This work describes the primary type collection (holotypes, lectotypes, neotypes, and syntypes) of foraminifera at the Natural History Museum Vienna. The collection dates back to the material of Fichtel and Moll from the 18th century and covers the geographic area of the former Habsburg Empire as well as some special locations outside of the Empire (e.g., New Zealand and the Philippines).A historic context of the collection is provided, as well as a chronological discussion of the type material for each author from 1798 to 2018. A statistical analysis of the metadata associated with more than 500 type species, including stratigraphic age, area of origin, and date of description emphasizes the diversity and scientific spectrum of the collection.With this combined approach, the significance of the Vienna type collection as one of the most important repositories for foraminiferal taxonomy is highlighted, which has a history of more than 200 years.

This paper addresses the long-standing taxonomic issue of the supra-species classification of Mesozoic taxa with an agglutinated wall originally included in the genus Tetrataxis, the type species of which, Tetrataxis conica, ranges into the Palaeozoic and has a different wall texture. Our investigation is based on the re-examination of the types of Mesozoic species assigned to Tetrataxis, and to the co-occurring genus Duotaxis. Moreover, we document their morphological variability and occurrences in different lithofacies types of two Tethyan carbonate platform sections, Mt Messapion (Pelagonian Platform, Greece) and Valle Agricola (Apennine Platform, Italy), encompassing the interval of the end-Triassic extinction (ETE). Our taxonomic investigation supports the validity of the genus Duotaxis and the necessity to erect a new genus named Kristanita to accommodate Mesozoic species incorrectly assigned to Tetrataxis. Duotaxis and Kristanita represent the only known genera of the family Duotaxidae (Class Spirillinata). This group possesses a well-developed umbilical cavity, a keeled periphery and supplementary structures on the umbilical side. Our study suggests that the Duotaxidae lived clinging or attached to rock or biogenic substrates in carbonate platform environments characterized by water turbulence and tolerated a high nutrient supply and sharp environmental changes. Both genera survived the ETE and were among the first colonizers of carbonate platforms long after the biotic crisis (Lazarus taxa). The eurytopic ecology and resilience to one of the big five extinctions in Earth's history may explain the long evolutionary history of Spirillinata and highlight their important role in the post-crisis recovery of benthic ecosystems.

This study reports on a rare assemblage of deep-marine elasmobranchs from the middle Badenian (Langhian) of Austria, which has been recovered by extensive bulk sampling of sediment deposited in the Krems embayment. The applied multidisciplinary approach enabled an age assignment, placing the assemblage around the mid Badenian flooding event (14.59 +/- 0.2 Ma). Palaeoenvironmental reconstruction, based on a well-preserved foraminifera assemblage and fish otoliths, indicates predominantly oxic to suboxic with partially dysoxic conditions of a rather deep-marine (>100 m) setting, which align with the recovered elasmobranch taxa. Despite analyzing 180 kilograms of sediment, only five elasmobranch teeth were recovered. The low number of teeth and the extraordinarily well-preserved foraminifera argue for an autochthonous deposition and point to high sedimentation rates associated with the flooding event. The teeth represent five different elasmobranch orders (Squaliformes, Squatiniformes, Carcharhiniformes, Torpediniformes, and Myliobatiformes) with a wide range of feeding behaviors, providing new insights into the ecological structure of this deep-marine environment. Despite common genera known from other marine settings of the Paratethyan realm (e.g., Squatina, Scyliorhinus, and Centrophorus), this study documents the first distinct records of Torpedo and Mobula from Austria, expanding the known palaeogeographic distribution of these taxa.

The ecological upheavals produced by the Cretaceous-Paleogene mass extinction event (K-Pg, -66 Ma) have been mostly studied at large scale with emphasis on clades' diversity dynamics. How this event affected the structure of paleocommunities is comparatively less investigated, especially within large vertebrate clades like fish. Here, we quantified changes in the contribution of elasmobranchs (sharks, skates, rays) and actinopterygians (ray-finned fishes) to the fish community across the K-Pg extinction by analyzing ichthyolith (fossil teeth and denticles) abundance through time. Based on extensive sampling of 20 horizons from two outcrops spanning the K-Pg event in Austria (>4 tons of rock, >9,000 ichthyoliths), we show that the K-Pg event fostered elasmobranch abundance while reducing actinopterygian density in the Tethys Ocean. Elasmobranch ichthyolith dominance in postextinction communities is not driven by estimated local environmental change (paleobathymetry, bottom-water oxygenation) and may relate to the greater independence of this clade from lower trophic levels in their ecology and early life stages than actinopterygians. We further measured the size structure of ichthyolith assemblages and found that the K-Pg event initiated an increase in the range of ecological niche space occupied by elasmobranchs simultaneously to the demise of actinopterygians in postextinction communities. Finally, using the fine taxonomic resolution of the elasmobranch fossil record, we demonstrate that local environmental fluctuations controlled elasmobranch community structure and richness, which are decoupled from global-scale upheavals. Our results challenge previous hypotheses and provide insights into global and regional environmental forcing over the structure of fish communities across a mass extinction event.

Corfu Island (Greece) is located in the northern Ionian Sea and exhibits unique and diverse marine coastal habitats suitable for high-diversity assemblages such as shallow-water foraminifera. The island also lies near the current range expansion front of the invasive species Amphistegina lobifera. We analyzed the foraminiferal assemblages of 51 samples from 25 sites around the island, calculated diversity indices, and analyzed the community structures of foraminiferal assemblages in comparison to local environmental variables. In addition to that, using the spatial structure or relative abundances, we evaluated the effect of A. lobifera on the species richness of all benthic foraminifera and habitat-specific groups. With 200 benthic foraminiferal species found, the high species richness and other diversity indices indicate Corfu as an area of high diversity. The main ecological drivers for the assemblage compositions were water depth, sediment texture, and habitat (especially vegetation), resulting in three main assemblage clusters around the island: (1) sandy or rocky, shallow-water areas from the south and west; (2) deeper areas from the west; and (3) rocky, vegetated areas of variable depths from the northwest and northeastern parts of the island. Our analyses suggest that the invasive species A. lobifera affects local diversity of the foraminiferal assemblage and that these effects become apparent when the invasive species accounts for more than 10%-20% of the total abundance. We also observed significant negative correlations with sessile epiphytes and smaller miliolids. Both groups share similar microhabitats with A. lobifera and might be outcompeted, which is probably further facilitated by ongoing ocean warming. However, other warm-affiliated taxa (e.g., other symbiont-bearing species) initially show a positive correlation with the increasing presence of A. lobifera until the latter exceeds 20%. We expect that A. lobifera and other warm-adapted species will play an increasing role in shaping future biodiversity and assemblage composition in this area, a feature that supports the prognosed tropicalization of the Mediterranean Sea.

We present a journey through the history of the Austrian Arctic collections stored in Geological-Paleontological Department of the Natural History Museum Vienna (NHMW). The NHMW-material was mainly acquired during four expeditions. The first was an Isbjørn expedition designed as a test cruise by Julius Payer and Carl Weyprecht in 1871. One year later, there was a second Isbjørn expedition under the command of Count Johann Wilczek. In 1873, Richard von Drasche, an industrial magnate with geological expertise, organized a private trip to eastern Spitzbergen (Svalbard). The fourth one was from 1872 to 1874, when Payer and Weyprecht led the Austro-Hungarian North Pole Expedition on the ship Admiral Tegetthoff. The latter, which almost ended in a catastrophe, discovered Franz-Josef-Land. After these expeditions, Austria took part in the First International Polar Year (1882–1883), with its own research station at Jan Mayen. There are numerous types provided by these expeditions that make this collection and its archival material an important source for the geological history of the Arctic region.

Shallow-water banks of foraminiferal propagules (tiny juveniles <63 µm) harbor a hidden assemblage composition that has altered our understanding of traditional distribution patterns. Propagules can be transported well beyond their environmental limits and remain dormant until local conditions become suitable. Therefore, the composition of propagule assemblages is expected to differ from “adult” assemblages. This offers various opportunities for a better understanding of foraminiferal reactions to environmental changes and also of the variability of living foraminiferal populations throughout the year. To date, propagule assemblages have only been analyzed “passively” through growth experiments with propagule banks under laboratory conditions. Here, we apply for the first time a combination of a multi-week cultivation experiment and eDNA metabarcoding of the different size fractions. Sediment samples were taken from a shallow lagoon in Corfu (Greece) and sieved over 63 µm to separate the propagule bank from the coarser fraction. The in-situ material of the sampling site was used as a baseline for the subsequent experiment (T0). The finer fraction (<63 µm) was set up in a culture experiment for 15 weeks under stable conditions (22°C, 38 psu, constant aeration). The cultures were repeatedly harvested for grown foraminifera (>63 µm) every 5 weeks (T1–T3). At the same intervals, samples were taken and re-sieved over 63 µm for eDNA metabarcoding of both size fractions. The morphology-based count data of the foraminiferal specimens revealed significantly different assemblage compositions after each harvest (T0–T3). The differences between the in-situ (T0) and the experimental samples (T1–T3) were most distinct, indicating a specific composition of the propagule bank. The differences between in-situ and experimental assemblages as well as the shifting assemblage compositions over time were mirrored by the metabarcoding data from the respective intervals. Our results highlight the potential for metabarcoding to complement and expand insights gained from morphology-based approaches in foraminiferal studies.

Jullienella foetida is probably the largest agglutinated foraminifer in modern oceans and can reach a length of up to ~14 cm. Because of its large size, the species was initially considered to be a bryozoan, but later correctly described as a single-chambered (monothalamous) foraminifer with a large, flat or slightly undulating plate-like test, leaf-like, or fan-like in overall shape and with the chamber interior subdivided by longitudinal partitions. It occupies a restricted geographical range around part of the NW African margin where it is found in eutrophic settings with a preference for energetic environments. We have applied a suite of non-destructive methods, namely light microscopy, SEM, X-ray and high-resolution micro-computed tomography (micro-CT) to 1) explore its external and internal test characteristics and 2) to provide a first-order estimate of its possible contribution to sea floor biomass. High-resolution SEM images show the test wall to comprises a smooth, outer veneer of small mineral grains that overlies the much thicker inner layer, which has a porous structure and is composed of grains measuring several hundreds of microns in size. X-ray images of the test reveal an elaborate system of radial partitions that subdivides the test interior into channels that may serve to direct the flow of the cytoplasm, and perhaps increase its surface to volume ratio. Micro-CT scans suggest that much of the test interior is filled with cytoplasm with a biomass comparable to that of slightly larger xenophyophores. This remarkable species appears to play an important, perhaps keystone, role in benthic ecosystems where it is abundant, providing the only common hard substrate on which sessile organisms can settle.

We present new observations on Jullienella foetida Schlumberger, 1890, a giant agglutinated foraminifer with a leaf- or fan-like test reaching a maximum dimension of 14 cm, that is common on some parts of the west African continental shelf. The test wall comprises a smooth, outer veneer of small (<10 µm) mineral grains that overlies the much thicker inner layer, which has a porous structure and is composed of grains measuring several hundreds of microns in size. Micro-CT scans suggest that much of the test interior is filled with cytoplasm, while X-ray micrographs reveal an elaborate system of radiating internal partitions that probably serve to channel cytoplasmic flow and strengthen the test. Jullienella foetida resembles some xenophyophores (giant deep-sea foraminifera) in terms of test size and morphology, but lacks their distinctive internal organization; the similarities are therefore likely to be convergent. Based on micro-CT scan data, we calculated an individual cytoplasmic biomass of 3.65 mg wet weight for one specimen. When combined with literature records of seafloor coverage, this yielded an estimate of >7.0 g wet weight m −2 for the seafloor biomass of J. foetida in areas where it is particularly abundant. The relatively restricted distribution of this species off the north-west African coast at depths above 100 m is probably related to the elevated, upwelling-related surface productivity along this margin, which provides enough food to sustain this high biomass. This remarkable species appears to play an important, perhaps keystone, role in benthic ecosystems where it is abundant, providing the only common hard substrate on which sessile organisms can settle.

Benthic foraminifera are important indicators for ecological studies. The assemblage composition of local communities can be used to analyze influences of environmental variables such as temperature, salinity, pH, and others. In recent years, the experimental propagule method has emerged as an effective tool to evaluate the influence of these variables on assemblage dynamics of benthic foraminifera. Propagules (tiny juveniles) of benthic foraminifera are widespread and can survive outside of a species’ natural distribution range. Their ability to become dormant and be re-activated once local conditions become suitable, is an important driver behind the capacity of foraminiferal assemblages to react quickly to environmental changes. In the laboratory, the propagules are first separated from the coarser fractions by sieving and then cultured under different conditions. In the present study, we analyzed the effect of ocean pH on the composition of shallow-water assemblages from Corfu Island (Greece). Like other calcifying organisms, assemblages of foraminifera are susceptible to pH variations and have revealed compositional shifts along natural or experimental pH gradients. Our experimental set-up included four pH treatments between 6.5 and 8.5 at constant temperature and salinity (22°C and 38 ppt) for 5 weeks. At the conclusion of the cultivation experiment, we found high numbers of grown specimens (825–1564 per replicate) and a high survivability rate throughout all treatments (78–87%). Higher pH (7.8 and 8.5) resulted in assemblages that were dominated by monothalamous and porcelaneous species, whereas lower pH (6.5 and 7.2) lead to a reduction in porcelaneous and an increase in agglutinated species. Several taxa showed significant positive or negative correlations with decreasing pH values. Our results are congruent with previous findings that reported compositional shifts from calcareous to agglutinated taxa with decreasing pH (both from culture and field observations). Our study also indicates that the activation of propagules is an important mechanism behind assemblage dynamics in shallow-water foraminifera. As such, it offers an improved insight into potential resilience and recovery mechanisms of foraminiferal assemblages with regard to local or seasonal pH variations as well as ongoing ocean acidification.

Calcifying organisms such as benthic foraminifera are susceptible to changes in ocean pH and alkalinity. Responses to these changes include variations in mortality, calcification rates or assemblage composition, which have been observed in field and experimental studies. Here we applied a growth experiment with benthic foraminiferal propagules under different pH conditions to gather insights into the effect of pH on the composition of grown assemblages. A homogeneous propagule assemblage from a local mudflat in Corfu Island (Greece) was exposed to a range of pH conditions (6.5, 7.2, 7.8 and 8.5) for 5 weeks. In a second experiment, the assemblages were first exposed to low and subsequently to high conditions for a total of 8 weeks. After termination of the experiments, we recorded high survivability and growth throughout the treatments. Analysis of the assemblage composition of the first experiments revealed a shift from porcelaneous dominated taxa in the higher pH treatments to an assemblage with higher numbers of agglutinated taxa in the lower pH treatments. Soft-shelled monothalamous species were common throughout. The second experiment revealed assemblages that were significantly dominated by porcelaneous taxa with monothalamous taxa being almost absent. The results of this study are congruent with other observations on changing assemblage compositions with changing pH from both laboratory and field studies. The fast response of the assemblages through activation of potentially dormant propagules adds insights into the mechanisms behind seasonal composition changes in naturally variable environments such as river estuaries. They also shed new light on possible effects of continuous decreases in ocean pH on shallow-water foraminiferal assemblages in future.

Foraminiferal propagule banks occur in fine sediment fractions that contain small individuals of benthic foraminifera. These sediments include locally sourced juveniles and propagules, as well as allochthonous propagules that have dispersed from surrounding areas. Such propagules can remain viable even under unfavorable local conditions. When exposed to more favorable conditions, they may grow to adult stages. Accordingly, during environmental changes, propagule banks have the potential to function as species pools and allow quick assemblage reactions. The propagule method was designed to study responses of foraminiferal assemblages by exposing propagule banks to controlled conditions in the laboratory, an approach that is applicable to a variety of ecological questions. Therefore it is important to understand the nature and dynamics of propagule banks, including local and seasonal influences. To obtain insights into the composition of local propagule banks, we studied experimentally grown assemblages from two shallow-water lagoons on Corfu Island in western Greece, and compared the results with in situ assemblages. We sampled in spring and autumn of 2017 and experimental treatments included the use of different substrates in our experiments to account for potential effects on assemblage compositions. Results revealed that sediments from each lagoon contained a distinct propagule bank. We found abundant allochthonous taxa among specimens grown in all experimental treatments, indicating dispersal of propagules, and possibly also juveniles, from adjacent regions into both lagoons. The time of sampling had a significant effect on experimental assemblages, indicating that the composition of propagule banks can vary throughout the year. However, no significant differences were found in assemblages grown in different substrata, suggesting a stronger influence of water variables (e.g., temperature or salinity) on assemblage compositions. Moreover, the experimental set-ups favored small, fast-growing, sediment-dwelling species tolerant of relatively high organic content. Our findings highlight the potential of propagule banks as species pools and will help to refine and improve future applications of the method.

This study updates the current distribution, range expansion and establishment status of the non-indigenous species Amphistegina lobifera Larsen, 1976 and other foraminifera that are cryptogenic in the Sicily Channel. Prior to this study, amphisteginids were reported from the Levantine Basin, the Central Mediterranean (Tunisia, Malta, Pelagian islands) and the southern Adriatic Sea. Here, we provide new records documenting a north-western expansion in the Central Mediterranean. In summer-autumn 2017 and spring-summer 2018, we collected algae and sediment samples from shallow coastal habitats along the shores of the Maltese archipelago, southern and north-western Sicily, Pantelleria and the Aegadian islands. Analysis of the foraminiferal assemblages showed that A. lobifera is effectively established around Malta and in southern/south-eastern Sicily, and has reached the oceanographic boundary between the Central and Western Mediterranean. Our results also show that the thermotolerant A. lobifera is at an advanced stage of invasion in the Sicily Channel, probably favoured by a recent rise in Mediterranean sea surface temperatures. New species distribution models are provided for the years 2040-2050 and 2090-2100, indicating that the predicted warming trend will facilitate north-westward migration of Mediterranean amphisteginids along the coast of northern Africa into the Alboran Sea, and deep into the Adriatic Sea.

Transport of foraminiferal propagules is an important mode of dispersal in benthic foraminifera. Known to occur from tidal marshes and estuaries to deep-water environments, the former are particularly vulnerable to ongoing climate change. Because rising sea levels can have profound implications on local salinity and associated faunal compositions, transport of foraminiferal propagules within these environments can be crucial for local assemblages to respond to changing conditions. Here we focus on a shallow-water environment in southeastern Georgia to evaluate whether propagule transport occurs evenly or whether it shows a predominant direction, such as land- or seaward. Two sites were sampled in the Doboy Sound area: the southern tip of Sapelo Island and a site on the North River located approximately 10 km inland. We applied the propagule method using the fine fraction of the sediments that contains the propagule bank. Experimental conditions in the laboratory included three temperatures (18, 24 and 30 degrees C) and three salinities (15, 25 and 35) to simulate a range of environments that might trigger the growth of various foraminiferal species. While adult in situ assemblages of both sites were at least partly influenced by the adjacent salt marshes, experimentally grown assemblages were dominated by mudflat, estuarine or more open marine species. Thus, propagule transport from the more terrestrial side of the assemblage gradient is limited, while propagules of more marine species can be transported far into the extensive estuarine system of the study area, where they can remain viable within the local propagule banks. Results provide important insights into possible changes in foraminiferal assemblages with rising sea-level on the Georgia coast.

Tropical tide and rock pools are extreme environments with regard to temperature. They undergo diurnal heating and constitute natural laboratories to assess the fate of marine calcifiers under scenarios of global change. This study focuses on benthic foraminiferal assemblages from tide and rock pool sites from eastern Africa as “natural” laboratories to document the diverse spectrum of foraminiferal biotas potentially capable to succeed under conditions of future global warming. To date, the majority of foraminiferal thermal tolerance data have been compiled from laboratory experiments, anthropogenically heat-polluted or extreme hydrothermal vent areas. A total of 111 species of benthic foraminifera were recorded within the tide pool samples. Perforate species were most abundant (up to 84%), followed by porcellaneous taxa (up to 45%), while agglutinated species were only rare (up to 5%). Larger benthic foraminifera represented between 30 and 75% of the total assemblages with 8 observed genera. Species richness varied between 23 and 63 species per sample. The foraminiferal communities of most sites were dominated by larger perforate taxa such as Neorotalia calcar and Amphistegina spp., followed by a variety of small miliolid taxa (54 species) and small rotaliids (27 species). The surprisingly high foraminiferal species richness suggests that a large range of shallow-water benthic taxa appear to be capable to tolerate exposure to diurnally occurring temperature extremes (35°–>40°C). The large spectrum of benthic taxa recorded provides insight into potential acclimatization capacities of foraminiferal assemblages with regard to ongoing ocean warming and projected temperature changes. We infer that calcification in heat-tolerant benthic foraminifera, a group of productive carbonate producers, is more widespread than previously thought and will continue in future decades when water temperatures are significantly elevated. Tolerance to thermal stress is imperative for intertidal foraminifera and assemblages from tropical rock and tide pools appear to be less susceptible to future change. This capacity is central to the resilience to rising ocean temperatures and dictates how warming affects these delicate environments. Intertidal foraminiferal assemblages could potentially act as source populations for restocking and to mitigate detrimental effects of global change.

Environmental changes such as ocean warming or sea-level rise have a profound impact on shallow-water coastal environments. Benthic foraminifera have long been successfully used as indicators for ecologic responses. The propagule method is a useful tool to evaluate the reactions of entire assemblages of foraminifera when exposed to different environmental conditions. Here we present results from growth experiments of foraminiferal assemblages from three sites in coastal Georgia and Florida (USA) under different temperatures (18, 24 and 30 degrees C) and salinities (15 and 35). Results show that assemblages grown at the higher temperatures had greater abundances of foraminifera, whereas salinity was the primary factor in shaping the composition of the experimentally grown assemblages from the three sites. We also show that experimentally grown assemblages contain high numbers of exotic' species that result from successful propagule recruitment from outside of the original environments (e.g. the open shelf). Overall, opportunistic and previously termed pioneer species' proved to be the most successful constituents of the experimental assemblages, showing that reactions of foraminiferal assemblages to environmental changes can appear remarkably quickly (e.g. in the course of several weeks). Our observations on the faunal reactions to different temperatures and salinities indicate that ongoing environmental alterations of coastal areas will likely result in significant changes in the shallow-water foraminiferal assemblages of the coasts of Georgia and Florida. As such, our study provides general insights into the ecologic effects of current climate change.