The first recovery of the conodont Hindeodus parvus from Žiri (Slovenia) a few years ago highlights this area for Early Triassic biostratigraphical study. Systematic sampling of five sections in the ...Idrija–Žiri area has yielded the new species Platyvillosus corniger sp. nov. and Neospathodus planus sp. nov. Based on these new species and other conodont elements collected here, nine discrete conodont Unitary Association (UA) zones are proposed for this area. In ascending order they are: Eurygnathodus costatus Zone (UA 1), Eurygnathodus hamadai Zone (UA 2), Foliella gardenae Zone (UA 3), Neospathodus robustus Zone (UA 4), Platyvillosus corniger Zone (UA 5), Platyvillosus regularis Zone (UA 6), Triassospathodus hungaricus Zone (UA 7), Triassospathodus symmetricus Zone (UA 8), and Neospathodus robustispinus Zone (UA 9). The conodont and δ13C data indicate that these conodonts span the Dienerian/Smithian (i.e. Induan/Olenekian) boundary interval to the Spathian, and they also indicate that Triassospathodus hungaricus Zone (UA 7) does not occur at the base of the Spathian. These conodont zones are valuable for stratigraphic correlation within Central and southern Europe, and they also promote a better correlation worldwide. Conodonts in the Idrija–Žiri area were adapted to a shallow-water environment in an epeiric ramp.
•Nine discrete conodont zones are identified for the Early Triassic in Idrija–Žiri, Slovenia.•δ13C data and conodonts indicate that these sections span the late Dienerian to Spathian.•According to δ13C data the Smithian/Spathian boundary is characterized by Foliella gardenae.•These conodonts were adapted to a shallow-water environment in an epeiric ramp.•This unique conodont sequence was probably the result of paleoecological influence and/or provincialism.
This study presents the results of the conodont biostratigraphy and microfacies analysis carried out on the pelagic limestones of the Upper Triassic Dovško Section in Slovenia, which represents the ...eastern part of the Slovenian Basin. The age of the section ranges from the Lacian 1 to the Alaunian 1. The Lacian part of the succession is predominantly characterized by the representatives of the genus
Ancyrogondolella
. Transitional morphologies towards Alaunian faunas first appear in the Lacian 3 and become common during the Lacian-Alaunian transition. This evolutionary development coincides with a shift in microfacies from a dominantly radiolarian-bearing mudstone-wackestone-packstone to a filament- dominated wackestone-packstone, and the formation of small neptunian dykes, which may reflect environmental perturbations and/or a change in basin geometry. The proliferation of the genera
Epigondolella
and
Mockina
is observed in the Alaunian part of the section, though the genus
Ancyrogondolella
is still present in this interval. Systematic description of the conodont taxa is provided, and seven new species and two new subspecies are established. The new advances will be of great value in further biostratigraphic studies, especially in areas without ammonoid faunas, and in the reconstruction of the paleogeography of the Slovenian Basin.
During the earliest Triassic microbial mats flourished in the photic zones of marginal seas, generating widespread microbialites. It has been suggested that anoxic conditions in shallow marine ...environments, linked to the end‐Permian mass extinction, limited mat‐inhibiting metazoans allowing for this microbialite expansion. The presence of a diverse suite of proxies indicating oxygenated shallow sea‐water conditions (metazoan fossils, biomarkers and redox proxies) from microbialite successions have, however, challenged the inference of anoxic conditions. Here, the distribution and faunal composition of Griesbachian microbialites from China, Iran, Turkey, Armenia, Slovenia and Hungary are investigated to determine the factors that allowed microbialite‐forming microbial mats to flourish following the end‐Permian crisis. The results presented here show that Neotethyan microbial buildups record a unique faunal association due to the presence of keratose sponges, while the Palaeotethyan buildups have a higher proportion of molluscs and the foraminifera Earlandia. The distribution of the faunal components within the microbial fabrics suggests that, except for the keratose sponges and some microconchids, most of the metazoans were transported into the microbial framework via wave currents. The presence of both microbialites and metazoan associations were limited to oxygenated settings, suggesting that a factor other than anoxia resulted in a relaxation of ecological constraints following the mass extinction event. It is inferred that the end‐Permian mass extinction event decreased the diversity and abundance of metazoans to the point of significantly reducing competition, allowing photosynthesis‐based microbial mats to flourish in shallow water settings and resulting in the formation of widespread microbialites.
After the end‐Permian mass extinction, microbialites filled the ecological niche previously occupied by metazoan reefs. The factors that allowed microbialite‐forming microbial mats to flourish are, however, hotly debated. By investigating the faunal composition and depositional setting of Permian/Triassic boundary microbialites, we propose that the impact of the extinction event on the abundance of metazoans suppressed the biological controls that were previously excluding microbialite development from subtidal environments.
The Teočak section in Bosnia and Herzegovina (Sava-Vardar Zone) composed of the Upper Permian Bellerophon Formation and the Lower Triassic “Werfen Formation” was studied sedimentologically and ...micropaleontologically by using foraminifers and conodonts. The Bellerophon Formation was deposited in a shallow subtidal lagoon rich in biota characterized by typical Changsingian foraminiferal species. Deposition on a shallow epicontinental ramp with pronounced long-term transgression is proposed for the Lower Triassic strata. The recovered conodont faunas are assigned to the Late Permian praeparvus (Changhsingian) and to the Early Triassic isarcica-staeschei (Griesbachian), costatus (? latest Dienerian-early Smithian) and hungaricus (early Spathian) Zones. The studied strata include the Permian-Triassic Boundary as well as the Induan-Olenekian Boundary. The introduced conodont biozonation in the Teočak section is for the first time proposed for the region and is an important contribution for paleobiogeographic correlation of Western Tethys.
•Uppermost Permian and Lower Triassic strata of the Teočak section were studied.•The section is composed of the Bellerophon Formation and the “Werfen Formation”.•The recovered conodont faunas enabled identification of four conodont zones.•Foraminifers of the Bellerophon Formation are marked by typical Changhsingian taxa.•A deposition on a shallow epicontinental ramp is proposed for the Triassic strata.
The Ladinian Pseudozilian formation in the central part of the Sava Folds, Slovenia, was deposited in a deeper marine basin situated among the carbonate platforms lining the western margin of the ...Neotethys. The formation consists of shale and sandstone, hemipelagic limestone, volcanics, and volcanoclastics. At Dole pri Litiji, tuffaceous sandstone contains metre-scale olistoliths dominated by microbialites, solenoporacean algae, sponges, microproblematica and, to a minor extent, corals. Six types of fossil reef associations were recognized based on different proportions of these components. The presence of
Ladinella porata
Ott, dasycladaceans, and solenoporacean algae suggests the olistoliths originate from within the photic zone, perhaps the platform margin or the upper slope. Similar or even identical associations can be found in other Anisian to early Carnian reefs, suggesting the perseverance of reef associations that established themselves during the Middle Triassic recovery. Rather than replacing the older associations, new associations were added through time. The Anisian–early Carnian reef associations thus probably remained present even after the Late Triassic rise of scleractinian corals to dominance.
Upper Permian and lowermost Triassic strata of the Masore section in western Slovenia have been restudied by means of bio- and lithostratigraphy. This section is mainly characterized by a carbonate ...succession of the Bellerophon Formation deposited in a shallow marine ramp environment that was located in the western part of the Paleotethys. The Permian-Triassic boundary (PTB) transition is marked by laminated microbialites – stromatolites interpreted to reflect a deeper ramp environment. The conodont elements recovered enabled the recognition of the Hindeodus praeparvus Zone of the uppermost Permian (Upper Changhsingian) in the Bellerophon Formation. Gondolellids are documented in the PTB transitional interval with microbial microfacies, whereas the Isarcicella isarcica Zone (Lower Griesbachian, Lower Triassic) is recognized in the tectonically separated Werfen Formation just above the microbial microfacies part of the section. The lowermost part of the microbialites is characterized by Late Permian species of foraminifers indicating that at least this part of the section is still Upper Permian.
•The Masore section in Slovenia has been restudied.•The PTB transition is marked by laminated microbialites – stromatolites.•Three conodont faunas are recognized based on Clarkina, Hindeodus and Isarcicella.•Abundant and diverse Changhsingian foraminifers are documented.•The Masore area was located in the western Paleotethyan carbonate ramp-like edge.
Abstract
Crayfishes are rather rare in the fossil record, limiting our understanding of their evolutionary history. We describe and discuss a fossil crayfish from the Miocene of Slovenia. This ...fossil, comprising only the cephalothorax, first pereiopod, and another cheliped, seems closely allied to AustropotamobiusSkorikov, 1907, but also bears an epistome and postorbital carina reminiscent of AstacusFabricius, 1775. For these reasons, it is tentatively assigned to Austropotamobius. It differs from all other Austropotamobius species by the shapes of its epistome cephalic lobe, and postorbital carina, and resemble Austropotamobius torrentium (von Paula Schrank, 1803) most due to its ornamentation. It is therefore described as a new species, Austropotamobius plenicarisp. nov. The new species is associated with brackish water ostracods, most likely reworked from slightly older sediments, suggesting a late Miocene (Messinian) age. The origin of this species and its age show it lived long after the split between Astacus and Austropotamobius, and also probably after the split between the two Austropotamobius species (Au. pallipes and Au. torrentium), and may have been contemporary to, and lived in the area of the diversification of Au. torrentium haplotypes.
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