Lower Devonian ostracods from the Istanbul area, Western Pontides (NW Turkey): Gondwanan and peri-Gondwanan affinities

2014 ◽  
Vol 152 (2) ◽  
pp. 298-315 ◽  
Author(s):  
EWA OLEMPSKA ◽  
ATİKE NAZİK ◽  
ŞENOL ÇAPKINOĞLU ◽  
DİLEK GÜLNUR SAYDAM-DEMİRAY
Keyword(s):  
Lower Devonian ◽  
High Energy ◽  
Species Level ◽  
Low Energy ◽  
Geographical Proximity ◽  
Cantabrian Mountains ◽  
Early Devonian ◽  
Larval Stages ◽  
Nw Turkey ◽  
Late Emsian

AbstractA Lower Devonian silicified ostracod fauna has been recovered from limestone interbeds in the Büyükdere section of the Kozyatağı Member of the Pendik Formation. Forty-one species belonging to 33 genera have been recognized. Twenty-three are already known, and 15 are described in open nomenclature. One genus and three species (Omerliella rectangulatagen. et sp. nov.,Microcheilinella istanbulensissp. nov. andRoundyella goekchenaesp. nov.) are described. Silicified larval stages of trilobites, agglutinated foraminifers and conodonts co-occur with the ostracods. The ostracod assemblages are ‘mixed faunas’, between the epineritic Eifelian Mega-Assemblage, representative of high-energy environments, and the basinal Thuringian Mega-Assemblage, representative of low-energy environments. The conodont faunas of the Pendik Formation represent theserotinus,patulusandpartitusbiozones of the late Emsian – earliest Eifelian. The Emsian ostracods of NW Turkey show numerous species-level links between the Western Pontides (Istanbul Terrane) and assemblages of contemporaneous faunas of the Cantabrian Mountains (Spain), Morocco and Thuringia (Germany), and of similar biofacies. This supports the notion that the Istanbul Terrane, Armorican terrane-collage and northern margins of Gondwana were in geographical proximity in late Early Devonian time.

The dipnoan species, Sorbitorhynchus deleaskitus , from the Lower Devonian of Guangxi, China

1993 ◽  
Vol 340 (1291) ◽  
pp. 1-24 ◽  
Keyword(s):  
Lower Devonian ◽  
Early Devonian ◽  
Hyoid Arch ◽  
New Perspective ◽  
Dermal Bones ◽  
Late Emsian

A dipnoan species from the Emsian of Guangxi, China, Sorbitorhynchus deleaskitus , which has previously been diagnosed in the appendix to a more general paper on dipnoan phylogeny (Cambell & Barwick 1990), is described in detail. The head is large and heavily ossified, with cosmine on the external dermal bones. The dental plates are thick and have few poorly defined large tuberosities towards their anterolateral edges. It is the only Early Devonian dipnoan for which the full hyoid arch, gular, basibranchial, and submandibular plates are preserved, and in which the parasphenoid is clearly defined. In many features the genus is more advanced than Dipnorhynchus , but in none is it more advanced than Dipterus , apart from the loss of the buccohypophysial foramen. It gives a new perspective on late Emsian evolution of the group, and reinforces our concept of an independently developing dentine-plated line contemporaneous with a true tooth-plated line.

scholarly journals Ornamentation of dermal bones of Placodermi from the Lower Devonian of Morocco as a measure of biodiversity

Geologos ◽  
2017 ◽  
Vol 23 (2) ◽  
pp. 65-73
Author(s):  
Mateusz Antczak ◽  
Błażej Berkowski
Keyword(s):  
Lower Devonian ◽  
Interspecific Variation ◽  
Species Level ◽  
The Body ◽  
Early Devonian ◽  
Terrestrial Vertebrates ◽  
Evolutionary Changes ◽  
Early Vertebrates ◽  
Dermal Bones ◽  
Scanning Electron

AbstractDermal bones are formed early during growth and thus constitute an important tool in studies of ontogenetic and evolutionary changes amongst early vertebrates. Ornamentation of dermal bones of terrestrial vertebrates is often used as a taxonomic tool, for instance in Aetosauria, extant lungfishes (Dipnoi) and ray-finned fishes (Actinopterygii), for which it have been proved to be of use in differentiating specimens to species level. However, it has not been utilised to the same extent in placoderms. Several features of the ornamentation of Early Devonian placoderms from Hamar Laghdad (Morocco) were examined using both optical and scanning electron microscopy to determine whether it is possible to distinguish armoured Palaeozoic fishes. Four distinct morphotypes, based on ornamentation of dermal bones, are differentiated. These distinct types of ornamentation may be the result of either different location of dermal plates on the body or of ontogenetic (intraspecific) and/or interspecific variation.

scholarly journals Revisiting the spore assemblages from the Lower Devonian Posongchong Formation of Wenshan, Yunnan Province, southwestern China

2017 ◽  
Vol 108 (4) ◽  
pp. 339-354 ◽  
Author(s):  
B. Cascales-Miñana ◽  
J. Z. Xue ◽  
G. Rial ◽  
P. Gerrienne ◽  
P. Huang ◽  
...  
Keyword(s):  
South China ◽  
Yunnan Province ◽  
Lower Devonian ◽  
Age Determination ◽  
Species Level ◽  
Southwestern China ◽  
Early Devonian ◽  
Index Species ◽  
Continental Deposits ◽  
Spore Diversity

ABSTRACTThe Lower Devonian Posongchong Formation (Wenshan, Yunnan Province, southwestern China) consists of a series of continental deposits with an outstanding plant megafossil diversity. More than 20 years ago, this formation was interpreted as ‘Siegenian' (∼Pragian) in age based on palynology. However, such interpretation needs further evidence because of the known differences between the dispersed spore assemblages from South China and Euramerica/northwestern Gondwana. Here, we present new dispersed spore assemblages recently recovered from the Posongchong Formation. The isolated spore diversity is highly diverse, with 18 genera and 32 species. The recognised taxa include, among others, Ambitisporites avitus, Aneurospora conica, Aneurospora posongchongensis sp. nov., Aneurospora xujiachongensis, Apiculiretusispora plicata, Archaeozonotriletes chulus, Concentricosisporites agradabilis, Dibolisporites echinaceus, Emphanisporites rotatus, Gneudnaspora divellomedia, Latosporites ovalis, Retusotriletes triangulatus, Tetrahedraletes medinensis and Verrucosporites polygonalis, with Aneurospora and Retusotriletes being the most abundant forms. The known Posongchong palynoflora (previous spore data included) suggests that the Posongchong Formation assemblages can be correlated with the Pragian interval of the polygonalis–wetteldorfensis Oppel Zone (PoW). This age determination is supported by the presence of index species of PoW, such as Verrucosporites polygonalis, Dictyotriletes subgranifer and Camarozonotriletes parvus (sensu Steemans, 1989), the latter being known only from the Pragian of Belgium and Germany. Recent advances in the study of the marine faunas in the overlying sequences also indicate a Pragian age for the Posongchong Formation. This new investigation of the Posongchong palynoflora highlights differences of abundance at species level between the Gondwanan–Laurussian floras during the Early Devonian.

scholarly journals Sequences, stratigraphy and scenarios: what can we say about the fossil record of the earliest tetrapods?

2010 ◽  
Vol 278 (1704) ◽  
pp. 432-439 ◽  
Author(s):  
Matt Friedman ◽  
Martin D. Brazeau
Keyword(s):  
Fossil Record ◽  
Large Scale ◽  
Past Research ◽  
Species Level ◽  
Late Devonian ◽  
Early Devonian ◽  
Order Of Magnitude ◽  
Evolutionary Event ◽  
Devonian Age ◽  
Late Emsian

Past research on the emergence of digit-bearing tetrapods has led to the widely accepted premise that this important evolutionary event occurred during the Late Devonian. The discovery of convincing digit-bearing tetrapod trackways of early Middle Devonian age in Poland has upset this orthodoxy, indicating that current scenarios which link the timing of the origin of digited tetrapods to specific events in Earth history are likely to be in error. Inspired by this find, we examine the fossil record of early digit-bearing tetrapods and their closest fish-like relatives from a statistical standpoint. We find that the Polish trackways force a substantial reconsideration of the nature of the early tetrapod record when only body fossils are considered. However, the effect is less drastic (and often not statistically significant) when other reliably dated trackways that were previously considered anachronistic are taken into account. Using two approaches, we find that 95 per cent credible and confidence intervals for the origin of digit-bearing tetrapods extend into the Early Devonian and beyond, spanning late Emsian to mid Ludlow. For biologically realistic diversity models, estimated genus-level preservation rates for Devonian digited tetrapods and their relatives range from 0.025 to 0.073 per lineage-million years, an order of magnitude lower than species-level rates for groups typically considered to have dense records. Available fossils of early digited tetrapods and their immediate relatives are adequate for documenting large-scale patterns of character acquisition associated with the origin of terrestriality, but low preservation rates coupled with clear geographical and stratigraphic sampling biases caution against building scenarios for the origin of digits and terrestrialization tied to the provenance of particular specimens or faunas.

New Early Devonian (late Emsian) placoderms from Belarus

2020 ◽  
Vol 94 (4) ◽  
pp. 773-787
Author(s):  
Dmitry P. Plax ◽  
Michael J. Newman
Keyword(s):  
New Species ◽  
Lower Devonian ◽  
New Genus ◽  
Baltic Region ◽  
Early Devonian ◽  
The Baltic ◽  
Enclosing Rocks ◽  
Stratigraphic Chart ◽  
Late Emsian ◽  
Organic Remains

AbstractFour placoderm fishes are described from the Lepel Beds of the Vitebsk Regional Stage of the Lower Devonian (upper Emsian) of Belarus. Two forms are new (Stipatosteus svidunovitchi new genus, new species and Actinolepis zaikai new species) and the other two taxa are left in open nomenclature (Coccosteidae gen. indet. sp. indet.; Placodermi indet. 1). Specimens of all four forms consist of disarticulated, mostly well-preserved plates (some are worn at the edges) originating from the cores of six boreholes. Additionally, the paper presents data on organic remains with the placoderms. A detailed lithological description of the enclosing rocks and a taphonomic description of the ichthyofauna are also provided. The 2010 Stratigraphic Chart of the Devonian deposits of Belarus was used as the stratigraphic basis. The presence of the genus Actinolepis Agassiz, 1844 in these deposits as well as in the Emsian of the Baltic region and Spitsbergen suggests a regional paleogeographic connection at this time.UUID: http://zoobank.org/368b44df-e9e9-417c-a0e0-f7e138b7f4ec

Low energy vs. high energy depositional settings and related sedimentary bodies in early Senenian rudist bearing carbonate shelves (central-southern Italy)

2001 ◽  
Vol 28 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Gabriele Carannante ◽  
A. Laviano ◽  
D. Ruberti ◽  
Lucia Simone ◽  
G. Sirna ◽  
...  
Keyword(s):  
Southern Italy ◽  
High Energy ◽  
Low Energy ◽  
Depositional Settings

Transportation: Fuel Energies

2017 ◽  
Author(s):  
Peter Rez
Keyword(s):  
Energy Density ◽  
Fossil Fuels ◽  
High Energy ◽  
Ease Of Use ◽  
Low Energy ◽  
High Energy Density ◽  
Nuclear Fuels ◽  
Liquid Hydrocarbons ◽  
Transportation Fuel ◽  
Journey Time

Transportation efficiency can be measured in terms of the energy needed to move a person or a tonne of freight over a given distance. For passengers, journey time is important, so an equally useful measure is the product of the energy used and the time taken for the journey. Transportation requires storage of energy. Rechargeable systems such as batteries have very low energy densities as compared to fossil fuels. The highest energy densities come from nuclear fuels, although, because of shielding requirements, these are not practical for most forms of transportation. Liquid hydrocarbons represent a nice compromise between high energy density and ease of use.

scholarly journals Low-Energy Electron Damage to Condensed-Phase DNA and Its Constituents

2021 ◽  
Vol 22 (15) ◽  
pp. 7879
Author(s):  
Yingxia Gao ◽  
Yi Zheng ◽  
Léon Sanche
Keyword(s):  
Condensed Phase ◽  
Genetic Material ◽  
High Energy ◽  
Dna Lesions ◽  
Low Energy ◽  
Experimental Investigations ◽  
Experimental Conditions ◽  
Strand Breaks ◽  
Sequence Of Events ◽  
Wide Range

The complex physical and chemical reactions between the large number of low-energy (0–30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as crosslinks, single strand breaks, base modifications, and cleavage, as well as double strand breaks and other cluster damages. When crosslinks and cluster damages cannot be repaired by the cell, they can cause genetic loss of information, mutations, apoptosis, and promote genomic instability. Through the efforts of many research groups in the past two decades, the study of the interaction between LEEs and DNA under different experimental conditions has unveiled some of the main mechanisms responsible for these damages. In the present review, we focus on experimental investigations in the condensed phase that range from fundamental DNA constituents to oligonucleotides, synthetic duplex DNA, and bacterial (i.e., plasmid) DNA. These targets were irradiated either with LEEs from a monoenergetic-electron or photoelectron source, as sub-monolayer, monolayer, or multilayer films and within clusters or water solutions. Each type of experiment is briefly described, and the observed DNA damages are reported, along with the proposed mechanisms. Defining the role of LEEs within the sequence of events leading to radiobiological lesions contributes to our understanding of the action of radiation on living organisms, over a wide range of initial radiation energies. Applications of the interaction of LEEs with DNA to radiotherapy are briefly summarized.

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