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Mikuz V.,University of Ljubljana | Bartol M.,Paleontoloski Institute Ivana Rakovca ZRC SAZU | Soster A.,Visnja vas 9
Geologija | Year: 2014

The article discusses fossil porgy fish teeth found in Middle Miocene (Badenian) sandy marl from Mastni hrib near Škocjan in Dolenjska. The teeth belong to the species Pagrus cinctus (Agassiz, 1836) and represent the first find in the Krka basin. In sediments of the Central Paratethys and the Mediterranean, the fossil remains of porgy fish are relatively common. Source

Mikuz V.,University of Ljubljana | Bartol M.,Paleontoloski Institute Ivana Rakovca ZRC SAZU
Geologija | Year: 2014

The article discusses a vertebra and a small shark tooth found in the Miocene Govce sandstone near Govce west of Laško in central Slovenia. The vertebra belongs to a shark of the superorder Galeomorphii but we could not determine it with greater precision. The small tooth was assigned to Carcharias cf. taurus Rafinesque, 1810. The nannofossils in the sample are scarce and did not allow dating at biozone precision. Source

O'Dogherty L.,University of Cadiz | Carter E.S.,Portland State University | Gorican S.,Paleontoloski Institute Ivana Rakovca ZRC SAZU | Dumitrica P.,Dennigkofenweg 33
Geological Society Special Publication | Year: 2010

This paper summarizes 30 years of research on the biostratigraphy of Triassic radiolarians and presents a correlation of currently-used radiolarian zonations established in North America, Europe, Japan and Far East Russia. An up-to-date stratigraphic distribution of all hitherto described and still valid Triassic genera is provided. This new range chart consists of 282 genera and allows an accurate dating to substage level. It also clearly manifests general trends in radiolarian evolution through the Triassic. The end-Permian extinction, the most severe extinction in the history of radiolarians, was followed by a long recovery until the early Anisian. The middle and late Anisian were then characterized by a rapid explosion of new morphologies. Maximum generic diversity was attained during the early Carnian, but the first severe extinctions also occurred in the Carnian. A progressive decline of diversity took place through the Norian and Rhaetian, and ended in a mass extinction around the Triassic-Jurassic boundary. © The Geological Society of London 2010. Source

Moix P.,Rue de la Combe 55 | Gorican S.,Paleontoloski Institute Ivana Rakovca ZRC SAZU
Geodinamica Acta | Year: 2013

Two large blocks of red bedded chert identified within the Late Cretaceous-Paleocene Bornova mélange in northern Karaburun Peninsula yielded Jurassic (late Bathonian-early Oxfordian) and Cretaceous (middle-late Albian) radiolarian assemblages. These new data confirm the correlation of the Bornova mélange with the Bornova Flysch Zone (BFZ) and the Izmir-Ankara mélanges. A review of all previously obtained ages in chert blocks of the BFZ and the Izmir-Ankara mélanges is provided in order to strengthen this correlation. © 2014 Taylor & Francis. Source

Guex J.,University of Lausanne | O'Dogherty L.,University of Cadiz | Carter E.S.,Portland State University | Gorican S.,Paleontoloski Institute Ivana Rakovca ZRC SAZU | And 2 more authors.
Geobios | Year: 2012

Radiolarians are Cambrian to recent holoplanktonic marine protists with morphologically very diverse siliceous skeletons. In the Mesozoic, two main groups are differentiated: nassellarians (mostly conical, composed of one or more consecutive segments) and spumellarians s.l. (generally spherical, composed of one or more concentrical shells). Following the extensive radiolarian research over the past decades, it is now possible to trace the development of some Mesozoic radiolarians through time and to reliably reconstruct several phyletic lineages. In this study, we analyse some lineages with well-marked trends in skeletal development and compare these trends with those observed in other marine organisms. The most usual geometrical transformations occurring in radiolarians are characterized by an increase of the surface of the shell. In several nassellarians, we observe a progressive inflation of the test, leading to a spherization. In some groups, such a trend leads to cryptocephalization, a phenomenon analogous to the orbulinization of some Tertiary foraminifers. The development of a terminal tube or of apertural arches is also frequent in the nassellarians. In many respects, the transformations observed in the spumellarians are related to the same kind of geometrical modifications. For example, the addition of an arch to a polar spine in Baumgartneria, of a ring in the Saturnalids, of a button or spine also in the ring of Aurisaturnalis, are clear examples of an increase of the shell surface through time. Proterogenesis is also frequent in nassellarians and spumellarians s.l., especially in the Pyloniaceae and Centrocubidae where new structures first develop in the earliest ontogenetic stage. The initial antapical spicule frequently evolves by doubling or quadrupling of the antapical spine, leading to entirely new modes of growth in subsequent descendants and to forms which are cryptogenic with regard to their ancestors. During extinction crises corresponding to highly stressful periods, radiolarians tend to lose the structures which were developed during their preceding evolution: loss of the ring in the Axoprunids, loss of the twisting of the spines in Tipperella, disappearance of inflated nassellarians in the Early Jurassic, etc. Such losses lead to the reappearance of primitive characters. © 2012. Source

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