Sieve-type pore canals in the Timiriaseviinae-A contribution to the comparative morphology and the systematics of the Limnocytheridae (Ostracoda, Crustacea)

Examination of normal pore canals, especially sieve-type pore canals, in living and fossil representatives of ten genera of the family Limnocytheridae, subfamily Timiriaseviinae, has revealed important diversity of structure. These complex pore canals have been studied via high-resolution scanning electron microscopy (the Cartographic Method) and analysed via the application of newly devised indices to assess patterns of consistency and variation in both detailed structure of individual pores and of their distribution on the calcified valve. The timiriaseviine taxa are compared with species of the genera Limnocythere, sub-family Limnocytherinae and Cyprideis (family Cytherideidae). The relationship between the living animal and its aquatic environment is discussed in the light of previous studies and of new evidence herein. The importance of normal pore canals for systematics is highlighted by the recognition and definition of the new tribe Gomphodellini Danielopol, Cabral Lord nov. tribe, subfamily Timiriaseviinae, family Limnocytheridae.

Evaluating the performance of water purification in a vegetated groundwater recharge basin maintained by short-term pulsed infiltration events

Infiltration of surface water constitutes an important pillar in artificial groundwater recharge. However, insufficient transformation of organic carbon and nutrients, as well as clogging of sediments often cause major problems. The attenuation efficiency of dissolved organic carbon (DOC), nutrients and pathogens versus the risk of bioclogging for intermittent recharge were studied in an infiltration basin covered with different kinds of macrovegetation. The quality and concentration of organic carbon, major nutrients, as well as bacterial biomass, activity and diversity in the surface water, the porewater, and the sediment matrix were monitored over one recharge period. Additionally, the numbers of viral particles and Escherichia coli were assessed. Our study showed a fast establishment of high microbial activity. DOC and nutrients have sustainably been reduced within 1.2 m of sediment passage. Numbers of E. coli, which were high in the topmost centimetres of sediment porewater, dropped below the detection limit. Reed cover was found to be advantageous over bushes and trees, since it supported higher microbial activities along with a good infiltration and purification performance. Short-term infiltration periods of several days followed by a break of similar time were found suitable for providing high recharge rates, and good water purification without the risk of bioclogging.

On the Evolutionary Biology of Elpidium Ostracods (Limnocytheridae, Timiriaseviinae): A Proposal for Pluridisciplinary Studies

The present essay reviews the history of the research on Elpidium ostracods (Timiriaseviinae), a group exclusively known to live in micro-aquaria of phytotelmata from Neotropical bromeliaceans. A new species, E. martensi n. sp., is described and aspects dealing with functional morphology and taxonomy of the genus are presented. Related to these topics an evolutionary hypothesis and a programme of pluridisciplinary research are proposed. This should allow further improvement of our knowledge on the origin and evolution of the subfamily Timiriaseviinae, one of the most diverse cytheroid ostracod groups in inland waters since the beginning of the Mesozoic. Specifically, the following aspects are treated in-depth in the essay: (1) morphologic traits of the valves, useful for characterisation of Timiriaseviinae taxa; (2) the reversal of the valve overlap and hinge elements; (3) the diverse development of the posterior half of the female carapace, a quasi-independent morphological trait; (4) the morphological shapes of the male copulatory process; (5) the functional significance of the antero-ventral segment of the valve selvage for the life of Elpidium ostracods in the micro-aquaria of the bromeliaceans; (6) the necessary improvement of comparative descriptions of the limbs-chaetotaxy for Timiriaseviinae.

Redefinition of the Genus Typhlocypris Vejdovský, 1882 (Ostracoda, Candonidae)

The taxonomy of the genus Typhlocypris Vejdovský, 1882 is reviewed. New morphological information on Typhlocypris eremita (Vejdovský, 1882), the type species of the genus, is provided, and a new reference material is presented. The generic diagnosis is emended with details derived from the developmental trajectory of the valves, from the juvenile stage A-3 to the adult. Those criteria clearly differentiate Typhlocypris from the related genus Pseudocandona Kaufmann, 1900. As here redefined, Typhlocypris is a phylogentic lineage of the subfamily Candoninae containing extant species presently living in aquatic subterranean habitats and fossil species recovered from non-marine Late Palaeogene to Neogene and Quaternary deposits in Europe and western Asia. The type species of Typhlocypris is considered a metaspecies, taxonomically treated as T. eremita (sensu lato), which includes populations resembling the newly designated reference material. The homeomorphic triangular valve shape of the Candoninae is discussed. Careful examination of the valve morphology of Typhlocypris combined with the analysis of limb traits helps to distinguish representatives of this genus from unrelated phylogenetic groups presenting similar triangularly shaped valves. It is emphasised that for a useful description of Typhlocypris taxa both transmitted light and scanning electron microscopy are necessary.

On the Leptocytheridae Ostracods of the Long-Lived Lake Ohrid: A Reappraisal of their Taxonomic Assignment and Biogeographic Origin

Leptocythere karamani Klie, one of few non-marine species of the family Leptocytheridae (Ostracoda), is redescribed from specimens recently collected from the long-lived Lake Ohrid on the Albanian-Macedonian border. Detailed morphologies of valves and limbs of this species were compared with those of other Ohrid-Prespa leptocytherids, of some recent marine representatives of the genera Leptocythere Sars and Callistocythere Ruggieri from the Mediterranean, Irish and Baltic seas as well as with that of fossil non-marine species from the Miocene palaeo-Lake Pannon belonging to the genera Amnicythere Devoto and Euxinocythere Stancheva. Comparison with other species of Leptocytheridae inhabiting fresh to brackish waters of the Black-Azov, Caspian and Aral seas were also carried out using descriptions provided in the literature. Based on the comparative morphological studies it is shown that L. karamani and other Ohrid leptocytherids have a number of characters distinguishing them from other members of the genus Leptocythere but demonstrating a relationship with species of the genus Amnicythere. The most reliable of these characters are: a) anterior valve vestibulum from where mostly uni-ramified pore canals start, b) the entomodont hinge type with a strong anterior anti-slip tooth, a smooth posterior anti-slip bar on the left valve, and c) the hemipenis with underdeveloped lateral lobe and reduced clasping organ. From this strong evidence, the Ohrid leptocytherid species are allocated to the genus Amnicythere. Finally, a biogeographic scenario on the origin of the Ohrid leptocytherids is proposed which matches the "Lake Pannon derivate hypothesis". Close relationship of the Ohrid Amnicythere species with the non-marine leptocytherid taxa from the Neogene lakes of Central and Eastern Europe and with extant taxa from the Black and Caspian seas may indicate that the Ohrid Amnicythere derived from Lake Pannon species which were able to colonise lakes in Southern Europe through a stepping-stone process and subsequently to adapt to freshwater environment.

How and why to achieve greater objectivity in taxonomy, exemplified by a fossil ostracod (Amplocypris abscissa) from the Miocene Lake Pannon

A project on fossil ostracods from Hennersdorf (Vienna Basin, Middle Pannonian "E" stage) documents the non-marine ostracod Amplocypris abscissa (Reuss 1850) as a polymorphic taxon. The high morphological variability of the valves belonging to this species and its geographic distribution in the Lake Pannon point to a widely spread fossil taxon. This traditional view emerges from the fact that A. abscissa displays few homologous "landmarks" (morphological reference points) which makes it difficult to compare morphotypes within and among populations. The present contribution offers arguments for the need of objective criteria when describing ostracods with few visible morphological traits. It is demonstrated that using a composite algorithmic approach which combines information implemented in the computer programme MORPHOMATICA for different variables, measured on interval and ratio scales, is able to define morphological traits objectively. The data analysed with multivariate statistics are further used for diagnostic profiles of clearly delineated morphotypes. The potential taxonomic value of three morphotypes here identified for Amplocypris abscissa is discussed. It is argued that this taxon represents a phylogenetic lineage within which a cluster of species with discrete morphological traits exists. Finally, it is proposed to apply similar algorithms for the necessary revision of the whole group of Amplocypris species from Lake Pannon.

Centennial- to decadal scale environmental shifts in and around Lake Pannon (Vienna Basin) related to a major Late Miocene lake level rise

A detailed ultra-high-resolution analysis of a 37-cm-long core of Upper Miocene lake sediments of the long-lived Lake Pannon has been performed. Despite a general stable climate at c. 11-9 Ma, several high-frequency oscillations of the paleoenvironments and depositional environments are revealed by the analysis over a short time span of less than 1000 years. Shifts of the lake level, associated with one major 3rd order flooding are reflected by all organisms by a cascade of environmental changes on a decadal scale. Within a few decades, the pollen record documents shifting vegetation zones due to the landward migration of the coast; the dinoflagellate assemblages switch towards "offshore-type" due to the increasing distance to the shore; the benthos is affected by low oxygen conditions due to the deepening. This general trend is interrupted by smaller scale cycles, which lack this tight interconnection. Especially, the pollen data document a clear cyclicity that is expressed by iterative low pollen concentration events. These "negative" cycles are partly reflected by dinoflagellate blooms suggesting a common trigger-mechanism and a connection between terrestrial environments and surface waters of Lake Pannon. The benthic fauna of the core, however, does not reflect these surface water cycles. This forcing mechanism is not understood yet but periodic climatic fluctuations are favoured as hypothesis instead of further lake level changes. Short phases of low precipitation, reducing pollen production and suppressing effective transport by local streams, might be a plausible mechanism. This study is the first hint towards solar activity related high-frequency climate changes during the Vallesian (Late Miocene) around Lake Pannon and should encourage further ultra-high-resolution analyses in the area.

The Chaetotaxy of Cypridacea (Crustacea, Ostrocoda) Limbs: Proposals for a Descriptive Model

The need for better and more systematic descriptions of the chaetotaxy (especially data concerning the shape, structure and pattern of distribution of the setae) is emphasized. The historical developments of studies in chaetotaxy are reviewed.

An Essay to Assess the Age of the Freshwater Interstitial Ostracods of Europe

The freshwater ostracods living exclusively in interstitial and/or interstitial and cavernous habitats belong to the Candoninae, Pseudolimnocytherinae, Timiriaseviinae, Kliellinae and Darwinulidae. An assessment of the antiquity of several interstitial ostracod groups has been attempted using direct evidence from the phylogenetical affinities between living hypogean and fossil ostracod species, and indirect evidence from the morphological characters of the subterranean ostracods and from the bio- and paleobiogeographical distribution of the different ostracod groups.