The Eocene limestones exposed around the village of Bolca, northern Italy, have provided some of the most complete and wellpreserved marine assemblages of the Cenozoic. The fossils of these deposits, especially the famous fossil fishes, are known for more than four centuries and document tropical marine shallow-water ecosystems of the western Tethys, representing a spectacular snapshot of Eocene marine life. The one-day palaeontological field trip presented herein constitutes a deep immersion into the early Cenozoic marine tropical biodiversity of the western end of the Tethys Ocean. The focus of this field trip is therefore to provide a general overview of the outstanding organism diversity of the two main sites of the Bolca Lagerst & auml;tten, Monte Postale and Pesciara, and to show their stratigraphic and palaeoenvironmental setting. The field trip starts with a visit to the Museo Civico di Storia Naturale, Verona, which includes the most important collection of Bolca fossils. Then, the second stop shows the Monte Postale stratigraphic succession, and the third stop illustrates the celebrated Pesciara site, exploited for the collection of spectacular fossils since the 16th century.

The shallow and deep water sediments and fossils of Tuscany have been studied for centuries, but uncertainties still exist regarding the chronostratigraphy and the tectonic regime controllingthe basin development. In an overall extensional tectonic regime, related to the opening of the Tyrrhenian Sea, Neogene-Quaternary Tuscan basins have been interpreted either as bowl-shaped basins evolving into graben bounded by normal faults, or as thrust-top basins (broken foreland basins). To better understand the dynamics of Tuscan basin infill, we present an integrated stratigraphic study of a succession exposed at the Belvedere waste facility near Legoli (municipality of Peccioli, Pisa, Italy), in the Valdera-Volterra basin (VVB). The section consists of clays and sandy clays interrupted by two sandy intervals and topped by a mainly sandy succession. We reconstruct depositional dynamics through sedimentary facies analysis and palaeoecology, and we use biostratigraphy and palaeomagnetism for chronostratigraphic assignment of the succession. The bio-magnetostratigraphic data indicate that the section falls at the Zanclean/ Piacenzian transition, encompassing the Gilbert reversed chron (C2Ar) to the Gauss (C2An.3n) normal chron transition dated 3.6 Ma. Our study constrains the sedimentary infill of the VVB at Legoli between the latter part of the Zanclean and the early Piacenzian, at the onset of the first signs of a Northern Hemisphere glaciation. The section shows a shallow tilting towards the WNW, tilting that decreases towards the top of the section, pointing to tectonic control on deposition at a time of increased sediment accommodation due to basin subsidence. Our results indicate that this sector of the VVB, interpreted as a thrust-top basin under a crustal shortening acme during the Messinian, underwent tectonic subsidence controlled by normal faults during the Piacenzian.

This study delves into the rich collections of Pliocene and Pleistocene fossil vertebrate remains housed in the Museo di Storia Naturale dell'Universitd di Firenze, tracing their origins back to the 17th Century with notable acquisitions by Grand Duke Ferdinando II and Cardinal Leopoldo. Comprising approximately 15,000 fossil remains primarily sourced from the Valdarno region, these collections offer invaluable insights into palaeontological history and the evolution of past ecosystems. The Museum's commitment to excellent curation of these specimens, coupled with its promotion of research initiatives, has significantly enhanced our understanding of Pliocene and Pleistocene vertebrate palaeontology. Through ongoing research efforts, the Museum continues to deepen our knowledge of past climates, environments, and the evolution of life on Earth. This study aims to underscore the significance of these collections, emphasising their pivotal role in advancing scientific knowledge. Furthermore, it pays homage to the visionary leadership of past directors Augusto Azzaroli and Danilo Torre, whose contributions have been instrumental in expanding the Museum's collections and fostering groundbreaking research. The "Valdarno Pliocene and Pleistocene Mammals" collection stand as a testament to the enduring legacy of scientific inquiry and discovery, enriching our understanding of the natural world and has just appointed by the International Commission on Geoheritage as Geoheritage Collection of global importance because of its particularly high scientific, historical and educational relevance for geological sciences.

The Late Miocene was a period of major paleogeographic, climatic and biotic changes for the Mediterranean due to the restriction of the marine gateway to the Atlantic, which culminated to the Messinian Salinity Crisis (MSC), and the ongoing global climatic cooling. The Late Miocene ecological crisis very likely affected biodiversity of bivalves living in the Mediterranean during that time. In this study, we investigate the consequences of the Messinian Salinity Crisis and its preconditioning phase for the evolution of functional diversity of the Mediterranean bivalve fauna. The biodiversity of bivalves is quantified for the Tortonian, the pre-evaporitic Messinian and the Zanclean of the Mediterranean using the functional richness index, by considering the following bivalve species traits: lifestyle, depth range, maximum adult size, trophic role and substrate affinity. The analysis is based on a recently compiled dataset containing the updated fossil record of the Mediterranean bivalves for this time interval. The traits of the species in this dataset is obtained from online open-access databases and the literature. Our results support a decrease in the functional diversity of bivalves in the Mediterranean from the Tortonian to the Early Messinian and a full recovery in the Early Pliocene.

The species richness of major clades and functional groups among gastropods, a key element of Modern Evolutionary Fauna (MEF), underlines the dominant role of carnivorous Caenogastropoda and Heterobranchia, including small ectoparasites and micrograzers, at modern tropical latitudes. Neogastropoda are active predators that radiated in the Cretaceous, but their early Mesozoic MEF roots are poorly understood. The escalation hypothesis emphasises prey–predator interactions as gastropods’ macroevolutionary drivers during the Mesozoic Marine Revolution but overlooks the significance of highly diversified smaller forms. The tropical fossil record of the Permian–Triassic mass extinction (PTME) and the Triassic rise of MEF suggests that non-carnivorous species dominated gastropod fauna immediately before and after the PTME: Permian micrograzers mainly fed on sponges and waned during the rise of MEF, while ectoparasites and micrograzing carnivores diversified starting from the Ladinian period. Patterns of gastropod species richness, size, and form, the fossil record of reef builders and other benthic invertebrates, and an analysis of stem neogastropods jointly suggest a Middle Triassic revolution of small-sized gastropods, triggered by the emergence of scleractinian corals and the diversification of echinoderms. Habitat heterogeneity and new food sources offered niches for the early radiation of modern gastropod clades.

Haliotis Linnaeus, 1758, a commercially important gastropod, is the only known genus in the family Haliotidae (Mollusca, Vetigastropoda, or abalone) worldwide. Its poor Cenozoic record and high intraspecific variability resulted in different interpretations of nomenclature, impeding a robust species-level taxonomy and biogeographic history. Among the best-studied forms, three subspecies of H. tuberculata Linnaeus, 1758 currently inhabit the temperate waters of the Mediterranean and the eastern Atlantic. New findings in the Pliocene of Tuscany (Italy) are presented here, and the taxonomy of the European record is revised. On the basis of a multivariate analysis of shell morphometrics for the first time applied to the study of fossil abalones, and consistent with the chronostratigraphic and geographic framework, H. plioetrusca n. sp. is introduced and H. volhynica Eichwald, 1829 and H. lamellosoides Sacco, 1897 are reinstated as valid species. Some recently described forms from the Pliocene of Spain are placed in synonymy with H. lamellosoides. Haliotis ovata Michelotti, 1847 is proposed as the ancestral taxon of modern H. tuberculata , via H. lamellosoides . This lineage diversified in the subtropical/warm temperate Pliocene Mediterranean, represented by H. lamellosoides , H. bertinii Forli et al., 2003 and H. plioetrusca . The progressive global cooling starting at around 3.0 Ma is associated with the appearance of H. tuberculata at temperate latitudes. H. plioetrusca is not known from younger strata, whereas H. bertinii survived into the Calabrian. UUID: http://zoobank.org/7c2f2258-2574-4976-a2f5-804c54c86679

The Late Miocene flora of Montebamboli in Tuscany was described in the classical work of Gaudin and Strozzi from the second half of the 19(th) th century. Since then, it has never been revised. The Montebamboli locality is most famous for the occurrence of the hominoid Oreopithecus bambolii and hence a reappraisal of its flora can shed new light on the environments in which this hominoid thrived. The revised palaeobotanical record of Montebamboli suggests that the leaf assemblage is dominated by elements typical of riparian and swamp forest ( Alnus , Acer, Salix, Platanus, etc.). The palm Sabal, which is represented by numerous fossil leaves, is also characteristic of riparian vegetation. The poor record of the mesophytic vegetation thriving on well-drained soils, further away from the zone of deposition, is represented by Fagus (beech) and an enigmatic chestnut-like oak ( Quercus gigas). Along with the previously published palynological record, including additional ferns, Cyperaceae, and Zingiberaceae, it appears that food sources for Oreopithecus would have comprised a wealth of tubers, fruits (nuts and acorns of beech, oak and hazelnut), and drupes of Sabal. The flora of Montebamboli represents an impoverished version of a typical Late Miocene flora of the western and central parts of the northern Mediterranean region. The composition of the flora supports the idea that the Montebamboli lignites and the adjacent Baccinello lignites are coeval.

We describe a high-diversity silicified assemblage of marine molluscs (Pelsa-Vazzoler Lagerst & auml;tte) from the upper Ladinian of the Agordo Dolomites (northeastern Italy). New data on the Triassic rebound, after the end-Permian mass extinction, constrain it to an interval of relatively stable climatic conditions. This Lagerst & auml;tte, in the Sciliar Formation, yields a structure comparable to the famous lower Carnian San Cassiano Lagerst & auml;tte and suggests that the radiation of benthic molluscs may have occurred as early as the late Middle Triassic. We classified more than 4800 Cassian-type molluscs, measuring abundance distributions of 109 species, including one new family (Rhaetidiidae), three new genera (Pelsia, Gaetania, Agordozyga) and 21 new species: Grammatodon egortinus, Modiolus friesenbichlerae, Myoconcha busattae, Schizogonium letiziae, Predazzella? monarii, Eucycloscala nitida, Tricolnaticopsis elongatus, Cortinella stricta, Triadoskenea alpicornu, Trachynerita tenuicostata, Coelostylina civettae, Gaetania coronata, Agordozyga caprina, Euthystylus dincae, Zygopleura elongata, Diatrypesis agordina, Cryptaulax pelsae, Pseudoscalites karapunari, Promathildia gracile, Camponaxis ladinica and Striactaeonina ingens. In this fauna, associated with tropical carbonate platforms, epifaunal filter-feeding bivalves adopted new antipredatory features and gastropods conquered new ecospace, including parasitism and microcarnivory on sponges and scleractinian corals. Small size was an advantage in an ecosystem of small, isolated patch reefs. This is how, where and when caenogastropod and heterobranch snails (groups that today dominate global marine diversity) began their rise in the marine benthos. The origins of some evolutionary innovations that are key to our understanding of the time and place of the Mesozoic Marine Revolution, are therefore pushed back to the Middle Triassic.

The revision of fossil specimens mainly collected in the sixties of the last century and today hosted at the Museo di Storia Naturale of Pisa allowed to update the taxonomy of Lower Tortonian bivalves and some gastropods of the Ponsano Sandstone, cropping out in southern Tuscany in the Pisa and Siena provinces. The stratigraphy of the original successions was reconstructed and quantitative data were estimated by counting museum specimens and by transforming literature semiquantitative data into quantitative ones. The paleoecology of three successive main assemblages has been defined by measuring the relative abundance of bivalves and the transgressive-regressive trend of the succession in the type area (previously known from sedimentary and micropaleontological data) has been confirmed for the first time based on the macrofauna.

Understanding deep-time marine biodiversity change under the combined effects of climate and connectivity changes is fundamental for predicting the impacts of modern climate change in semi-enclosed seas. We quantify the Late Miocene-Early Pliocene [11.63 to 3.6 million years (Ma)] taxonomic diversity of the Mediterranean Sea for calcareous nannoplankton, dinocysts, foraminifera, ostracods, corals, molluscs, bryozoans, echinoids, fishes, and marine mammals. During this time, marine biota was affected by global climate cooling and the restriction of the Mediterranean's connection to the Atlantic Ocean that peaked with the Messinian salinity crisis. Although the net change in species richness from the Tortonian to the Zanclean varies by group, species turnover is greater than 30% in all cases, reflecting a high degree of reorganization of the marine ecosystem after the crisis. The results show a clear perturbation already in the pre-evaporitic Messinian (7.25 to 5.97 Ma), with patterns differing among groups and subbasins.

19thcentury th century scientists concerned with the interpretation of well and outcrop data collected during mining activities in southern Tuscany (Italy) agreed on the isochrony of the Montebamboli, Casteani, Ribolla and Montemassi Late Miocene black lignite and fetid limestone. The associated faunal and floral remains from the four localities, including the primate Oreopithecus bambolii Gervais, 1872, first described from a fossil collected at Montebamboli, were similarly interpreted as coeval. A second wave of scientists reconsidered the Montebamboli fossils during the 1950s, expanded the research to the Baccinello area, further south, and interpreted the Late Miocene record of Tuscany to signal instances of phyletic transitions among insular species. On the basis of palaeontological data, without discussing the correlations emerged during mining activities, the Montebamboli fauna was interpreted as a fauna younger than the fauna associated with the Casteani and Baccinello black lignite. The new point of view justified a palaeobiogeographic scenario characterised by multiple immigrations from the continental mainland to an insular Tuscan bioprovince, and from there to Sardinia, where an analogous Late Miocene Oreopithecus-associated-associated insular fauna has been meanwhile studied. Based on old and new field data, the isochronic interpretation of the Montebamboli and Casteani black lignite is here resumed and an alternative palaeobiogeographic scenario is proposed, in the attempt to minimise inconsistencies that stem from the more recent school of thought. The alternative scenario points to a single phase of Tusco-Sardinian insularism bracketed between two intervals of faunal interchange when Tuscany and Sardinia came in contact with the continental mainland. Insularism took place within a single large island, or a single larger archipelago comprising southern Tuscany, Corsica and Sardinia, existing before and shortly after the opening of the Tyrrhenian Sea during the Tortonian.

Massive salt accumulations, or salt giants, have formed in highly restricted marine basins throughout geological history, but their impact on biodiversity has been only patchily studied. The salt giant in the Mediterranean Sea formed as a result of the restriction of its gateway to the Atlantic during the Messinian Salinity Crisis (MSC) 5.97 to 5.33 million years ago. Here, we quantify the biodiversity changes associated with the MSC based on a compilation of the Mediterranean fossil record. We conclude that 86 endemic species of the 2006 pre-MSC marine species survived the crisis, and that the present eastward-decreasing richness gradient in the Mediterranean was established after the MSC.

Here we apply a sclerochronological approach to reconstruct the life-history of two stenohaline bivalves of the family Pectinidae, Gigantopecten latissimus and Pecten jacobaeus from the Pliocene of Italy. The specimens come from the locality of Torrita di Siena (Siena-Radicofani Basin, Tuscany), dated to the late Zanclean-Piacenzian with nannoplankton biostratigraphy and Sr-isotope stratigraphy. After measuring the width of micro-growth increments and verifying that the shells were not diagenetically altered, we sampled them at high resolution for carbon and oxygen stable isotopes. delta C-13 and delta O-18 shell values allowed to distinguish between specimens that lived above or below the thermocline. Those influenced by surface waters indicate temperatures (for delta O-18(seawater) = 1.5 parts per thousand) with winter minima of 16-18 degrees C and summer values up to 28-29 degrees C, close to present temperature conditions in the tropical west-African climate belt. In line with this, we found that the two species had similar seasonal growth patterns, with faster growth during colder months and summer slowdown, a typical adaptation of bivalves of tropical affinity suffering from summer temperature extremes. Despite this similar adaptation, G. latissimus, with large and heavy shells (length up to 30 cm) became extinct around 3.0 Ma, while the smaller P. jacobaeus survived Plio-Pleistocene cooling. Different growth rates between the two species and, therefore, different metabolic costs, might explain such differential response, together with differences in reproduction strategies. Habitat loss and fragmentation, due to the decrease of shelf margins and organogenic substrates caused by cooling and sea level fall, are abiotic factors that could have also contributed to the extinction of G. latissimus. P. jacobaeus adaptation to live across a larger bathymetric range, which indicates the ability to thrive in a wider range of temperatures, most likely played a role in its survival. Further studies, including more specimens across multiple localities, will help verifying these hypotheses.

The Mediterranean Sea is recognized as a hotspot of marine biodiversity. Analysing its past biodiversity can help in understanding species' response to climate change. We built a species-level dataset of bivalve occurrences across the Zanclean-Calabrian interval, a time characterized by significant changes in climate, and by bivalve extinctions. The dataset includes more than 400 species distributed from the eastern to the western Mediterranean Sea. We measured changes in richness and turnover through time, for the entire dataset, and for different palaeoenvironments and combinations of tiering and feeding categories to test if specific environmental conditions and different lifestyles were correlated to species extinction or survival through time. We also compared niche breadth, geographical range size, and species abundance of extinct and extant species, to test which of these parameters potentially affected extinction risk. Our results confirm a loss of biodiversity between 3 Ma and the Early Pleistocene, although this loss was less intense and more gradual than previously estimated. We also found significant differences in niche breadth and geographical range size between extinct and extant species. Suspension feeders lost a higher proportion of species and suffered a higher reduction of geographical range compared to infaunal deposit feeders. Species loss was more protracted and higher on the shoreface than on the shelf, which is probably related to the reduction of shallow-water vegetated environments and to the disaggregation of heterozoan carbonate ramp habitats with cooling and sea-level drop at the onset of the northern hemisphere glaciation.

The Messinian salinity crisis and its precursor events have been the greatest environmental perturbation of the Mediterranean Sea to date, offering an opportunity to study the response of marine ecosystems to extreme hydrological change and a large-scale biological invasion. The restriction of the marine connection between the Mediterranean and the Atlantic Ocean resulted in stratification of the water column and high-amplitude variations in seawater temperature and salinity already from the early Messinian. Here, we present a unified and revised marine fossil record of the Mediterranean (10.5281/zenodo.13358435, Agiadi et al., 2024) that covers the Tortonian stage, the pre-evaporitic Messinian stage, and the Zanclean stage and encompasses 23 032 occurrences of calcareous nannoplankton, dinoflagellates, foraminifera, corals, ostracods, bryozoans, echinoids, mollusks, fishes, and marine mammals. This record adheres to the FAIR principles, is updated in terms of taxonomy, and follows the currently accepted stratigraphic framework. Based on this record, knowledge gaps are identified, which are due to spatiotemporal inconsistencies in sampling effort and the distribution of sedimentary facies, as well as the inherent differences in the preservation potential between the groups. Additionally, sampling bias in old records may have distorted the record in favor of larger, more impressive taxa within groups. This record is now ready to be used to answer both geological and biological questions about the Mediterranean Sea and beyond and is amendable when new fossil data are brought to light.

The Pliocene fossiliferous succession of the Volterra hill, a prominent place in Tuscany, Italy and, since the Renaissance, the site of important archaeological finds of the ancient Etruscan civilization, has formed the object of enquiry over six centuries of research on the inner nature of the Earth system. The works of Restoro d'Arezzo, Leonardo da Vinci, Nicolaus Steno, Giovanni Targioni, Nicolas Desmarest, Giambattista Brocchi, Alexandre Brongniart and Charles Lyell testify to the early recognition through fieldwork that those strata with seashells had formed at the bottom of the sea. This interpretation served different approaches to knowledge. Restoro, Leonardo and Steno, spanning nearly four centuries in the history of science (1282-1669), including the 'Copernican Revolution' and the start of the Modern Age, relied also on textual sources and trusted a speculative model of the Earth's interior, so that at Volterra they focused on vertical movements of the earth-water system. The authors of the eighteenth and nineteenth centuries abandoned pre-built young-Earth models and emphasized the geography of ancient Tuscany. Brocchi, Brongniart and Lyell promoted the taxonomic use of seashells to correlate rocks across Europe. This place deserves higher standards of valorization to promote understanding of the history and sociology of ideas.

Physical connectivity between marine basins facilitates population exchange and hence controls biodiversity. The Mediterranean Sea is a semi-restricted basin with only a small two-way connection to the global ocean, and it is a region heavily impacted by climate change and biological invasions today. The massive migration of non-indigenous species into the basin through the Suez Canal, driven and enabled by climate warming, is drastically changing Mediterranean biodiversity. Understanding therefore the origin and cause(s) of pre-existing biodiversity patterns is crucial for predicting future impacts of climate change. Mediterranean biodiversity exhibits a west-to-east decreasing gradient in terms of species richness, but the processes that resulted in this gradient have only been hypothesized. By examining the fossil record, we provide evidence that this gradient developed 5.33 million years ago at the end of the Messinian Salinity Crisis, and it was therefore caused by the re-population of the basin by marine species with a dominating western source at the Mediterranean–Atlantic gateway.

Abstract Conservation palaeobiology informs conservation and restoration of ecosystems by using the fossil record to discriminate between baseline and novel states and to assess ecosystem response to perturbations. Variability in the time-scale of palaeobiological data can generate patterns that either exaggerate or mute the magnitude of biotic changes. We identify two approaches that remedy the challenges associated with the mixing of baseline and post-impact states and with the transformation of the stratigraphic depth to time. First, combining surface death assemblages with both (1) fossil assemblages preserved in the subsurface historical layers and (2) living assemblages can better resolve the nature of ecosystem shifts than within-core surveys or live–dead analyses alone. Second, post-mortem age distributions of skeletal particles and their preservation states are not only informative about stratigraphic resolution and time averaging of death assemblages but also about the timing of changes in abundance of skeletal producers. High abundance of the youngest age cohorts in surface death assemblages is a null expectation of disintegration and burial dynamic. When this dynamic is accounted for, age distributions of benthic invertebrates from Holocene sediments often reveal high volatility, prolonged turn-offs in production or pervasive regime shifts that are obscured in the raw stratigraphic record.

Abstract The mid-Piacenzian Warm Period (mPWP: 3.3–3.0 Ma) is the most recent geological analogue of ongoing climate change and has been the subject of considerable interest for numerical models of the climate system. To verify the effect of the mPWP on diversity and temporal turnover of marine benthic communities, we evaluated changes in species-level abundance and the composition of Mediterranean Pliocene molluscs prior, during and after the mPWP. The Pliocene onshore–offshore gradient in species composition did not change during the mPWP (and continued basically unchanged up to the present day in the Mediterranean Sea), with most dominant species occupying the same rank in a given environment. During the mPWP, species evenness generally increased towards offshore environments. Within the three time intervals, temporal similarity is greater in offshore environments, except during the mPWP when offshore communities also exhibited greater dissimilarity. The temporal turnover in composition decreased again with depth as global temperatures decreased after the mPWP. The structure of mPWP communities suggests that warming and sea-level rise contributed to the expansion of vegetated bottoms (onshore) and shelly and coralligenous bottoms (offshore). Although the effects of mPWP warming did not change the onshore–offshore gradient in the long term, its effect disproportionately affected deeper environments, in contrast to colder climate regimes.