Results 1 to 10 of about 92,675 (274)

Terrestrialization in the Ordovician

open access: yesGeological Society, London, Special Publications, 2022
Abstract This contribution reviews the evidence for terrestrial organisms during the Ordovician (microbial, land plant, fungal, animal) and for the nature of the terrestrial biota. The evidence regarding the origin and early diversification of land plants combines information from both fossils and living organisms.
Wellman, Charles   +2 more
openaire   +3 more sources

Sheltered preservation in Ordovician trilobites [PDF]

open access: yesFossil Record, 2021
Abstract. Articulated holaspid specimens of Placoparia Hawle and Corda, 1847 and Eoharpes Raymond, 1905 entombed inside cephalopod conchs and under the remains of large illaenid, asaphid, cyclopygid and dalmanitid trilobites from the Middle Ordovician Šárka Formation of the Prague Basin (Czech Republic) are described and discussed.
Fatka,Oldřich, Budil,Petr, Kraft,Petr
openaire   +6 more sources

Systematics, morphology, and appendages of an Early Ordovician pilekiine trilobite Anacheirurus from Fezouata Shale and the early diversification of Cheiruridae [PDF]

open access: yesActa Palaeontologica Polonica, 2021
Pilekiines are the earliest diverging members of the successful trilobite family Cheiruridae. The pilekiine genus Anacheirurus is characterized by sub-quadratic to sub-oval glabella, pitted genae, and a distinct trunk with elongated pleural spines in ...
FRANCESC PÉREZ-PERIS   +3 more
doaj   +1 more source

The earliest cornulitid on the internal surface of the illaenid pygidium from the Middle Ordovician of Estonia [PDF]

open access: yesEstonian Journal of Earth Sciences, 2017
The earliest cornulitid Cornulites sp. appears in the Darriwilian (Lasnamägi Regional Stage) of Estonia. Internal annulation is present in all Middle Ordovician cornulitids and could be a plesiomorphic character for the group.
Olev Vinn, Ursula Toom, Mare Isakar
doaj   +1 more source

Stratigraphy and facies differences of the Middle Darriwilian Isotopic Carbon Excursion (MDICE) in Baltoscandia [PDF]

open access: yesEstonian Journal of Earth Sciences, 2020
The Middle Darriwilian Isotopic Carbon Excursion (MDICE) is a global isotopic event described in sections from different palaeocontinents. Here we present new stable carbon isotopic data from carbonates of ten sections in different parts of the ...
Leho Ainsaar   +5 more
doaj   +1 more source

Metal enrichment in lithologically complex black shales: a case study from the Tremadocian of NE Estonia [PDF]

open access: yesEstonian Journal of Earth Sciences, 2021
Significantly elevated U, Mo, Zn and Pb contents characterize the Early Ordovician black shales in the Sillamäe area, NE Estonia. The presence of silty interlayers with sulphidic mineralization and authigenic carbonates suggests unique physicochemical ...
Rutt Hints   +4 more
doaj   +1 more source

Upper Ordovician hardgrounds – from localized surfaces to global biogeochemical events [PDF]

open access: yesEstonian Journal of Earth Sciences, 2023
Upper Ordovician hardgrounds display a spectrum of complexity reflecting a range of local to global-scale processes. Hardgrounds are cemented seafloor surfaces typically marked by the presence of encrusting taxa and borings.
Timothy R. Paton   +4 more
doaj   +1 more source

Echinoderm Lagerstätten from high-latitude Gondwana – filling the gap in the Ordovician diversification of the phylum [PDF]

open access: yesEstonian Journal of Earth Sciences, 2023
The phylum Echinodermata is a major component of marine ecosystems since the first appearance of echinoderms in the Cambrian. Like other metazoan phyla, echinoderms underwent two major evolutionary pulses in early Palaeozoic times: the Cambrian Explosion
Martina Nohejlová   +4 more
doaj   +1 more source

A Cambrian–Ordovician Terrestrialization of Arachnids [PDF]

open access: yesFrontiers in Genetics, 2020
Understanding the temporal context of terrestrialization in chelicerates depends on whether terrestrial groups, the traditional Arachnida, have a single origin and whether or not horseshoe crabs are primitively or secondarily marine. Molecular dating on a phylogenomic tree that recovers arachnid monophyly, constrained by 27 rigorously vetted fossil ...
Jesus Lozano-Fernandez   +8 more
openaire   +7 more sources

Changes in shelf phosphorus burial during the Hirnantian glaciation and its implications [PDF]

open access: yesEstonian Journal of Earth Sciences, 2023
The Late Ordovician mass extinction occurred during an icehouse interval, accompanied by the glaciation of the supercontinent Gondwana, which was located at the South Pole at that time.
Johann Müller   +4 more
doaj   +1 more source

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