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This paper discusses the geology of the unique Mansurovo tetrapod and trace fossil locality in the Orenburg Region of Russia (Gostevskaya Formation, Lower Olenekian Substage, Ustmylian Horizon). Sections of 16 trenches are described bed-by-bed and correlated throughout. Based on fossils (Wetlugasaurus malachovi grouping of the Wetlugasaurus Fauna) and lithology, the Mansurovo section correlates with the middle part of the stratotype section of the Gostevskaya Formation (Buzuluk Depression of the East European Platform). The site geology suggests that the four recognized geological members of the section were formed in a varying channel-floodplain environment during alternating depositional cycles. The depositional settings were reconstructed based on rock structure and texture and microlithological examination of thin sections. The tetrapod faunal assemblages, macrofloral remains and unique trace fossil assemblages are also studied. Based on the lithology and facies analysis, the depositional environment is reconstructed for the locality, showing the irregular riverine depositional pattern due to the wandering of river channels and their periodic drying out in a hot and semi-arid climate during the Early Olenekian. Taphonomy of fossil occurrences suggests that the burial took place in a riverine depositional environment affected by strong currents, and that the Temnospondyli probably died in subaquatic conditions. [ABSTRACT FROM AUTHOR]

We record the first occurrence of a microcoprolite assemblage from the Upper Triassic Tiki Formation, Son – Mahanadi Basin, India. The microcoprolite assemblage has been assigned to four new ichnotaxa namely Cylindrocopros gondwanensis igen. et isp. nov., Elliptocopros rewaensis igen. et isp. nov., Convolucopros shadolensis igen. et isp. nov., and Cylindribulbocopros triassicus igen. et isp. nov. based on their external morphology, internal texture, and geochemical composition. Geochemical techniques confirm the phosphatic nature of the microcoprolites recorded from the Tiki Formation. Taken together, the associated fauna and the morphological comparisons between previously known coprolites from the Mesozoic-Cenozoic sedimentary sequences suggest that the Tiki microcoprolites were likely produced by carnivorous actinopterygians. The dentalites or biting traces observed on the external surface of the ichnotaxa recorded herein are the oldest records from the subcontinent. SEM analysis reveals the dominant presence of egg-like mineral spheres ‘microspherulites’, needle- and rod-shaped apatite crystals; however, the microcoprolites are devoid of biotic (floral and faunal) inclusions. Considering the abiotic crystals and geochemistry, we infer that the original faecal matter most likely underwent rapid precipitation during the early phase of mineralisation and had a very high potential for fossilisation. [ABSTRACT FROM AUTHOR]

This article outlines the results of the first-ever ichnological study of the Middle Devonian clastic succession in the South Tatar Arch. The analysis of the stratigraphic distribution of trace fossils in the boreholes revealed several levels with biogenic structures such as ichnofossils and bioturbation, which proved useful for the correlation of the boreholes. The boundary interval of the Pashyian and Timanian Horizons is made up by a succession of three layers: bioturbated siltstones with Spirophyton burrows, limestones, and mudstones with Lingulichnus burrows. The interval can be traced over the entire area of the South Tatar Arch and may serve as an additional marker for the boundary between the horizons.

This study focuses on the paleontological content of the middle Eocene (Bartonian) carbonate–siliciclastic sediments of the Capo Mortola Calcarenite Formation from Olivetta San Michele (Liguria, Italy). Along the succession, there are significant paleoecological changes triggered by the variation in neritic input as a consequence of tectonic and climatic instability. Among microfossils, nummulitids prevail, followed by orthophragmines, smaller benthic, and planktonic foraminifera, whereas mollusks and ichnofossils are the most abundant macrofossils. The sudden changes in the benthic communities due to the progressive increase in fluvial input are recorded throughout the sedimentary succession. An increase in water turbidity caused stressful conditions for autotrophic taxa, reducing their size and abundance. In contrast, filter feeders became dominant, suggesting an increase in dissolved and suspended nutrients. Ichnological analysis shows environmental fluctuations controlled by the transport of neritic material offshore, thus confirming the general deepening trend of the studied succession. In the upper part of the succession, we recorded an alternation between gravity flows and marly sediments that are interpreted as short-term alternations between low and intense precipitations. The gravity flows yield taxa such as larger benthic foraminifera (LBF), smaller benthic and planktonic foraminifera, mollusks, and corals. In turn, marls display only a few LBF and abundant smaller benthic and planktonic foraminifera. In these intervals, the increase in planktonic foraminifera also suggests a deepening of the carbonate ramp coinciding with a reduction of light that did not favor the development of LBF. These changes are probably related to the climatic dynamics that occurred in the Bartonian in the western Tethys. [ABSTRACT FROM AUTHOR]

Three ichnospecies of Lophoctenium (L. comosum , L. richteri and L. cf. haudimmineri) are reported from the Upper Devonian Argiles de Marhouma Formation (southwestern Algeria) for the first time. This formation contains a diverse assemblage of trace fossils belonging to the Nereites ichnofacies. We describe three ichnospecies of Lophoctenium that correspond to three different feeding strategies among the diverse ichnofauna of the Argiles de Marhouma Formation. The strategy of L. comosum evidences food-rich sediments as it maximises the amount of collected food per foraged distance. The strategy of L. richteri is probably most efficient for feeding in slightly less nutrient rich sediment, but gives the opportunity to discover more prolific feeding sites by moving on longer distances. The strategy with a straight central burrow and probes on both sides of the main burrow with long interspaces (L. cf. haudimmineri) was presumably used in the least food rich sediment. It seems that the Lophoctenium was widespread in the Devonian, but restricted to seas surrounding Gondwana. [ABSTRACT FROM AUTHOR]

Bioerosion structures, including holes, pits, and grooves, on the surface of benthic foraminiferal tests from the Upper Cretaceous and Paleogene of Western Siberia are studied. Their morphology is examined, their possible origin and the paleogeographic and stratigraphic distribution in sections representing marine basins of Western Siberia are discussed. The ichnospecies assemblage studied includes Oichnus simplex Bromley, 1981, O. paraboloides Bromley, 1981, O. gradatus Nielsen et Nielsen, 2001, and O. ovalis Bromley, 1993. [ABSTRACT FROM AUTHOR]

The Tertiary-age deep-marine succession cropping out between Tarifa and Algeciras can be subdivided into two units, namely the Late Eocene-?Early Oligocene Getares Unit and the overlying Oligocene-?Early Miocene Algeciras Formation. These strata comprise six sedimentary facies, ranging from thick-bedded sandstones to mudstones. The depositional settings are variable, comprising sandstone/calcarenite packages with intercalated mudstones and marls. The lowermost coarse-grained package is the Getares Unit (fan-fringe setting). This is overlain by the thick-bedded sandstones of the Algeciras Fm (channel, channel-margin setting) which pass upwards into more laterally-extensive beds (sheet-like lobe). Sediments were derived from a coastal setting to the north, as evidenced by occasionally abundant plant remains, from direct fluvial input (hyperpycnal flow). Within this succession, 34 ichnogenera (48 ichnospecies) have been recorded, including, Belorhaphe, Capodistria, Chondrites, Circulichnis, Cochlichnus, Cosmorhaphe, Desmograpton, Gordia, Halopoa, ?Helicorhaphe, Helminthopsis, Helminthorhaphe, Imponoglyphus, Lorenzinia, Megagrapton, Oldhamia, Ophiomorpha, Palaeophycus, Paleodictyon, ?Phycodes, Phycosiphon, Planolites, Protopaleodictyon, Protovirgularia, Scolicia, Skolithos, Spirophycus, Spirophyton, Spirohaphe, Taenidium, Teichichnus, Thalassinoides Urohelminthoida and Zoophycos. Of the ichnofossil assemblages that were defined, most are concentrated in the fan-fringe (Getares Unit; 74%) and channel/channel-margin (lowermost Algeciras Fm; 41%) settings, with a marked reduction in the sheet lobe system (uppermost Algeciras Fm; 9%). The ichnofaunal assemblage from the Tarifa-Almeria section represents the Nereites ichnofacies, or more specifically, the Paleodictyon and Nereites subichnofacies, both typified by abundant graphoglyptids. Deposition in the Algeciras-Tarifa region commenced with the mudstones underlying the Getares Unit followed by a sandstone package (fan fringe; Punta de Getares), indicative of fan progradation. Subsequent mudstones suggest a phase of quiescence before the deposition of the thick, sandy hyperpycnites in the lower part of the Algeciras Fm (Punta del Carnero I & II) where deposition was probably related to flooding events in the source rivers to the N. These were subsequently overlain by the Tarifa area lobe sediments. Deposition of the succession coincided with the transition from a Greenhouse to an Icehouse climatic regime (Eocene-Oligocene) and this change may be reflected in the marked reduction in ichnofaunas moving from the lower (Punta del Carnero) to the upper (Tarifa) Algeciras Fm. [ABSTRACT FROM AUTHOR]

Freshwater crayfishes are among the most successful freshwater animals and are quite important for society economically, ecologically, and culturally. Since crayfishes are almost exclusively restricted to freshwater, their dispersion potential is much lower than that of marine crustaceans. Their biogeographic distribution is thus the result of a still poorly known long and complex evolutionary history. Most of the efforts made to untangle this history have worked from the distribution of extant crayfishes and their phylogenetic relationships, seldom using the fossil record. We here review the state of our current published knowledge on the fossil record of crayfishes, from their fossilized bodies and burrows. We review the Late Triassic Enoploclytia porteri Miller & Ash, 1988 , one of the oldest crayfish body fossils, and show it is most likely a freshwater crayfish and assigned mistakenly to a marine genus. We also discuss burrows from Argentina, suggesting they are actually insect burrows, and burrows and an isolated claw from Libya, which we herein interpret as most likely from brachyuran crabs. We list a total of 65 occurrences or groups of occurrences from across the world and from the Late Devonian to Pleistocene fossils. This long history strengthens the current hypothesis that crayfishes inhabited Pangea and diversified partly via vicariance due to Pangea's breakup during the Mesozoic and into the Cenozoic. Our review also highlights the importance of fossil burrows and body fossils to understand modern faunas and the importance of taxonomic revision of fossil taxa. [ABSTRACT FROM AUTHOR]

The western Iberian Chain of NE Spain represents a lateral prolongation of the West Asturian-Leonese Zone. As other proximal sectors fringing NW Gondwana, the chain comprises a con­formable and continuous FurongianâTremadocian transition, comprising a thick (3600â4500 m) Lower Ordovician sedimentary succession, exclusively composed of siliciclastic strata and deposited in mid-latitude (temperate) waters. Although the shelly fossil record is not abundant, some key trilobites and brachiopods allow the identification of distinct biogeographic links with the Argentinian margin of West Gondwana, Oaxaca (Mexico), and the neighbouring Montagne Noire (France), with which a common biostratigraphic biozonation can be enviaged. Two phosphoritic interbeds rich in linguliformean brachiopods punctuate the Valconchán and Borrachón formations, and represent event beds related to condensation processes and sedimentation of explosive ignimbritic tuffs, respectively.

Over recent decades, the type area of the Maastrichtian Stage in southern Limburg (the Netherlands) and contiguous Belgian territory, and the former ENCI-HeidelbergCement Group quarry (Sint-Pietersberg, Maastricht) in particular, has yielded an exquisitely preserved ichnocoenosis of bioerosional trace fossils, mainly preserved as natural casts in scleractinian corals. More than 20 ichnospecies are here documented, the majority from the type Maastrichtian for the first time. These ichnotaxa constitute a good record of successive colonisation sequences; the present bioerosional ichnocoenosis is regarded to belong to the Entobia ichnofacies.

Trace fossils and palaeopascichnids have been studied in the Basa Formation of the Vendian Asha Group of the South Urals (southwestern periphery of the Suleiman Anticline, Shubino quarry in Ust'-Katav, Chelyabinsk Region of Russia). The general morphology and preservation of ichnofossils have been shown to be similar to the Late Vendian–Early Cambrian subhorizontal bilobate burrows of Didymaulichnus. The paleontological remains have been found to be confined to extremely shallow deposition settings and located stratigraphically below the volcanic tuff layer with a zircon U–Pb isotopic age of 578 ± 7 Ma. Until now, the first occurrence of ichnofossils and the associated "Agronomic Revolution" were dated at ~560–550 Ma. According to our study results, mobile benthos and biological mixing of sediments could have occurred 20–30 Ma earlier. The hypothesis that the onset of the "First Agronomic Revolution" and the "Cambrian Explosion" were far from being close in time was confirmed. [ABSTRACT FROM AUTHOR]

Trace fossils are described from the Lower Triassic Gostevskaya Formation of the Mansurovo locality, Orenburg Region. They are represented by counter impressions at the lower contact of the sandstone with wave ripples. The ichnological characteristics of the trackways and their individual imprints are similar to the ichnospecies Diplichnites triassicus (Linck, 1943), which is widespread in fluvial and lake sediments of the Carboniferous–Triassic of Europe and North America. The most probable trace maker for D. triassicus is a representative of the group of branchiopod arthropods Notostraca, which moved in an aquatic environment. Most likely, a microbial mat developed on the surface of the sand substrate acted as a trace carrier and the arthropod trackways were subsequently preserved and buried with the direct involvement of the microbial mat. [ABSTRACT FROM AUTHOR]

Some circular fossils showing radial structures concentrated in a small area have been recorded from the Criadero Quartzite, 1 km north from El Centenillo village (Iberian Central Zone, SE Spain). The fossils resembling cnidarians have been studied in detail, both at the field and in the laboratory. The specimens have been preserved in thick-grained quartz sandstones. They were analysed in thin sections and rock samples using optical microscopy, micro-reflectance spectroscopy, Fourier transform infrared–attenuated total reflectance spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy and epifluorescence microscopy. The radial structure is composed of ridges and grooves, which correspond to clear and dark ochre bands filled with middle-sized, angular-elongated quartz grains without tractive structures. Mineralogical analyses reveal that composition is based on quartz and illite in both areas. The morphological and compositional features of the fossils have been compared with a set of ichnofossils of multiple taxonomic origins and ages without conclusive results. The preservation is probably produced by the existence of microbial mats on the sand floor and the impression of moulds by authigenic cementation by an unidentified organism. To elucidate the nature of the producer, potentially soft-bodied cnidarian, including fossil medusae and sea anemone, further investigations are needed. [ABSTRACT FROM AUTHOR]

The western Iberian Chain of NE Spain represents a lateral prolongation of the West Asturian-Leonese Zone. As other proximal sectors fringing NW Gondwana, the chain comprises a con­formable and continuous Furongian‒Tremadocian transition, comprising a thick (3600‒4500 m) Lower Ordovician sedimentary succession, exclusively composed of siliciclastic strata and deposited in mid-latitude (temperate) waters. Although the shelly fossil record is not abundant, some key trilobites and brachiopods allow the identification of distinct biogeographic links with the Argentinian margin of West Gondwana, Oaxaca (Mexico), and the neighbouring Montagne Noire (France), with which a common biostratigraphic biozonation can be enviaged. Two phosphoritic interbeds rich in linguliformean brachiopods punctuate the Valconchán and Borrachón formations, and represent event beds related to condensation processes and sedimentation of explosive ignimbritic tuffs, respectively. [ABSTRACT FROM AUTHOR]

The paper presents the first detailed evidence for the Permian and Early Triassic ichnofossils of the Southern Verkhoyansk Region. The possibility of using ichnofossils for reconstruction of terrigenous sedimentation at high latitudes, including environments related to the events of the great Permian mass extinction, was discussed. The results obtained are based on ichnofacial and ichnotextural analyses of about 600 samples collected in 2019 from the Tiryakh-Kobyuma section. We found that the Permian and Triassic sediments of the studied section contain numerous icnofossils attributed to 11 ichnogenera. Four ichnoassemblages were identified. They were referred to two ichnofacies – Zoophycos and Skolithos. The Zoophycos ichnofacies includes two ichnoassemblages: Helmintopsis – Phycosiphon – Zoophycos and the depleted Helmintopsis – Phycosiphon ichnoassemblages. This ichnofacies is confined to well-sorted substrates formed in calm temperately deep-water shelf environments, below the level of storm waves, with reduced oxygen content. The Skolithos ichnofacies includes two ichnoassemblages: Arenicolites – Skolithos and Diplocraterion – Arenicolites. It is characteristic of coastal environments with active hydrodynamics and large inputs of clastic and organic matter. The ichnofacies alternate across the section, reflecting sedimentological changing during the accumulation. The sediments of the lower part of the Nekuchan Formation, corresponding to the Permian mass extinction event, accumulated in calm conditions of a relatively deep shelf. This interval is characterized by the Zoophycos ichnofacies with a depleted Helmintopsis – Phycosiphon ichnoassemblage. The depletion of ichnoassemblage and absence of benthic fossils in this part of the section may be caused by anoxic conditions at the basin bottom. The reconstruction of the Permian and Early Triassic environments agrees well with the results of previous studies based on sedimentological and biofacies data.

Abstract Trace fossils occur in several strata of the Devonian and Carboniferous of the eastern Anti-Atlas, but they are still poorly documented. Here, we describe a fossil swimming trace from strata overlying the Hangenberg Black Shale (correlation largely based on lithostratigraphy; Postclymenia ammonoid genozone, ca. 370 Ma old). We discuss the systematic position of the tracemaker and its body size. This ichnofossil is important for three main reasons: (1) it is considered here to be the first record of Undichna from the Devonian of Gondwana, as far as we know; (2) it is the oldest record of vertebrate trace fossils from Africa; (3) it provides a unique window into the behaviour of Late Devonian fishes for which body-fossils cannot provide direct evidence. Further, we put this discovery into the macroecological context of the palaeoenvironment following the Late Devonian Hangenberg biodiversity crisis.

Trace fossils recording the activity of organisms are common in the Ordovician terrigenous deposits of Tuva. The richest location of ichnofossils was found in the Chirgaky section in the western part of the region. Ichnofossil taxa such as Dimorphichnus Seilacher and Helmintopsis Heer have already been sporadically recorded in other regions of the world. Along with them, the author found predominant trace fossils which should be attributed to a new species of a new subgenus of the genus Rusophycus Hall. [ABSTRACT FROM AUTHOR]

The trace fossil Asthenopodichnium from the Padma Rao open cast mine and Giral lignite mine of the Akli Formation of the Barmer Basin is reported here for the first time. It is recognized to be of Late Paleocene - Early Eocene age. A huge quantity of all-around preservation fossil footprints Asthenopodichnium ichnospecies almond-molded like construction are found in this area. The feeding and dwelling activity of wood-rotting fungi are thought to be A. lignorum trace markers. A. lignorum fossils are fine-granulated wooden sandstone and saved in wooden sticks as an iron-oxide covering of wood segments and logwood. The presence of A. lignorum in the area (Akli Formation) is thought to be an important palaeoecological coastal marine deposition and it is providing additional paleoenvironmental information. [ABSTRACT FROM AUTHOR]

The belt of dark carbonaceous rocks (shale and metamorphic limestone) near Koberovy (Krkonoše-Jizerské Mts. Crystalline Complex) is historically considered a record of the Silurian marine environment, due to the findings of poorly preserved but abundant fossils. Prantl (1948) considered them to be graptolites and, based on existing knowledge, classified the rocks as Silurian. Chlupáč (e.g. 1989) was of a similar opinion. However, later, the same author (Chlupáč 1993) re-interpreted all the remnants of the fauna found as traces of the activity of organisms, thus extending a possible stratigraphic interpretation to virtually entire Phanerozoic. Two different types of Koberovy fossils (two samples) were donated to me by prof. Chlupáč shortly before his death. These are two plates of graphitic calcareous shale, the metamorphism of which is revealed on foliation planes (parallel to bedding) for example by the presence of metamorphic minerals such as white mica (muscovite) and chlorite. The first of these has almost straight to slightly curved "strings" on the surface - probably the original bedding plane - in the left part (oriented according to Fig. 1A), which are dark under normal light; however, surface minerals have a pronounced luster, therefore under a particular illumination, the "strings" appear as light lines. The width of the lines is almost constant, about 0.6 mm. Another group of lines occurs in the centre of the sample. These show a "loop" pattern which can be compared to the double "e" in cursive writing. The width of these lines is around 0.6 mm again, with random fluctuations to lower values. A similar and final biogenic structure is in the top right of the Figure 1A. These are three semi-arcs, the estimated half of which is missing on the sample, probably representing an original 3-D spiral-like structure. Width of this structure is on average slightly larger than the previous two structures: it reaches about 0.8-1.0 mm. The second finding is preserved similarly: on the photograph (Fig. 1B), reflected light is used to highlight the dark fossil on the gray carbonaceous slate background. This sample contains four crescent-shaped segments, two in the "D" position and the remaining two in the "C" position. The next segment has an irregular oval shape and the last is a dashed line. The size of the structures is about 30 mm. Chlupáč (1993) withdrew from the original opinion that these poorly-preserved fossils are graptolites (Prantl 1948, Chlupáč 1953). Instead, he offered an interpretation that these were trace fossils. However, we cannot agree with this view for following reasons: 1. Ichnofossils, which have a similar contour as the spiral structures of the first finding, belong in particular to the ichnogenera Gordia Emmons, 1844 and Spirodesmos Andree, 1920. These fossils are surface grazing traces preserved in hyporelief or epirelief. Such ichnofossils have a small conservation potential during regional metamorphism, with movements and chemical transformations on the foliation planes. No rich relief-ichnofauna has been found in regional metamorphic rocks worldwide. 2. On the other hand, ichnofossils, which have the character of full reliefs, can be preserved even in high-grade metamorphic rocks (staurolite isograd in Jeseníky Mts., Chlupáč 1987a). However, they do not appear on the foliation planes, but are preserved within the rigid beds (quartzite) and are usually best observed in vertical fractures of the rock. The preservation of Gordia ichnofossil in a sequence of rhythmically alternating layers of black calcareous shales and graphitic crystalline limestones (sometimes dolomitic) is hard to imagine. For instance, even in completely unmetamorphosed rocks, surface ichnofossils and trace fossils of shallow tiers do not tend to persist; the limestone environment is specific and largely restrictive for the preservation of ichnofossils; see Savrda et al. (2012). 3. The finding shown in Fig. 1C does not at all resemble ichnofossils of bedding planes. Arches with adjoining areas up to 10 mm wide can be understood, for example, as unfavourably preserved cones of orthocone nautiloids. Alternatively, this finding is somewhat reminiscent of the vertical cross-section of middle tiers of ichnofossils such as Thalassinoides, Palaeophycus, etc. (tubular burrows or complex tube systems), with the proviso that they are large (estimated diameter of the tunnels is nearly 20 mm). According to all macroscopic evidence, however, we observe the bedding plane. Our interpretation, given that the explanation of structures as ichnofossils is extremely unlikely, is that the first case represents relics of graptolites, namely the genus Spirograptus, Cyrtograptus, and Testograptus. If we accept this interpretation, we have a number of examples of similarly preserved graptolites, for example in the Sedlčany-Krásná Hora Roof Pendant (Chlupáč 1987b). There is even an example in the Krkonoše-Jizera Crystalline Complex (near Poniklá; Horný 1964). The second finding is possibly related to nautiloid shells, given that the septa in the sheath correspond in shape and size to the "crescents" observable in the sample. The over-cautious and, in my opinion, incorrect interpretation of the Koberovy fossils (Chlupáč 1993) brought about a "loosening" of the stratigraphy of the Koberovy block (previously attributed by most authors to the Silurian). We argue that the preservation of hyporeliefs and epireliefs of traces in regional metamorphic rocks is unlikely. We return to the opinion that part of the material found probably belongs to graptolites. We understand the efforts of prof. Chlupáč to avoid uncertain statements. However, "degrading" the possible body fossils to ichnofossils is not the right approach. Both categories are independent and each has its own, not fully compatible informative value (e.g., Crimes - Droser 1994) and their own conservation rules in metamorphic rocks. Some poorly preserved paleontological findings may be far more probably body fossils than ichnofossils, therefore we have to reject the ichnofossil interpretation. [ABSTRACT FROM AUTHOR]

The historical stratotype for the Berriasian Stage (Cretaceous System) at Berrias (Ardèche, France) is here re-assessed. It shows a sedimentary record of early to late Berriasian age, part of the pelagic limestone succession of the western Vocontian Basin. We describe a studied section, circa 30 m in thickness, which yields calpionellids, calcareous dinocysts, calcareous nannofossils, and ammonites. The magnetostratigraphy of the section is revised, and calibrated with the biostratigraphy of these fossil groups. Magnetozones M19n to M15r (including M16n.1r) are identified and matched to the calpionellid zonation, with the Alpina to Oblonga biozones represented. • Re-assessment of the historical stratotype for the Berriasian Stage at Berrias. • Calibration of magnetostratigraphy on lower to upper Berriasian calpionellid zones. • A short reversed interval M16n.1r fixed in the upper Simplex Subzone. [ABSTRACT FROM AUTHOR]

This paper documents the occurrence of Skolithos linearis, Planolites beverleyensis, and Thalassinoides isp. in the Cárdenas Formation (Late Cretaceous), southeastern San Luis Potosí, central Mexico. This is the second record of S. linearis for this lithological unit, while P. beverleyensis and Thalassinoides isp. are documented for the very first time in this formation. The ichnoassemblage is referred to the Cruziana Ichnofacies which, in concert with associated invertebrate body fossils (Exogyra costata), suggest a shoreface setting with moderate- to low-energy conditions and episodic storms. [ABSTRACT FROM AUTHOR]

The presented work summarizes knowledge on the Lunz Beds in the Hronic Považie and Ostrá Malenica nappes of the eastern portion of the Strážovské vrchy Mts. It is based mainly on the results of fild research and geological mapping in the area of the Zliechovská hornatina and Nitrické vrchy Mts. The studied rocks are mainly gray-green or brown sandstones, and locall gray-green siltstones or grey claystones. The sandstones are usually structureless (massive) or laminated, thin- to thick bedded. Contain coalifid plant remains, ichnotaxa Arenicolites isp., Phycodes isp., Planolites isp. and Thalassinoides isp. and siltstone or claystone intraclasts. Petrographically, sandstones represent micaceous subarkose, lithic wacke, less often feldspathic (arkosic) wacke and sublitharenite. The observed vitrinite reflctance values 0.95–0.97 % Ro indicate a relatively high diagenetic transformation of the Lunz Beds, where the maximum temperatures reached 131–150 °C. Such conditions were probably achieved during the tectonic burial of the rocks within the nappe structure and later subsidence due to the deposition of superimposed (post-nappe) sediments of the Cenozoic basins.

On 13 July 2004, during an expedition exploring biodiversity along the northern Mid-Atlantic Ridge, an ROV dive recorded videos of numerous sublinear sets of holes in sediment at ca. 2,082 m depth. The location was north of the Azores. Each set appeared track-like. Lengths of individual series ranged from < 1 m to many meters. Each was straight or gently curved. Some series intersected or crossed. Close examination of the holes showed them to be elongate, with the long axis parallel to the axis of the series. The holes were ca. 6 × 1.5 cm, with distance between holes similar to hole length. The holes that appeared to be most recently formed were each surrounded by raised sediment. Holes that appeared older were partly filled with sediment and the raised surrounding sediment was less obvious. Overall, these lebensspuren created small-scale heterogeneity in the local soft-bottom benthic ecosystem. The source of the holes or how they were constructed is unknown, but the raised sediment may indicate excavation by an infaunal organism or digging and removal by e.g., a feeding appendage of a large epifaunal animal. None of our closeups showed any sign of living organisms inhabiting the holes. Whether the holes were connected beneath the sediment surface was not visible. The traces observed are reminiscent of ichnofossils reported from deep marine facies. We hope that future studies of the lebensspuren we report here will resolve the mystery of what created them.

The Silurian–Devonian strata of the Paraná Basin (southern Brazil) have a wide variety of ichnofossils. The first records date from the beginning of the last century, with pioneering studies in 1912 addressing the Furnas and Ponta Grossa formations. Significant advances in the ichnological knowledge of these units occurred between the 1980s and 1990s, emphasizing ichnotaxonomic characterizations. These ichnological studies were important for better understanding and describing the main depositional environments, ecological strategies, biostratigraphy, and the relation with the preserved paleofauna. In this contribution, we review this knowledge and analyze the distribution and paleoecological significance of Zoophycos, the most remarkable ichnotaxon in the Lower Paleozoic beds of the Paraná Basin.

Well preserved asterozoan ichnofossils (Asteriacites lumbricalis von Schlotheim) are documented from calcareous sandstone lenses within the upper part of the Harford Member of the Middle Jurassic (Aalenian) Birdlip Limestone Formation, in the north Cotswolds, central England. The ichnofossils are interpreted as undertraces, generated by the activity of small ophiuroids in a storm-influenced muddy coastal lagoon or bay margin setting. [ABSTRACT FROM AUTHOR]

The Silurian–Devonian strata of the Paraná Basin (southern Brazil) have a wide variety of ichnofossils. The first records date from the beginning of the last century, with pioneering studies in 1912 addressing the Furnas and Ponta Grossa formations. Significant advances in the ichnological knowledge of these units occurred between the 1980s and 1990s, emphasizing ichnotaxonomic characterizations. These ichnological studies were important for better understanding and describing the main depositional environments, ecological strategies, biostratigraphy, and the relation with the preserved paleofauna. In this contribution, we review this knowledge and analyze the distribution and paleoecological significance of Zoophycos, the most remarkable ichnotaxon in the Lower Paleozoic beds of the Paraná Basin. [ABSTRACT FROM AUTHOR]

The Jiaguan Formation and the underlying Feitianshan Formation (Lower Cretaceous) in Sichuan Province yield multiple saurischian (theropod–sauropod) dominated ichnofaunas. To date, a moderate diversity of six theropod ichnogenera has been reported, but none of these have been identified at the ichnospecies level. Thus, many morphotypes have common "generic" labels such as Grallator, Eubrontes, cf. Eubrontes or even "Eubrontes-Megalosauripus" morphotype. These morphotypes are generally more typical of the Jurassic, whereas other more distinctive theropod tracks (Minisauripus and Velociraptorichnus) are restricted to the Cretaceous. The new ichnospecies Eubrontes nobitai ichnosp nov. is distinguished from Jurassic morphotypes based on a very well-preserved trackway and represents the first-named Eubrontes ichnospecies from the Cretaceous of Asia. [ABSTRACT FROM AUTHOR]

Nineteen ichnotaxa, together with algal and invertebrate remains, and various pseudo-traces and sedimentary structures are described from the Torneträsk Formation exposed near Lake Torneträsk, Lapland, Sweden, representing a marked increase in the diversity of biotic traces recorded from this unit. The "lower siltstone" interval of the Torneträsk Formation contains mostly simple pascichnia, fodinichnia and domichnia burrows and trails of low-energy shoreface to intertidal settings. The assemblage has very few forms characteristic of high-energy, soft-sediment, foreshore or upper shoreface environments (representative of the Skolithos ichnofacies). Uranium-lead (U-Pb) LA-ICPMS analysis of zircon from a thin claystone layer within the "lower siltstone" interval yielded a maximum depositional age of 584 ± 13 Ma, mid-Ediacaran. Most of the zircon is represented by rounded detrital grains that yield dates between 3.3 and 1.0 Ga. Although the age of the basal sandstone-dominated interval of the Torneträsk Formation remains elusive owing to the absence of fossils, the ichnofossil suite from the overlying "lower siltstone" interval lacks deep arthropod trackways, such as Rusophycus and Cruziana, and is suggestive of a very early (Terreneuvian, possibly Fortunian) Cambrian age. The ichnofauna is otherwise similar to early Cambrian trace fossil assemblages from other parts of Baltica, regions further south in modern Europe, and from Greenland. [ABSTRACT FROM AUTHOR]

Cova des Pas de Vallgornera is a unique karst cave located at the Llucmajor coastal platform that stands out not only because of its length, more than 78 km, but also for its particular morphological suite, richness and variety of speleothems and mineral infillings. Although the mineralogy of speleothems and minerals related to hypogene morphologies has been studied and described, the existence of minerals derived from guano deposits was still poorly investigated. The cave hosted bat colonies until the collapse of its natural entrances, circa 2.4 My ago, since then until its discovery in 1968, the cave remained sealed. These particular environmental conditions, kept along millennia, helped the interaction of guano-related leachates with the bedrock and clay deposits provoking dissolution and mineral precipitation. Moreover, thanks to the discovery of guano-associated cave minerals, it has also been possible to determine the presence of morphologies related to ancient guano deposits. In this paper, we report on features caused by bat's biomechanical erosion, bat claws and bat thumb marks and the influence of geobiological modifications caused by guano deposits on stalagmites and fallen boulders, haystack-shaped stalagmites, stalagmites covered in niches and crypto-corrosion features on fallen boulders. In addition, an array of guano-related minerals is reported, being phosphates the most abundant mineral group identified, underlining the broad presence of fluorapatite from all the studied sites. Among the oxides and hydroxides, nordstrandite, gibbsite and todorokite are especially common. Finally, connections between microclimatic conditions in the cave and the location of bat roosting and breeding sites are discussed.

The middle and upper parts of the lower Miocene Santa Cruz Formation (~17–15.9 Ma) in the southeastern Austral-Magallanes Basin (southern Patagonia, Argentina) crop out as a fluvial succession that in parts is pedogenically modified. The study of the paleosols of this unit combined with the study of ichnofossils, microremains, and fossil vertebrates present in these allows us to reconstruct past environmental, ecological, and climatic conditions, as well as paleolandscape evolution of the Santa Cruz Formation during ~1 my. These reconstructions demonstrate three different stages during which very weak to moderate pedogenesis took place. The first one (middle part of the unit) is an epiclastic distal floodplain bearing Calcisols or paleo-calcic Inceptisols, which record a relatively dense vegetation integrating trees, shrubs, palms, and short grasses. Soil fauna is scarce and it is in association with a vertebrate fauna typical of coastal “Santacrucian assemblages”. The second landscape stage (the bottom of the lowermost upper part of the unit) is composed of epiclastic distal floodplain areas and minor pyroclastic proximal floodplain settings that contain mainly Vertisols. Vertisols record an ecosystem dominated by grasses and palms adapted to variable conditions in hydric availability (C4 plants) and by solitary bee larvae, and adult and nymph soil beetles. Finally, up-section, the third stage attests to the existence of an epiclastic and pyroclastic distal and proximal floodplain over which Protosols developed. Past ecosystems supported grass vegetation (C3 plants), oligochaete annelids and a moderately diverse insect soil fauna (interpreted by their trace fossils) composed of solitary bee larvae, soil beetles and their pupae, cicada nymphs, and myriapods. This combined abiotic (paleosols) and biotic (ichnofossils, microremains, and vertebrates) study indicates that several factors controlled the landscape evolution during the early Miocene of southeastern Patagonia. Highly aggrading fluvial conditions, variations in the position in the floodplain and in sedimentation/pedogenesis ratio, the input of pyroclastic materials, the length of landscape stability, changing hydrologic conditions, and fluctuations of wetter and drier phases in a context of relatively warm and humid climate, seem to be the main factors controlling the landscape.

Trace fossils occur in several strata of the Devonian and Carboniferous of the eastern Anti-Atlas, but they are still poorly documented. Here, we describe a fossil swimming trace from strata overlying the Hangenberg Black Shale (correlation largely based on lithostratigraphy; Postclymenia ammonoid genozone, ca. 370 Ma old). We discuss the systematic position of the tracemaker and its body size. This ichnofossil is important for three main reasons: (1) it is considered here to be the first record of Undichna from the Devonian of Gondwana, as far as we know; (2) it is the oldest record of vertebrate trace fossils from Africa; (3) it provides a unique window into the behaviour of Late Devonian fishes for which body-fossils cannot provide direct evidence. Further, we put this discovery into the macroecological context of the palaeoenvironment following the Late Devonian Hangenberg biodiversity crisis. [ABSTRACT FROM AUTHOR]

The ichnology of the Pleistocene sand sequence of Gravina is described. The trace fossils provide evidence for marine coastal environments, ranging from the lower infralittoral to intertidal. The study is based on two sections, at Lama La Noce and at Notargiacomo's Quarry respectively. Meniscate backfill structures produced by echinoids (Schizaster canaliferus) occur in thin clay horizons. Sand subst-rates are dominated by Ophiomorpha, Thalassinoides, Cylindrichnus and vertical equilibrium traces. Two new ichnospecies are erected: Cylindrichnus errans, which has lateral spreite—like displacement of the shaft: and Dactyloidites peniculus for finely branched, radiating spreite structures.

An updated stratigraphic subdivision of the Ediacaran and Terreneuvian in the Alcudia valley and the Toledo Mountains, Central Iberian Zone, is documented here. The Lower Alcudian-Domo Extremeño Supergroup is subdivided, from bottom to top, into the conformable Guadiana (La Coronada and Sta. Mª de Zújar formations) and Campanario (Botija, Monroy and Orellana formations) groups. The supergroup contains biostratigraphically non-significant bacterial acritarchs and dubious fossils, but its Ediacaran age is constrained by detrital zircon analyses. This siliciclastic sedimentary package is unconformably overlain by either the siliciclastic-carbonate Ibor Group (Castañar, Villarta and Arrocampo formations) or the siliciclastic Cíjara Formation. The fossil content of the former group includes Sabelliditids, Vendotaenids, macrophytes, bioaccumulations and reefs rich in Cloudina, Sinotubulites, Protolagena and stromatolites and thrombolites, and a wide diversity of ichnofossils; whereas the Cíjara Formation has yielded bacteria attributed to Bavlinella and Palaeogomphosphaeria, and simple trace fossils (Gordia, Helminthoidichnites and treptichnids). The Ediacaran-Cambrian boundary, based on ichnofossils, lies at the base of the Arrocampo Formation and the uppermost part of the Cíjara Formation. In the Alcudia valley, the Ibor Group is subdivided into another three-fold, lithologically equivalent subdivision, known as the Tamujar, Hinojosas (rich in ichnofossils, such as treptichnids, Monomorphichnus, Psammichnites and Taphrelminthopsis) and Cabezarrubias (including Bergaueria and Planolites) formations. Another unconformity, intra-Fortunian in age, marks the tops of the Ibor Group and the Cíjara Formation, wich are subsequently overlain by the San Lorenzo Formation and some megabreccia beds, respectively. Overlying the slope-related Fuentes, Membrillar and Navalpino megrabreccia beds, the Terreneuvian-Cambrian Series 2, heterolithic Pusa Formation is subdivided into thre members, the middle one characterized by the record of phosphate ore deposits (e.g., the Fontanarejo Bed). The formation is shale dominated and has yielded the body-fossil Beltanelliformis and numerous ichnofossils (Monomorphicnus and Treptichnus; lower member), sponge spicules associated with thrombolites (middle member), and Scenella, trilobites, archaeocyaths and ichnofossils (Dactyloidites, Psammichnites, Rusophycus and Teichichnus; upper member). Where the megabreccia beds are absent, the Ibor Group is unconformably overlain by the San Lorenzo and Fuentepizarra formations, the latter containing phosphatic limestone interbeds rich in skeletonized microfossils, such as Anabarella, which represents the Fortunian-Cambrian Stage 2 boundary interval.

Cretaceous-Paleogene flysch represents the youngest formation in the Budva Zone. Although the Maastrichtian-Lower Eocene age of these rocks has been well documented in the literature, trace fossils are only mentioned as abundant and not described. In the present paper, only a small number of ichnotaxa from Mide locality has been described, including Lorenzinia carpathica (ZUBER), Nereites irregularis (SCHAFHAUT), Scolicia plana KSIĄŻKIEWICZ and Paleodictyon latum VIALOV & GOLEV. They confirm deepsea environment.

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The Campano-Maastrichtian Gombe Formation is located in the Gongola Basin of Upper Benue Trough and forms the north-south outcrop in western margin of the basin. The sediments were believed to have been deposited under conditions of deltaic, estuarine and shoreface environments. Ichnofossils or trace fossils some of localities within the Campano-Maastrichian Gombe Formation were studied with the aim of revisiting the paleoenvironmental significance and add to existing knowledge based. The study revealed two major types of ichnofacies, the Cruziana and Skolithos. Cruziana ichnofacies are the Thalassinoides and moderately common Planolites whilst the Skolithos ichnofacies elements are predominantly the Ophiomorpha's. However, the Ophiomorpha is a common trace fossil that is normally found in Mesozoic to Cenozoic sedimentary rocks deposited in either shallow or marginal marine environments. The Thalassinoides and Planolites ichnofossils may be found in both the marine and coastal facies of the Cretaceous sediments and this further suggest that the paleodepositional environment of the Campano-Maastrichian Gombe Formation as coastal and shallow marine deposited under higher and lower energy of the wave and tidal processes. [ABSTRACT FROM AUTHOR]

The present study aimed at performing a quantitative evaluation to propose a geoconservation plan to the São Domingos geosite, and, therefore, to contribute with feasible actions, to the preservation of this paleontological heritage. The study area is located in the district in the Itaguatins municipality, northern Tocantins state, Brazil. The studied geosite is characterized by the presence of track fossils. The tracks have been assigned to herbivorous dinosaurs, basal sauropods, which were living in the area during the first periods of the Cretaceous. The following aspects were quantitatively evaluated: risk of degradation and potential for the educational and touristic use of the area. All these aspects were quantitatively evaluated with the methodology described in the app web GEOSSIT, administered by the Companhia de Pesquisa de Recursos Minerais. The São Domingos geosite has a high scientific value, with a national relevance, a moderate potential of educational use, a low potential of tourist use, and a high risk of degradation. The site, with interest and paleontological value, has the potential to be used in all level educational activities at, and it is important it should be used for such activities. The elements of the geosite are currently in an advanced degree of degradation, and urgent measures are required to mitigate the erosive activities that affect the footprint-bearing surfaces and that gradually increase their erosion. [ABSTRACT FROM AUTHOR]

Trace fossils, representing ichnospecies Cubiculum ornatus, C. inornatus, Cubiculum isp., and Cuniculichnus variabilis as well as three indeterminate morphological categories (thin branching grooves A and B, furrows and circular chambers), are here recorded on vertebrate remains from the mid-Cretaceous (lower Cenomanian) of the 'Continental Intercalary' deposits in the Gara Samani locality (central Sahara of Algeria). Apart from thin branching grooves (A and B), which are thought to result from root etching, the bioerosion traces recorded on the bones comprise circular chambers and furrows, which represent pupation chambers of scavenging insects, most likely attributed to dermestid beetles. These trace fossils are identified and described for the first time from the Cretaceous of Algeria. They add new data to the trace-fossil assemblages previously reported from other Cretaceous successions of North Africa (e.g., the Kem Kem beds in Morocco). Sedimentological clues indicate a braided fluvial system environment. Taphonomic analysis suggests that the vertebrate remains were most likely subaerially exposed for a prolonged time prior to being transported and finally buried. Therefore, most of the studied borings are likely the result of dermestid beetle larvae feeding on dry bones on dry lands; other borings represent plant etchings produced after the bones were partially covered by, or completely buried, in sediments. [ABSTRACT FROM AUTHOR]

Organic-rich rocks of the Marcellus subgroup in the study area consist of a diverse suite of mudstone lithofacies that were deposited in distinct facies belts. Lithofacies in the succession range in composition from argillaceous to siliceous, calcareous, and carbonaceous mudstone. Heterogeneities in the succession occurs in the form of varying mineralogical composition, slightly bioturbated to highly bioturbated chaotic matrix, organic-rich and organic-lean laminae, scattered fossil shells in the matrix, and fossils acting as lamination planes. Lithofacies were deposited in three facies belts from the proximal to the distal zone of the depositional system. Bedded siliceous mudstone (BSM) facies occur in the proximal facies belt and consists of a high quartz content in addition to clay minerals and pyrite. In the medial part of the facies belt lies the laminated argillaceous mudstone (LAM), bedded calcareous mudstone (BCaM), and bedded carbonaceous mudstone (BCM). The size of detrital mineral grains in the lithofacies of the medial facies belt is larger than bedded argillaceous mudstone (BAM) of the distal facies belt, characterized by clay-rich matrix with occasional fossil shells and horizontally aligned fossils. Two types of horizontal traces and one type of fecal string characterize the proximal mud-stone facies, whereas only single horizontal trace fossil is found in the mudstones of the medial and distal facies belt. Parallel alignment of fossil shells and fossil lags in lithofacies indicate that bed-load transport was active periodically from the proximal source of the depositional system. Bioturbation has heavily affected all of the lithofacies and presence of mottled burrows as well as Devonian fauna indicate that oxic to dysoxic conditions prevailed during deposition. The deposition of this organic-rich mudstone succession through dynamic processes in an overall oxic to dysoxic environment is different from conventional anoxic depositional models interpreted for most of the organic rich black shales worldwide. Total organic content (TOC) varies from top to bottom in the succession and is highest in BCM facies. The brittleness index, calculated on the basis of mineralogy, allowed classification of the lithofacies into three distinct zones, i.e., a brittle zone, a less brittle zone, and a ductile zone with a general proximal to distal decrease in the brittle behavior due to a decrease in the size of the sediments.

Hollow tubular structures in subaqueously-emplaced basaltic glass may represent trace fossils caused by microbially-mediated glass dissolution. Mineralized structures of similar morphology and spatial distribution in ancient, metamorphosed basaltic rocks have widely been interpreted as ichnofossils, possibly dating to ∼3.5 Ga or greater. Doubts have been raised, however, regarding the biogenicity of the original hollow tubules and granules in basaltic glass. In particular, although elevated levels of biologically-important elements such as C, S, N, and P as well as organic compounds have been detected in association with these structures, a direct detection of unambiguously biogenic organic molecules has not been accomplished. In this study, we describe the direct detection of proteins associated with tubular textures in basaltic glass using synchrotron X-ray spectromicroscopy. Protein-rich organic matter is shown to be associated with the margins of hollow and partly-mineralized tubules. Furthermore, a variety of tubule-infilling secondary minerals, including Ti-rich oxide phases, were observed filling and preserving the microtextures, demonstrating a mechanism whereby cellular materials may be preserved through geologic time.