sperm characters are highly informative for the classification of extant Annelida. The Antarctic fossil spermatozoa have several features that point to affinities with the peculiar, leech-like 'crayfish worms' (Branchiobdellida). We anticipate that systematic surveys of cocoon fossils coupled with advances in non-destructive analytical methods may open a new window into the evolution of minute, soft-bodied life forms that are otherwise only rarely observed in the fossil record.Facultad de Ciencias Naturales y Muse

Fossil clitellate annelid cocoons and their microbiological inclusions from the Eocene of Seymour Island, Antarctica

Clitellate annelids have a meagre body fossil record but they secrete proteinaceous cocoons for the protection of eggs that, after hardening, are readily fossilized and offer a largely untapped resource for assessing the evolutionary history of this group. We describe three species of clitellate cocoons (viz., Burejospermum seymourense sp. nov., B. punctatum sp. nov. and Pegmatothylakos manumii gen. et sp. nov.) from the lower Eocene La Meseta Formation, Seymour Island, Antarctica. The cocoons probably derive from continental settings and were transported to, and preserved within, nearshore marine to estuarine environments. The cocoons provide the first evidence of commensal or parasitic relationships in the Eocene continental ecosystemsof Antarctica. Moreover, numerous micro-organisms and the oldest fossilizedexamples of animal spermatozoa are preserved as moulds within the consolidatedwalls of the cocoons. Fossil annelid cocoons offer potential for enhanced palaeoenvironmental interpretation of sediments, correlation between continental and shallowmarine strata, and improved understanding of the development of clitellate annelid reproductive traits and the evolutionary history of soft-bodied micro-organisms in general.Facultad de Ciencias Naturales y Muse

Macrofossil Evidence For Pleuromeialean Lycophytes From the Triassic of Antarctica

This is the publisher's version, which is also available electronically from: http://dx.doi.org/10.4202/app.2010.0022Triassic microfloras from Antarctica contain abundant lycophyte spores. However, macrofossils of this group of plants are missing, and thus the precise affinities of the spore producers remain unknown. Macrofossil remains of a pleuro− meialean lycophyte, including an incomplete strobilus, isolated sporophylls and sporangia, as well as abundant mega− spores, occur on a single rock sample from the central Transantarctic Mountains. Also occurring on the same surface is Mesenteriophyllum serratum, a strap−shaped leaf morphotype of uncertain affinity previously known only from the Kyrgyz Republic and the Taimyr Peninsula. The leaves display alternating transverse ridges and depressions that are sim− ilar to structures seen in compressed leaves of various isoetalean lycophytes. Leaf morphology and anatomy, together with the close association of the other lycophyte remains, suggest that M. serratum represents a pleuromeialean lycophyte leaf, which was part of the same plant that produced the sporophylls and sporangia. Sedimentological data indicate that this lycophyte inhabited a swampy, probably coal−forming overbank environment, which contrasts with the assumed xero− to halophytic habit of many other pleuromeialean lycophytes

Fossil clitellate annelid cocoons and their microbiological inclusions from the Eocene of Seymour Island, Antarctica

Clitellate annelids have a meagre body fossil record but they secrete proteinaceous cocoons for the protection of eggs that, after hardening, are readily fossilized and offer a largely untapped resource for assessing the evolutionary history of this group. We describe three species of clitellate cocoons (viz., Burejospermum seymourense sp. nov., B. punctatum sp. nov. and Pegmatothylakos manumii gen. et sp. nov.) from the lower Eocene La Meseta Formation, Seymour Island, Antarctica. The cocoons probably derive from continental settings and were transported to, and preserved within, nearshore marine to estuarine environments. The cocoons provide the first evidence of commensal or parasitic relationships in the Eocene continental ecosystemsof Antarctica. Moreover, numerous micro-organisms and the oldest fossilizedexamples of animal spermatozoa are preserved as moulds within the consolidatedwalls of the cocoons. Fossil annelid cocoons offer potential for enhanced palaeoenvironmental interpretation of sediments, correlation between continental and shallowmarine strata, and improved understanding of the development of clitellate annelid reproductive traits and the evolutionary history of soft-bodied micro-organisms in general.Facultad de Ciencias Naturales y Muse

Triassic Leech Cocoon From Antarctica Contains Fossil Bell Animal

This is the publisher's version of this article, which has been shared with permission. The article is also available from: http://dx.doi.org/10.1073/pnas.1218879109Our understanding of the evolution of life on Earth is limited by the imperfection of the fossil record. One reason for this imperfect record is that organisms without hard parts, such as bones, shells, and wood, have a very low potential to enter the fossil record. Occasionally, however, exceptional fossil deposits that preserve soft-bodied organisms provide a rare glimpse of the true biodiversity during past periods of Earth history. We here present an extraordinary find of a fossil ciliate that is encased inside the wall layer of a more than 200 Ma leech cocoon from Antarctica. The microfossil consists of a helically contractile stalk that attaches to a main body with a peristomial feeding apparatus and a large Cshaped macronucleus. It agrees in every aspect with the living bell animals, such as Vorticella. Vorticellids and similar peritrichs are vital constituents of aquatic ecosystems worldwide, but so far have lacked any fossil record. This discovery offers a glimpse of ancient soft-bodied protozoan biotas, and also highlights the potential of clitellate cocoons as microscopic “conservation traps” comparable to amber

Systematics and Paleoecology of a New Peltaspermalean Seed Fern From the Triassic Polar Vegetation of Gondwana

This is the publisher's version, which has been shared with permission. The original version may be found at: http://dx.doi.org/10.1017/S0954102011000241A new Triassic seed fern is described on the basis of a large collection of well-preserved plant compressions from the Upper Triassic of Mt. Falla, Queen Alexandra Range, central Transantarctic Mountains. The foliage is simple entire-margined to pinnatifid to partly pinnate and is assigned to Dejerseya lobata (Jones et de Jersey) Herbst emend. nov. Associated with these leaves occur two new reproductive structures. The ovulate organ Matatiella dejerseyi sp. nov. is a lax, conelike structure with primarily shield-shaped megasporophylls that are dissected into three to four narrow lobes, each bearing a single recurved, naked ovule. The pollen organ Townrovia polaris sp. nov. consists of a slender axis arising from a covered reproductive bud, bearing pinnately arranged, stalked, elongate receptacles each with ;20 unilocular, clavate pollen sacs; the pollen is bisaccate nontaeniate with an irregular longitudinal sulcus and coarse saccus endoreticulations, corresponding to the dispersed pollen Falcisporites australis. Similar pollen grains occur in the micropylar canals of seed cuticles of M. dejerseyi. Co-occurrence data indicate that the three taxa are probably different organs from one plant species. This new seed fern is assigned to the Matatiellaceae, which we place into the Peltaspermales because of structural similarities with vegetative and reproductive organs of other peltaspermalean seed ferns. It appears that several Triassic Gondwanan plant fossil taxa of currently uncertain affinities—such as Pachydermophyllum, Linguifolium, Carpolithus mackayi, and Andersonia—may belong to the Matatiellaceae as well. We suggest that the matatiellacean peltasperms were opportunistic, early successional plants that were particularly successful in colonizing stressed wetland environments in polar latitudes during the Triassic

A reappraisal of Mississippian (Tournaisian and Visean) adpression floras from central and northwestern Europe

Mississippian plant fossils are generally rare, and in central and northwestern Europe especially Tournaisian to middle Visean fossil floras are restricted to isolated occurrences. While sphenophytes and lycophytes generally are represented by only a few widespread and long-ranging taxa such as Archaeocalamites radiatus, Sphenophyllum tenerrimum and several species of Lepidodendropsis and Lepidodendron, Visean floras in particular show a remarkably high diversity of fern-like foliage, including filiform types (Rhodea, Diplotmema), forms with bipartite fronds (Sphenopteridium, Diplopteridium, Spathulopteris, Archaeopteridium), others with monopodial, pinnate fronds (Anisopteris, Fryopsis) and still others characterized by several-times pinnate fronds (e.g., Adiantites, Triphyllopteris, Sphenopteris, Neuropteris). Most of these leaf types have been interpreted as belonging to early seed ferns, whereas true ferns seem to have been rare or lacking in impression/compression floras. In the upper Visean, two types of plant assemblages can be distinguished, i.e., the northern Kohlenkalk-type and the south-eastern Kulm-type assemblage. Although several compression/impression taxa have been revised in recent years to provide a more uniform classification, additional parameters such as different modes of preservation and imprecise information on stratigraphic age hamper detailed interregional comparisons of Mississippian floras.Pflanzenfossilien aus dem Mississippium sind generell selten. Floren aus dem Tournaisium bis Mittel-Viseum hat man in Zentral- und Nordwesteuropa nur in wenigen isolierten Lokalitäten gefunden. Diese Floren sind von Sphenophyten und Lycophyten (z.B. Archaeocalamites radiatus, Sphenophyllum tenerrimum sowie Taxa aus den Gattungen Lepidodendropsis und Lepidodendron) dominiert, welche alle eine weite geographische Verbreitung und lange geologische Reichweite aufweisen. Demgegenüber weisen die Floren des jüngeren Viseum eine bemerkenswerte Diversität an Pteridophyllen auf. Neben filiformen Wedeln (Rhodea, Diplotmema) kennt man aus diesen Floren unterschiedliche Typen einfach gegabelter (Sphenopteridium, Diplopteridium, Spathulopteris, Archaeopteridium) sowie einfach (Anisopteris, Fryopsis) und mehrfach gefiederter Wedel (e.g., Adiantites, Triphyllopteris, Sphenopteris, Neuropteris). Der überwiegende Teil dieser Wedel wird den frühen Samenfarnen zugeordnet; Nachweise von echten Farnen sind ausgesprochen selten. Im oberen Viseum können zwei unterschiedliche Pflanzenassoziationen unterschieden werden: eine nördliche Kohlenkalk-Assoziation und eine südöstliche Kulm-Assoziation. Obwohl mehrere Pflanzentaxa des Mississippiums in Europa in den vergangenen Jahren revidiert worden sind, bleiben doch überregionale Vergleiche sowie die Erstellung einer einheitlichen Klassifikation durch die z.T. großen Unterschiede in der Erhaltung der Fossilien aus den einzelnen Fundpunkten sowie durch Probleme bei der Bestimmung des exakten stratigraphischen Alters der jeweiligen Fundschichten schwierig

Fossilized spermatozoa preserved in a 50-Myr-old annelid cocoon from Antarctica

The origin and evolution of clitellate annelids-earthworms, leeches and their relatives-is poorly understood, partly because body fossils of these delicate organisms are exceedingly rare. The distinctive egg cases (cocoons) of Clitellata, however, are relatively common in the fossil record, although their potential for phylogenetic studies has remained largely unexplored. Here, we report the remarkable discovery of fossilized spermatozoa preserved within the secreted wall layers of a 50-Myr-old clitellate cocoon from Antarctica, representing the oldest fossil animal sperm yet known. Sperm characters are highly informative for the classification of extant Annelida. The Antarctic fossil spermatozoa have several features that point to affinities with the peculiar, leech-like 'crayfish worms' (Branchiobdellida). We anticipate that systematic surveys of cocoon fossils coupled with advances in non-destructive analytical methods may open a new window into the evolution of minute, soft-bodied life forms that are otherwise only rarely observed in the fossil record.Facultad de Ciencias Naturales y Muse

Response to Comment on "Dying in the Sun: Direct evidence for elevated UV-B radiation at the end-Permian mass extinction"

Seddon and Zimmermann have raised questions about the evidence for increased UV-B flux across the end-Permian mass extinction (EPME) that was presented in our recent study, specifically regarding the measurement of UV-B-absorbing compound (UAC) levels in fossil pollen. We respond to these points, arguing that the comparison of FTIR spectra of >250 million-year-old Permian fossil pollen with ~700-year-old subfossil pollen is not valid and that negligible nonrandom interference derived from water vapor fluctuations during data generation cannot coincidentally produce a substantial UAC peak during the EPME. Furthermore, we refute the suggestion that the measured aromatic peak at 1600 cm-1 could have been influenced by diagenetic products from other organic constituents of pollen. The most productive route forward will be to generate sporomorph geochemical data from additional Permian-Triassic boundary sections to test the results put forward in our study