Time filter

Source Type

Wappler T.,Steinmann Institute for Geology
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010

Insects form an important part of modern terrestrial ecosystems, but while their body remains are rare in the fossil record, their trace fossils, such as feeding damage, are more common. Studies of insect herbivory on fossil leaves can provide key information for an ecological understanding of disturbance and biotic response in deep time, such as the response of insect damage frequency and diversity to changing vegetation and climate. In this contribution, I provide the first, high-resolution study documenting insect damage of fossil leaves that indicate the reaction of insect herbivores to changing regional climates and vegetation during the latest Paleogene in Europe. Insect damage censuses were conducted at six stratigraphic levels ranging in age from 27 to 23 Ma in the Siebengebirge area near Bonn, Germany. A total of 3122 fossil angiosperm leaves pertaining to 135 species were examined for the presence or absence of insect damage types (DTs); fiftynine damage types were recorded. The most parsimonious explanation for the trends observed in this study is that the fossil insect damage represents a regional response to global environmental changes. © 2010 Elsevier B.V. All rights reserved.

de Buffrenil V.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments | Clarac F.,CNRS Institute of Earth Sciences | Canoville A.,Steinmann Institute for Geology | Laurin M.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments
Journal of Morphology | Year: 2016

Bone ornamentation, in the form of rounded pits framed by a network of ridges, is a frequent feature among a great diversity of gnathostome taxa. However, the basic osteogenic processes controlling the differentiation and development of these reliefs remain controversial. The present study is a broad comparative survey of this question with the classical methods used in hard tissue histology and paleohistology. Distinct processes, unevenly distributed among taxa, are involved in the creation and growth of pits and ridges. The simplest one is mere differential growth between pit bottom (slow growth) and ridge top (faster growth). The involvement of several complex remodeling processes, with the local succession of resorption and reconstruction cycles, is frequent and occurs in all major gnathostome clades. Some broad, inclusive clades (e.g., Temnospondyli) display consistency in the mechanisms controlling ornamentation, whereas other clades (e.g., Actinopterygii) are characterized by the diversity of the mechanisms involved. If osteogenic mechanisms are taken into account, bone ornamentation should be considered as a character extremely prone to homoplasy. Maximum likelihood (ML) optimizations reveal that the plesiomorphic mechanism creating ornamentation is differential apposition rate over pits (slow growth) and ridges (faster growth). In some taxas e.g., temnospondyls vs lissamphibians or pseudosuchians, bone ornamentation is likely to be a homoplastic feature due to a convergence process driven by similar selective pressures. ML models of character evolution suggest that the presence of resorption in the development of ornamentation may be selectively advantageous, although support for this conclusion is only moderate. © 2016 Wiley Periodicals, Inc.

Kagan E.,Hebrew University of Jerusalem | Kagan E.,Geological Survey of Israel | Stein M.,Geological Survey of Israel | Agnon A.,Hebrew University of Jerusalem | And 3 more authors.
Journal of Geophysical Research: Solid Earth | Year: 2011

A comprehensive multisite paleoseismic archive of the late Holocene Dead Sea basin (past 2500 years) is established by constructing two age-depth chronological models of two sedimentary sections exposed at the retreating shores of the modern Dead Sea. Two new paleoseismic study sites studied are the Ein Feshkha Nature Reserve outcrop located at the northern part of the basin and close to an active underwater transverse fault and the east Ze'elim Gully outcrop at the southern part of the basin. Age-depth regression models are calculated for these sections based on atmospheric radiocarbon ages of short-lived organic debris calibrated with a Bayesian model. The uncertainties on individual model ages are smaller than 100 years. The new chronological records are compared to a laminae-counting study of the Ein Gedi core (Migowski et al., 2004) located at the central Dead Sea basin. The Ein Feshkha outcrop yielded the largest number of seismites in the studied time interval (n = 52), while lower numbers of seismites are recovered from the Ze'elim outcrop and Ein Gedi core (n = 15 and 36, respectively). The seismites show no strong dependence on the limnological-sedimentological conditions in the particular sampling sites (they coappear in both shallow and deep water environments and in different sedimentary facies). During time intervals when the chronologies are comparable it appears that the number of seismites is significantly larger in the northern part of the basin (Ein Gedi and Ein Feshkha). Seismic quiescence intervals are apparent at all three sites from 2nd-4th century A.D. and at 500-150 B.C. at Ze'elim and Ein Gedi. Several synchronous seismites appear in all sections (termed here the intrabasin seismites (IBS)). Among them: 1927, 1293, 1202/1212, 749, 551, 419, and 33 A.D. and 31 and mid-2nd century B.C. The recurrence time of the IBS from the 2nd century B.C. to the 14th century A.D. is ∼200 years, compared with ∼100 years for all earthquakes. On a diagram of epicentral distance versus magnitude, historic earthquakes that are correlated with IBS plot in a field of high local intensity. The farther and stronger IBS earthquakes require lower local intensities to be recorded. This study demonstrates that a painstaking effort is still needed for unraveling the seismic history of the Dead Sea basin. The results also indicate that such a study will likely be highly rewarding. Copyright 2011 by the American Geophysical Union.

Rust J.,Steinmann Institute for Geology | Bergmann A.,Steinmann Institute for Geology | Bartels C.,Dortmunder Allee 79 | Schoenemann B.,Institute For Biologie Und Didaktik | And 2 more authors.
Arthropod Structure and Development | Year: 2016

The approximately 400-million-year old Hunsrück biota provides a unique window into Devonian marine life. Fossil evidence suggests that this biota was dominated by echinoderms and various classes of arthropods, including Trilobita, stem lineage representatives of Euarthropoda, Chelicerata and Eucrustacea, as well as several crown group Chelicerata and Eucrustacea. The Hunsrück biota's exceptional preservation allows detailed reconstructions and description of key-aspects of its fauna's functional morphologies thereby revealing modes of locomotion, sensory perception, and feeding strategies. Morphological and stratigraphic data are used for a critical interpretation of the likely habitats, mode of life and nutritional characteristics of this diverse fauna. Potential predators include pycnogonids and other chelicerates, as well as the now extinct stem arthropods Schinderhannes bartelsi, Cambronatus brasseli and Wingertshellicus backesi. Mainly the deposit feeding Trilobita, Marrellomorpha and Megacheira, such as Bundenbachiellus giganteus, represents scavengers. Possibly, opportunistic scavenging was also performed by the afore-mentioned predators. Most of the studied arthropods appear to have been adapted to living in relatively well-illuminated conditions within the photic zone. Fossil evidence for associations amongst arthropods and other classes of metazoans is reported. These associations provide evidence of likely community structures. © 2016 Elsevier Ltd.

Kuhl G.,Steinmann Institute for Geology | Poschmann M.,Generaldirektion Kulturelles Erbe RLP | Rust J.,Steinmann Institute for Geology
Geological Magazine | Year: 2013

A new sea spider (Arthropoda: Pycnogonida) from the Lower Devonian Hunsrück Slate (Germany) is described as Pentapantopus vogteli gen. et sp. nov. This is the fifth pycnogonid species known from this exceptional fossil Lagerstätte. The most conspicuous character of the new species is the presence of five pairs of walking legs. This character, in concert with a reduced abdomen, indicates a phylogenetic position of P. vogteli among the crown group pycnogonids. P. vogteli extends the knowledge of fossil pycnogonid body plans and underlines the significance of the Hunsrück Slate, as this locality shows the highest diversity of sea spiders for the entire fossil record so far. Copyright © Cambridge University Press 2013.

Discover hidden collaborations