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The greatest relative changes in marine biodiversity accumulation occurred during the Early Paleozoic. The precision of temporal constraints on these changes is crude, hampering our understanding of their timing, duration, and links to causal mechanisms. We match fossil occurrence data to their lithostratigraphical ranges in the Paleobiology Database and correlate this inferred taxon range to a constructed set of biostratigraphically defined high-resolution time slices. In addition, we apply capture–recapture modeling approaches to calculate a biodiversity curve that also considers taphonomy and sampling biases with four times better resolution of previous estimates. Our method reveals a stepwise biodiversity increase with distinct Cambrian and Ordovician radiation events that are clearly separated by a 50-million-year-long period of slow biodiversity accumulation. The Ordovician Radiation is confined to a 15-million-year phase after which the Late Ordovician extinctions lowered generic richness and further delayed a biodiversity rebound by at least 35 million years. Based on a first-differences approach on potential abiotic drivers controlling richness, we find an overall correlation with oxygen levels, with temperature also exhibiting a coordinated trend once equatorial sea surface temperatures fell to present-day levels during the Middle Ordovician Darriwilian Age. Contrary to the traditional view of the Late Ordovician extinctions, our study suggests a protracted crisis interval linked to intense volcanism during themiddle Late Ordovician Katian Age. As richness levels did not return to prior levels during the Silurian—a time of continental amalgamation—we further argue that plate tectonics exerted an overarching control on biodiversity accumulation.

Lower–Middle Ordovician brachiopods are well known from the Central Andean Basin of Argentina and Bolivia, but relatively little data comes from its northern prolongation in the Altiplano and the Eastern Cordillera of Peru. Here we present information about brachiopods collected from the San José Formation (Fm) from several sections located at the northeast of the Apurímac River valley in the surroundings of Kimbiri city in the Eastern Cordillera. From northwest to southeast the sections and their locations are: Libertad, in the mountain trail between this hamlet and the city of Pichari; Catarata and Nueva Alianza, in the mountain trail between Oroya and the last hamlet; and Kimbiri (K), in the trail parallel to the Kashiroveni stream north of the village of Kimbiri Alto. In these localities the San José Fm lies unconformably on Neoproterozoic rocks, reaching the maximum thickness of about 700 m. This shale-dominated formation comprises a biostratigraphically almost complete succession of the upper Tremadocian to lower Sandbian strata and contains graptolites, trilobites, brachiopods, molluscs, echinoderms and ostracods, as well as some conodonts and other microfossils. The upper part of the San José Fm is unconformably overlain by a thick sandy and diamictic succession, known as the Kimbiri Fm. About 30 fossiliferous levels have been found in the San José Fm in the Kimbiri section, nine of which contain identifiable brachiopod remains and most of them are precisely constrained by graptolites. The lowermost brachiopod-bearing fossiliferous bed (K-03) occurs about 115 m above the base of the section, being assigned to the Baltograptus minutus Graptolite Biozone (GB) (upper Floian, Fl3) and containing a single specimen of a small indeterminate orthid. Stratigraphically higher in the formation, the next two assemblages in the beds K-07 and K-11, containing also upper Floian graptolites, provided Paralenorthis immitatrix. This species was originally described from the San Lucas locality of the Bolivian Eastern Cordillera, from rocks tentatively correlated with the upper Floian–lower Darriwilian. It also occurs in the San José Fm in the Inambari River section located in the Peruvian Eastern Cordillera, ca. 250 km to the east of Kimbiri, in the interval corresponding to the upper Floian–Dapingian(?). Sandstones occurring about 40 m higher, in the fossiliferous bed K-12, yielded a slightly more diverse assemblage composed of Mollesella planidorsalis, P. immitatrix and an indeterminate orthoid. M. planidorsalis is characteristic of the Loma del Kilómetro Member of the Suri Fm in the central Famatina Range, correlated with the Floian to middle(?) Dapingian based on the occurrence of conodonts of the Prioniodus elegans, Oepikodus evae and Baltoniodus navis conodont biozones. Less than 10 m higher, the sandstones of the bed K-13 only yielded two poorly preserved unidentifiable specimens of Ahtiella. Slightly higher, in the bed K-15 just below the Holmograptus lentus or Didymograptus artus GB, a more diverse assemblage is dominated by a new species of Phragmorthis as well as by P. immitatrix; additionally it contains few specimens of Ahtiella zarelae and a new species of Dalmanella. A. zarelae was exclusively reported from the San José Fm at the Inambari River section. From this level upwards, the brachiopod assemblages become homogeneous in the Kimbiri section (but dominance changes) and co-occur with graptolites of the Didymograptus artus GB (middle Darriwilian, Dw2). For instance, in the bed K-16 a new species of Dalmanella becomes predominant. The bed K-17 yielded only P. immitatrix. The highest sampled bed with brachiopods (K-21) is dominated by A. zarelae and a new Phragmorthis species, P. immitatrix is still present and unidentifiable specimens of Christiania occur. This particular assemblage occurs about 30 m below shales of the Nemagraptus gracilis GB (lower Sandbian, Sa1). The brachiopod occurrences cited above improve the knowledge of the late Early Ordovician–early Middle Ordovician faunas of the Peruvian Eastern Cordillera and emphasize strong connections of this region with the Bolivian Eastern Cordillera and Argentinian Famatina Range during that epoch. Additionally, the occurrence of Phragmorthis suggests connections with several low-latitude terranes and palaeocontinents, such as the Mayo Terrane, Laurentia, Baltica, and South China.

Naturtejo UNESCO Global Geopark (Portugal) area includes deposits from the Neoproterozoic to the Quaternary. Despite its limited exposure area in major Variscan folded structures, the Ordovician series hosts some of its most famous geological heritage features, such as the Penha Garcia Ichnological Park. The Upper Ordovician of the Central Iberian Zone is still far from being as well-understood as it is in other areas. Extensional tectonics, magmatism, global eustatic and climatic changes generated a great variability of sequences in a reduced geographical area. The Upper Ordovician of the Naturtejo region, often considered poorly represented, is here demonstrated to have a great potential and to be more complete than previously assumed. New stratigraphic and paleontologic data are presented for the three Upper Ordovician-bearing structures within Naturtejo: Fajão-Muradal, Vila Velha de Ródão and Penha Garcia synclines. Remobilized upper Katian fossiliferous clasts were found for the first time within the Hirnantian Casal Carvalhal from the Fajão-Muradal Syncline and a new fossil site is added to the Orvalho GeoTrail. In the Vila Velha de Ródão Syncline, the Barroca da Senhora stream fossil site constitutes a new geosite within the protected area of Portas de Ródão Natural Monument, presenting the most complete Upper Ordovician sequence of this structure. Finally, the stratigraphic and paleontologic record of the Vale Feitoso estate offers all the conditions to propose a new theme geotrail, diversifying the tourism in the Monfortinho village (Penha Garcia Syncline).

Middle Ordovician successions occur at Naturtejo UNESCO Global Geopark in five Variscan-folded, kilometer- to tens of kilometer-long structures. Four of them revealed to be fossiliferous in the different recognized lithostratigraphic units, middle-to-uppermost Darriwilian in age, with particular emphasis for Brejo Fundeiro (Oretanian regional chronostratigraphic stage) and Fonte da Horta (Dobrotivian regional stage) formations. Recent paleontological and biostratigraphic works have detected most of the previously recorded and new fossil sites, improving the Middle Ordovician biostratigraphy of this region and updating the knowledge of its fossil assemblages, which are fairly more diverse than previously considered. The good preservation of the fossils and their relevance to understanding the climax of the Global Ordovician Diversification Event at high paleolatitude shallow marine environments, as well as the protection or identification of some of the fossil sites as UNESCO Geopark’ geosites, make certain their interpretation and use in already existing geotrails and new interpretation centers and school programs.

The lower strata of the Umachiri Formation from the Altiplano of southeast Peru have yielded a brachiopod-dominated assemblage, containing representatives of the brachiopod superfamilies Polytoechioidea, Orthoidea, and Porambonitoidea, as well as subsidiary trilobite and echinoderm remains. Two new polytoechioid genera and species, Enriquetoechia umachiriensis new genus new species and Altiplanotoechia hodgini n. gen. n. sp. Colmenar in Colmenar and Hodgin, 2020, and one new species, Pomatotrema laubacheri n. sp., are described. The presence of Pomatotrema in the Peruvian Altiplano represents the occurrence at highest paleolatitude of this genus, normally restricted to low-latitude successions from Laurentia and South China. Other polytoechioids belonging to Tritoechia (Tritoechia) and Tritoechia (Parvitritoechia) also occur. Identified species of orthoids from the genera Paralenorthis, Mollesella, and Panderina? occur in the Peruvian Cordillera Oriental and in the Argentinian Famatina Range. The only porambonitoid represented is closely related to Rugostrophia latireticulataNeuman, 1976 from New World Island, interpreted as peri-Laurentian. These brachiopod occurrences indicate a strong biogeographic affinity of the Peruvian Altiplano with the Famatina and western Puna regions, suggesting that the brachiopod faunas of the Peruvian Altiplano, Famatina, and western Puna belonged to a well-differentiated biogeographical subprovince during the Early–Middle Ordovician on the margin of southwestern Gondwana. Links with peri-Laurentian and other low-latitude terranes could be explained by island hopping and/or continuous island arcs, which might facilitate brachiopod larvae dispersal from the Peruvian Altiplano to those terranes across the Iapetus Ocean. Brachiopods from the lower part of the Umachiri Formation indicate a Floian–?Dapingian age, becoming the oldest Ordovician fossils of the Peruvian Altiplano.

A diverse crinoid fauna is described from the Upper Ordovician (Katian) Fombuena Formation from the eastern Iberian Chains of Spain. New crinoids include the diplobathrid camerates Fombuenacrinus nodulus n. gen. n. sp., Goyacrinus gutierrezi n. gen. n. sp., Dalicrinus hammanni n. gen. n. sp., and Ambonacrinus decorus n. gen. n. sp.; the monobathrid camerate Eopatelliocrinus hispaniensis n. sp.; and the cladid Picassocrinus villasi n. gen. n. sp. A new occurrence of Heviacrinus melendezi Gil Cid, Domínguez Alonso, and Silván Pobes, 1996 is also documented from the Castillejo Formation (Darriwilian, Middle Ordovician) from the eastern Iberian Chains of Spain. The Fombuena Formation comprises a Gondwanan crinoid assemblage from a high paleolatitude and has the highest crinoid diversity of any currently known Katian Gondwanan fauna. This assemblage is compared to other Katian age faunas around the globe, and its paleobiogeographic implications are discussed.

The Upper Ordovician (Katian–Hirnantian) brachiopods of Tafilalt, eastern Anti-Atlas, are locally abundant, diverse and well preserved, providing a near-continuous record of faunal change on a high-latitude siliciclastic-dominated platform. A chronostratigraphic framework, based on brachiopod distribution and preservation in shell accumulation events and integrated with sequence stratigraphy, has been generated for the Katian interval, which has allowed correlation with the chitinozoan-based chronostratigraphic and sequence-stratigraphic framework erected for the central Anti-Atlas. In Tafilalt, two Katian (transgressive–regressive) composite depositional sequences, c. 60 and 170 m thick and related to third-order fluctuations in sea level, were unaffected by Hirnantian glaciogenic erosion. They were deposited on a mixed platform with a bryonoderm association dominated by brachiopods, bryozoans and echinoderms. Brachiopods developed in high-energy inner shelf areas, whereas bryozoans (mainly trepostomates and fenestrates) and pelmatozoans (cystoids and crinoids) dominated in low-energy outer shelf areas. Brachiopod accumulations mark distinct event surfaces, such as lag and event concentrations, hydraulic simple and composite concentrations related to transgressive surfaces, and hiatal condensed concentrations marking maximum flooding surfaces. The taphonomic condensation displayed by the Hirnantian Alnif Member, which onlaps the erosive base of glaciogenic tunnel channels, is explained as reworking and resedimentation of allochthonous, robust, biogenic hard parts sourced from the underlying (Katian) Ktaoua Group.

The end-Ordovician mass extinction, linked to a major glaciation, led to deep changes in Hirnantian–Rhuddanian biotas. The Hirnantia Fauna, the first of two Hirnantian survival brachiopod-dominated communities, characterizes the lower–mid Hirnantian deposits globally, and its distribution is essential to understand how the extinction took place. In this paper, we describe, illustrate, and discuss the first macrofossiliferous Hirnantia Fauna assemblage from Belgium, occurring in the Tihange Member of the Fosses Formation at Tihange (Huy), within the Central Condroz Inlier. Six fossiliferous beds have yielded a low-diversity, brachiopod-dominated association. In addition to the brachiopods (Eostropheodonta hirnantensis, Plectothyrella crassicosta, Hirnantia sp., and Trucizetina? sp.), one trilobite (Mucronaspis sp.), four pelmatozoans (Xenocrinus sp., Cyclocharax [col.] paucicrenulatus, Conspectocrinus [col.] celticus, and Pentagonocyclicus [col.] sp.), three graptolites (Cystograptus ancestralis, Normalograptus normalis, and ?Metabolograptus sp.), together with indeterminate machaeridians and bryozoans were identified. The graptolite assemblage, from the Akidograptus ascensus-Parakidograptus acuminatus Biozone, indicates an early Rhuddanian (Silurian) age, and thus, an unexpectedly late occurrence of a typical Hirnantia Fauna. This Belgian association may represent an additional example of relict Hirnantia Fauna in the Silurian, sharing characteristics with the only other known from Rhuddanian rocks at Yewdale Beck (Lake District, England), although reworking has not been completely ruled out. The survival of these Hirnantian taxa into the Silurian might be linked to delayed post-glacial effects of rising temperature and sea-level, which may have favored the establishment of refugia in these two particular regions that were paleogeographically close during the Late Ordovician–early Silurian.

The first report of the Hirnantia high-latitude peri-Gondwanan Fauna from Portugal (Upper Ordovician, Ribeira do Braçal Formation) is presented here. The described macroassemblages are fairly diverse containing fossils of brachiopods, trilobites, echinoderms, machaeridians, and ostracodes. Among the brachiopods, the most abundant is Mirorthis mira. Plectothyrella cf. P. libyca, Paromalomena cf. P. polonica, Plectoglossa? sp., and a small indeterminate discinoid are also present. The trilobites are represented by abundant sclerites of Mucronaspis cf. M. mucronata, and an isolated cranidium and pygidium assigned to Flexicalymene. The occurrence of Mucronaspis and Flexicalymene represents the first record of these genera in Portugal. Echinoderms are dominant in the basal bed of the formation; the columnal plates tentatively ascribed to morphogenus Pentagonocyclicus are the most abundant, followed by the echinosphaeritids. Abundant disarticulated machaeridian plates, of the genus Plumulites, associated with trilobites are present in one of the localities. Ostracodes were found in one single locality and have been assigned tentatively to the genus Herrigia. Ramose and massive bryozoans also occur in the assemblage. This new macrofossil assemblage supports the assignment of an Hirnantian age for the Ribeira do Braçal Formation. Most of the brachiopod species and the dalmanitid Mucronaspis are commonly present in Hirnantian deposits globally, but the presence in the assemblage of a brachiopod close to Plectothyrella libyca, a cold-water species, previously reported only from the Hirnantian of Libya and Morocco, is noticeable. This strengthens the case for a high latitudinal setting of the present-day territory of the Portuguese Central Iberian Zone during the Late Ordovician.

Due to its potential to develop new added value products, a staggering number of nanoparticles (NPs) is already available on the market. Moreover, this increase is expected to continue in the future. However, there is a lack of knowledge on the level of exposure to nanoparticles, and the information related to possible adverse health effects is scarce. Furthermore, there is very little studies concerning the effect of risk management measures (RMMs) on the levels of exposure to nanoparticles at workplaces, compared to the number of exposure situations that can be distinguished. This study focuses on 5 case studies covering different types of materials, assessing the effectiveness of targeted mitigation strategies applied during the production process. Customized mitigation measures were applied in each industrial scenario to minimize exposure levels. The effects on the particle concentration levels using source enclosure, partial or full, combined with local exhaust ventilation systems (LEVs), was evaluated to generate new knowledge to support the definition of informed safe by process design approaches when dealing with NPs. This study demonstrates that technological advancements can significantly reduce work-related exposures. The findings underscore the importance of tailored mitigation measures due to the diverse range of potential sources and activities in industrial scenarios.