Jarosław Tyszka

Response of middle Jurassic benthic foraminiferal morphogroups to dysoxic/anoxic conditions in the Pieniny Klippen Basin, Polish Carpathians

Abstract The distribution of foraminiferal morphological groups has been analyzed in Upper Aalenian-Lower Bajocian black siltstones and mudstones of the Pieniny Klippen Belt, Polish Carpathians. The deposits are assigned to middle neritic, outer and upper bathyal zones represented by three succession, and contain agglutinated and calcaeous foraminifera assemblages. Separate classifications of agglutinated and calcareous morphogroups are established and used for a palaeocological study. The groups are distinguished on the basis of morphological features, modes of life, and feeding habits as inferred from modern analogues. Infaunal preferences of some foraminifera have been supported by comparison with other infaunal indicators such as trace-fossil tiering and abundance of infaunal ostracods. A new quantitative method to estimate dissolution of calcareous tests has been tested on the most common genus Lenticulina . It reveals a special survival strategy of this genus in suboxic, muddy, and flocculent substrate. The distribution of morphogroups in comparison with other palaeoecological, taphonomical, and sedimentological indicators allows interpretations of organic input, rate of sedimentation, level of oxygenation, position of the redox boundary, and p H. The studied deposits represent regional anoxic/dysoxic event which occured within a semienclosed silled basin.

Morphospace of foraminiferal shells: results from the moving reference model

The moving reference model of foraminiferal tests (shells) is based on principal morphogenetic rules revealed from real foraminifera. The model has introduced apertures as moving reference points based on minimization of the distance between them. These modifications greatly enhanced variability of simulated shells closely resembling actual complexity of small polythalamous foraminifers. The resulted theoretical morphospace of all simulated forms is far more extensive than any produced before. The fragments of the multidimensional theoretical morphospace are presented in two forms, i.e. a (classical) box model and a morphotree . The theoretical morphospace of foraminifera reveals regions of the morphospace that include similar forms. These specific fields in the morphospace, called morphophases , are separated from each other by either sharp or gradual morphophase transitions , which involve sharp or gradual changes in morphology controlled by changes of the model parameters. Optimized emplacement of foraminiferal apertures is responsible for these morphophase transitions . The overall morphospace splits into the ‘possible range’ and the ‘forbidden range’. The ‘possible range’ includes existent and nonexistent foraminiferal forms, which are further separated into ‘vacant’, ‘dysfunctional’, and ‘deficient’ ranges. All the ranges provide additional knowledge on theoretical foraminiferal morphology. The ‘vacant range’ of possible, although nonexistent, morphologies is limited and that may suggest that the real evolution of foraminifera has discovered most of the morphologic possibilities. It is suggested that the ‘forbidden’ and ‘deficient’ ranges present model constraints useful for understanding morphogenesis, which may be tested by further modifications of the model. The analysed theoretical morphospace verifies the moving reference model, indicating the fundamental role of apertures in the morphogenesis of foraminifera. I Foraminiferida, modelling, morphogenesis, morphophase transition, theoretical

Paleoenvironmental implications from ichnological and microfaunal analyses of Bajocian spotty carbonates, Pieniny Klippen Belt, Polish Carpathians

The nature and distribution of trace-fossil and microbenthic assemblages in Tethyan hemipelagic carbonates and marks of the Podzamcze Formation (Bajocian, Pieniny Klippen Belt) are studied. These analyses allow the identification of (1) recurring Planolites-Chondrites, Planolites-Chondrites-Zoophycos/Teichichnus and Chondrites ichno-assemblages, and (2) poor microbenthic assemblages dominated by agglutinated foraminifers and rich microbenthic assemblages dominated by diversified calcareous foraminifers as well as ostracods. A cross correlation of trace-fossil and microbenthic assemblages with the lithology and petrography of their host sediments suggests the presence of three different paleo-oxygen levels ranging from strongly dysaerobic, moderately dysaerobic to slightly dysaerobic (or aerobic)

A new approach to modeling of foraminiferal shells

Abstract The emergence of shell forms in the growth of foraminifera is an essential problem in the morphogenesis of these microorganisms. We present a model of foraminiferal shells that applies a moving-reference system. Previous models have referred to fixed-reference axes and have neglected apertures. Our model focuses on real morphologic characteristics and follows stepwise natural biological processes. It introduces apertures based on minimization of the local communication path and applies three parameters, which are either predetermined or selected at random from given ranges. Expression of stochastic parameters mimics phenotypic variability of a shell. We also present a detailed description of the method with examples of simulated shells and the first step toward analyses of the theoretical morphospace. The morphospace is divided into certain regions (phases) separated by transitional planes (phase transitions). Further prospects for foraminiferal modeling, which should focus on more in-depth models based on realistic intracellular dynamics, are also presented.

A new vent−related foraminifer from the lower Toarcian black claystone of the Tatra Mountains, Poland

Recurvoides infernus sp. nov., one of the oldest representatives of the superfamily Recurvoidacea (Foraminifera), is described from a thin black claystone overlying the manganese deposits of the Krížna Unit in the Western Tatra Mountains (Poland). These manganese carbonates/silicates were laid down around a shallow-water exhalative submarine hydrothermal vent that was active in the early Toarcian. The microfossils are possibly the first described Jurassic foraminifera associated with hydrothermal vents. The assemblage is characterized by a high abundance and dominance of this new species. The primary lamination of the black claystone, the lack of any macrofauna, and an elevated TOC content point to oxygen-deficient conditions during sedimentation of these deposits. Furthermore, the nearly exclusive occurrence of agglutinated foraminifers suggests a low pH level. It is likely that the foraminifers colonized vent-related bacterial mats which acted as a rich and stable food source. Modern shallow- and deep-water hydrothermal vents may represent similar habitats.

Local Minimization Paradigm in Numerical Modeling of Foraminiferal Shells

We present a new approach to modelling of foraminiferal shells. Previous models referred to fixed reference axes and neglected apertures, which play a crucial role in morphogenesis of shells. Our 2D preliminary model applies the moving reference system based on introducing of apertures and minimization of the local communication path (LCP). LCP defines the position of every final aperture. A formal description of simple analytical methods with some elements of randomness is given in this paper. Selected examples of simulated shells are figured.

Spiroplectinata, key benthic foraminifer genus for palaeoceanographic reconstruction of the Albian Lower Saxony Basin

Abstract This paper is focused on Albian Spiroplectinata, a morphologically unique, benthic, agglutinated foraminifer genus, and its application for reconstructing changes in the water masses within the Lower Saxony Basin. A new interpretation of microhabitat preferences and feeding habit for Spiroplectinata is proposed and discussed. Their functional morphology, composition of their tests, and their relationships with adherent foraminifera suggest that at least adult individuals of Spiroplectinata were epibenthic and were either suspension or deposit feeders. The suspension-feeding mode is favoured because this genus is associated with adherent suspension-feeding foraminifera and it does not correlate with other epibenthic deposit feeders. Spiroplectinata constructed an elongated uniserial terminal part, which probably facilitated an erect position to spread a reticulopodium well above the sediment/water interface. The distribution of this foraminifer can, therefore, be used here as a sensitive indicator for the existence of bottom currents. Four (or five) periods of intensified bottom water circulation around the Early/Middle Albian boundary (S-1), Middle (S-2), late Middle to earliest Late Albian (S-3, probably represents two intervals) and early Late Albian (S-4) are reconstructed and well marked by maxima of Spiroplectinata annectens, S. complanata, and Spiroplectinata sp. A. S. annectens is known from strata in the Western Tethys (i.e. in the Late Aptian and Early Albian) that are older than those in the ‘Boreal’ realm. Its first appearance in the Lower Saxony Basin occurs in the late Early Albian, followed by the first maximum just above the Early/Middle Albian boundary, and probably represents the main immigration event into the Lower Saxony Basin. This supports the idea that the deep water in the late Early to early Late Albian ‘Boreal’ epicontinental sea during ‘the Spiroplectinata intervals’ came from the Tethys and not from the polar regions. If one interprets the plankton/benthos foraminifera ratio as reflecting sea-level changes, it implies that sea-level rises may have been responsible for opening and/or deepening of ‘Boreal’/Tethyan gateways that activated extensive exchange of water masses. This late Early Albian and early Late Albian ‘invasion’ of Tethyan water can be correlated with a general global warming, and shifting of climate zones.

A reassessment of ‘Globigerina bathoniana’ Pazdrowa, 1969 and the palaeoceanographic significance of Jurassic planktic foraminifera from southern Poland

‘Globigerina Ooze’, Foraminiferal Ooze or Carbonate Ooze as it is now known, is a widespread and highly characteristic sediment of the modern ocean system. Comparable sediments are much less common in the geological record although, as we describe here, a number of Middle Jurassic carbonate sediments with distinctive assemblages from Central Europe fulfil many of the criteria. One important component of these assemblages in the Middle Jurassic is ‘Globigerina bathoniana’ Pazdrowa, 1969, first described from the Bathonian sediments near Ogrodzieniec (Poland). The generic assignment of this species and other coeval Jurassic taxa is discussed. This species and many of the other early planktic foraminifera evolved in the Aragonite ll Ocean, together with the other two oceanic carbonate producers: the calcareous nannofossils and the calcareous dinoflagellates. The preservation of carbonate sediments with abundant planktic foraminifera on the sea floor indicates that, by the mid-Jurassic, the carbonate/aragonite compensation depths (and associated lysoclines) must have developed in the water column.

Modelling ecology and evolution of Foraminifera in the agent-oriented distributed platform

Abstract We present a new software platform called eVolutus for simulating evolution of living organisms. We choose Foraminifera as model organisms that represent a group of single-cellular, mainly marine, organisms that construct well fossilisable protective shells. They have lived on Earth for more than 540 million years and have left an extraordinary fossil record that is excellent for testing palaeoecological and evolutionary hypotheses. We use the AgE platform, which is a lightweight agent-oriented platform supporting distributed computation. The paper presents the general architecture of this modelling environment as well as more detailed descriptions of the implemented rules and applied solutions. The utility of this software is demonstrated by presenting the configuration and results of sample experiments.

eVolutus: A New Platform for Evolutionary Experiments

eVolutus is a new software platform designed for modeling evolutionary and population dynamics of living organisms. Single-celled eukaryotes, foraminifera, are selected as model organisms that have occupied the marine realm for at least 500 Ma and left an extraordinary fossil record preserved in microscopic shells. This makes them ideal objects for testing general evolutionary hypotheses based on studying multiscale genotypic, phenotypic, ecologic and macroevolutionary patterns. Our platform provides a highly configurable environment for conducting evolutionary experiments at various spatiotemporal scales.