Thesis (PhD)--Macquarie University, Division of Environmental & Life Sciences, Dept. of Biological Sciences, 2004. / Bibliography: p. 599-618 (pt. 1). / Introduction -- Materials and methods -- Taxonomic studies -- Species descriptions and keys to genera and species -- Tardigrades from cryptograms and leaf litter on soil and from a sand island -- The distribution of terrestrial tardigrades in eastern Australia. / The terrestrial tardigrade fauna of Australia has been given scant attention in the past. This study was undertaken to collect and identify terrestrial tardigrade species from a wide a variety of habitats in Australia. This new taxonomic data set was then used to explore zoogeographic patterns and processes in eastern Australia. -- The first part of this study is concerned with the clarification of some taxonomic problems which arose during the course of the study, the solution of which was essential in order to delineate species boundaries. In the family Macrobiotidae, two genera, Minibiotus and Calcarobiotus, are remarkable for the high number of species recorded in Australia relative to other parts of the world. Within the genus Macrobiotus many new species within two groups, hufelandi and harmsworthi, are described and it is concluded that the nominal species in each case is not part of the Australian fauna. A new genus, Haptobiotus, is described in the family Macrobiotidae. -- In order to clarify species within the Diphascon (D.) pingue group, populations were subjected to multivariate analysis. The analysis resulted in the conclusion that only two species in that group, D. pingue and D. pinguiforme, have so far been found in Australia. The study also resulted in the synonymisation with D. pingue and D. pinguiforme of two previously described species from Australia. -- The discovery of a new genus, Milnesioides, provides an insight into the structure and function of the buccal apparatus of the rare monotypic genus Limmenius within the family Milnesiidae. A new genus. Lexia, is described in the subfamily Itaquasconinae along with other members of this group which has been under-recorded in Australia. The descriptions of three species in the genus Antechiniscus provides new morphological detail for this genus and provides additional evidence that the genus is found only in cool temperate regions in the southern hemisphere. -- The 161 species in 34 genera found in this study are described and line drawings provided. Of the 161 species, 59 are new to science and a further 16 have been published as new species during the course of the project. Also included are descriptions of an additional 21 species, recorded from Australia by other authors but not found in this study. Eleven of these species are probably misidentified. Keys to genera and species are supplied. -- A small but revealing study provides some preliminary data on tardigrade species associated with cryptogams or leaf litter on soil and sand. The detection of a rich fauna suggests that such habitats need to be examined if the full tardigrade fauna of Australia is to be documented. -- Data from 36 sites in eastern Australia containing 141 species were subjected to multivariate analysis in order to elucidate zoogeographic patterns of tardigrade communities. The study, although preliminary in many ways, showed a high correlation between tardigrade communities and core zoogeographic subregions in eastern Australia, e.g., a northern monsoonal, a nontropical south-eastern and a dry central-western subregion. Two distinct habitat types within the south-eastern subregion, cool temperate rainforest and limestone sites also support distinct species communities. Each tardigrade community consists of cosmopolitan, pantropical, oriental, southern hemisphere and Australian species. The degree to which each of these types contribute to each community is discussed in terms of the evolutionary history and the climatic regime (primarily temperature and length of dry periods) of each subregion and, to a limited extent by passive dispersal. / Mode of access: World Wide Web. / 2 parts (xxvi, 618 leaves (pt. 1), 182 leaves (pt. 2) ill

I conducted a series of research programmes on various aspects of Tardigrada biology. The published results of which are hereby presented as part fulfilment of my submission for a PhD by publications at Plymouth University. In this thesis my research publications are grouped into four chapters: Ecology & Faunistics, Alpha Taxonomy, Freshwater Fauna – a taxonomic challenge, and Superfamilies. In the first, I highlight my early papers which dealt with the faunistic surveys as I trained in systematics and taxonomy of the phylum. Amongst the key findings reported were the protozoan symphoriant, Pyxidium tardigradum van der Land, 1966, Marley and Wright (1994); a new addition to the reported fauna of the United Kingdom, Greaves & Marley(1996); and my first work on international samples from Arctic Canada, Sutcliffe et al.(2000). In the second chapter, Alpha Taxonomy, I have included five papers. The first, Marley and Wright (1996), illustrates my work with one of the Royal Museums of Scotland’s collections, where I updated the diagnoses of their specimens and described a new addition to the Icelandic fauna. The second paper, Russell, Marley & Hockings (2001), demonstrates how I was searching for new research methods to apply to tardigrades. It was because of similar exploration, with methods of SEM preparation, that I was invited to join the Australian-Anglo team working on sediment core samples from Antarctic freshwater lakes, Gibson et al. 2009. The remaining two papers in the chapter describe species new to science, Echiniscus ollantaytamboensis Nickel, Miller and Marley, 2001, and my first sole authored paper describing a species new to science, Platicrista ramsayi Marley, 2006. The third chapter, Freshwater Fauna – a taxonomic challenge, deals with a programme of research based initially on my findings at the Royal Museums of Scotland, Edinburgh. This then required subsequent visits the USA and Italy to work on the taxonomic issues with original authors on their more recently described genera. I prepared the original Case for the ICZN, but this was then held by the commission for several years pending their amendments to the Code. I then rewrote the Case into the final paper, Marley, Bertolani & Nelson (2008). The final chapter consists of two papers in which I worked on combining my expertise on the morphological characters of the buccal apparatus and claws, and combining this with new molecular dataset derived from sequencing individual specimens. My colleagues on these papers were Dr S.J. McInnes and Mr C.J. Sands, both from the British Antarctic Survey. Overall I am including 14 published papers and 5 published conference abstracts and three online articles. The following taxa were erected during this work: Pseudobiotus kathmanae, Echiniscus ollantaytamboensis, Platicrista ramsayi, Ramazzottidae, Isohypsibiidae, Macrobiotoidea, Eohypsibioidea, Hypsibioidea, and Isohypsibioidea. Plus the following taxa were re-described, Pseudobiotus, Thulinius, Thulinius augusti, Thulinius ruffoi, and Thulinius stephanae.

Tardigrades are small water-dwelling invertebrates that can live almost anywhere in the world. Even though they are well-known our knowledge about them is still scarce. The aim of this study was therefore to explore our current knowledge about tardigrades by: (1) explore their global phylogeny and biogeography based on bioinformatics (2) screen for tardigrades in select locations of northern Sweden and compare with other Swedish locations, and (3) identify at least one tardigrade from northern Sweden and explore the published biomarkers for further identification. The bulk of this thesis was based on evaluation of the Silva database for analyzing SSU (small subunit) and LSU (large subunit) tardigrade sequences and create phylogenetic trees. Some initial lab work was performed using samples of moss and lichen from Piteå, Vindeln and Öland. Results show that only few countries have been explored with regard to tardigrades, and in Sweden more research have been performed in the south compared to the north. The phylogenetic trees give a rough overview of tardigrade relatedness but many of the sequences need to be improved and more sequence work from additional environments is needed. In the lab tardigrades were only found from the Piteå samples, and one of those was identified as Macrobiotus hufelandi, for which a new biomarker was created. Overall, tardigrade research need to continue and expand to other regions in order to understand how these organisms differ between different environments, and more work is needed to ensure higher quality of sequences added to databases.

Tardigrades are microscopic animals that can survive exposure to multiple extreme conditions. This remarkable ability makes them suitable laboratory model organisms for conducting biological to astrobiological research. Whereas tardigrade extreme-tolerance research has been focused predominantly on their ability to endure extreme desiccation, responses to other extraordinary conditions (i.e. hypergravity, pH, radiation and low temperature) remain un-described. These extreme tolerance research areas, in addition to life history traits, were documented in our studies on the eutardigrade species Hypsibius dujardini. We found that specimens tolerated extreme g-equivalent forces (i.e., 16060g) and radiation levels (i.e. 5 kGy), with decreased survivorship at increased accelerations and radiation doses. Radiation induced bystander effects (RIBEs) manifested as a threshold response, with the threshold value between 3 and 5 kGy. Extreme acidic (pH 1 and 2) and alkaline (pH 11 to 14) conditions caused death instantaneously, while exposures to pH 4, 6, 8, 9, and 10 were tolerated. Tardigrade eggs reared at 0 °C for 4 days developed relatively slowly, diminishing their biological age relative to their chronological age. Extending cold exposure (0 °C) time (days = 10, 20 and 40) decreased incubation time (days = 3, 2 and 1, respectively) at 22 °C; lengthening cold exposure time led to decreased growth in juveniles and lowered survivorship in adults, suggesting that costs are associated with increasing incubation time at 0 °C. Tolerance to hypergravity, large radiation doses and a wide-range in pH conditions support the notion that tardigrades are suitable organisms for astrobiological research, particularly in exploring parameters associated with potential transfer and habitability in extreme environments. RIBEs in adult tardigrades and the ability for tardigrade embryos to alter their ‘biological clocks’ based on exposed cold temperature duration have applications in biological research. Characterizing molecules involved in bystander signaling and response and biological clock adjustments during development could have important implications for improving biological practices such as radiotherapy and cryopreservation. / Thesis / Doctor of Philosophy (PhD) / While interest in tardigrade extreme tolerance research has increased over the last decade, many research areas continue to be underrepresented or non- existent. And, while recognized tardigrade species have been increasing steadily in number, fundamental biological details, like individual life history traits, remain unknown for most. The main objectives in this thesis therefore were to survey the life history traits for the freshwater tardigrade species Hypsibius dujardini, increase knowledge about its extreme-tolerance abilities and describe its utility in astrobiological and biological studies. Research involved tardigrade tolerance to hypergravity, pH levels and radiation exposure (and associated radiation-induced bystander effects) as well as responses to temperature changes during development. Findings reported in this dissertation provide new data about H. dujardini, thereby narrowing the information gap that currently exists in the literature for this species.

Foi realizado um estudo das relações filogenéticas de Stygarctidae e Digitopoda (Tardigrada, Archaeotardigrada, Macrocephala) seguindo-se os princípios e métodos henniguianos. Foram selecionados na literatura os caracteres morfológicos utilizados para os dois grupos: 61 caracteres (43 binários e 18 multiestado) para 17 táxons terminais, de Stygarctidae, ao nível de espécie, e 40 caracteres (31 binários e 9 multiestado) para 10 táxons superiores de Digitopoda. As análises manuais produziram cladogramas totalmente resolvidos com 101 passos evolutivos e índice de consistência 0,86 para Stygarctidae, e 79 passos evolutivos e índice de consistência 0,63 para Digitopoda. Também foram feitas análises numéricas, com o auxílio do programa Hennig 86, comparando-se os resultados destas com as análises manuais. O algoritmo utilizado foi o mhennig*. O consenso de duas árvores de Stygarctidae apresentou topologia idêntica à do cladograma supracitado, com 98 passos evolutivos, índice de consistência 0,77 e índice de retenção 0,82. No caso de Digitopoda, o consenso de duas árvores apresentou uma topologia radicalmente diferente do resultado manual, com 66 passos evolutivos, índice de consistência 0,68 e índice de retenção 0,63. Também foram analisados dois caracteres multiestado, cada um com duas condições apomórficas, para três táxons terminais (nível de espécie) de Orzeliscinae. Neste caso, o cladograma obtido apresentou quatro passos evolutivos e índice de consistência 1. Stygarctidae foi mantido como táxon monofilético, apresentando a seguinte topologia entre os seus gêneros: ((Parastygarctus + Stygarctus) + ((Mesostygarctus + Pseudostygarctus) + Megastygarctides)). Digitopoda foi subdividido em dois táxons monofiléticos, apresentando a seguinte topologia: (Neostygarctus + (Neostygarctus + Batillipes + (Batillipes + (Halechiniscinae + Orzeliscinae) + ((Halechiniscinae + Orzeliscinae) + Dipodarctus + (Dipodarctus + (Floractinae + Tanarctinae))))) + Renaudarctus + (Renaudarctus + (Euclavarctinae + Styraconyxinae))). Halechiniscidae não é monofilético e Halechiniscinae é um táxon mais restrito, que inclui apenas Halechiniscus e Chrysoarctus. Orzeliscinae é redefinido de forma a incluir Paradoxipus, grupo-irmão de Opydorscus + Orzeliscus. Styraconyxinae inclui também Archechiniscus. Archechiniscinae não é válido. Neostygarctidae, Renaudarctidae, Neoarctidae e Megastygarctidinae foram eliminados do sistema de Tardigrada / Relationships among the subgroups of Stygarctidae and Digitopoda (Tardigrada, Archaeotardigrada, Macrocephala) were invetigated according to hennigian principles and methods. Morphological characters were selected from the literature for these two groups: 61 characters (43 binary and 18 multistate) for 17 species of Stygarctidae and 40 characters (31 binary and 9 multistate) for 10 major groups of Digitopoda. Manual analysis produced fully resolved cladograms with 101 evolutionary steps and consistency index = 0,86 for Stygarctidae, and 79 evolutionary steps and consistency index = 0,63 for Digitopoda. Numerical analysis were done using the software Hennig 86, for comparison with manual analysis. The algoritm mhennig* was used. The consensus tree of two Stygarctidae trees showed identical topology with the manual cladogram, with 98 evolutionary steps, consistency index = 0,77 and retention index = 0,82. The consensus tree of two Digitopoda trees showed a complete different topology from the manual cladogram, with 66 evolutionary steps, consistency index = 0,68 and retention index = 0,63. There were also analysed two multistate characters, each one with two apomorphic conditions, for three Orzeliscinae species. In this case, another fully resolved cladogram with four evolutionary steps and consistency index = 1 was obtained. Stygarctidae was maintained as a monophyletic taxon, showing the following system for its genera: ((Parastygarctus + Stygarctus) + ((Mesostygarctus + Pseudostygarctus) + Megastygarctides)). Digitopoda, branched into two monophyleitc taxa, showed the following system: (Neostygarctus + (Neostygarctus + Batillipes + (Batillipes + (Halechiniscinae + Orzeliscinae) + ((Halechiniscinae + Orzeliscinae) + Dipodarctus + (Dipodarctus + (Floractinae + Tanarctinae))))) + Renaudarctus + (Renaudarctus + (Euclavarctinae + Styraconyxinae))). Halechiniscidae is not a monophyletic taxon and Halechiniscinae is a more inclusive taxon comprising only Halechiniscus e Chrysoarctus. Orzeliscinae includes Paradoxipus, the sistergroup of Opydorscus + Orzeliscus. Styraconyxinae is monophyletic with the inclusion of Archechiniscus. Archechiniscinae is not valid. Neostygarctidae, Renaudarctidae, Neoarctidae and Megastygarctidinae are not supported in the system of the Tardigrada

Foi realizado um estudo das relações filogenéticas de Stygarctidae e Digitopoda (Tardigrada, Archaeotardigrada, Macrocephala) seguindo-se os princípios e métodos henniguianos. Foram selecionados na literatura os caracteres morfológicos utilizados para os dois grupos: 61 caracteres (43 binários e 18 multiestado) para 17 táxons terminais, de Stygarctidae, ao nível de espécie, e 40 caracteres (31 binários e 9 multiestado) para 10 táxons superiores de Digitopoda. As análises manuais produziram cladogramas totalmente resolvidos com 101 passos evolutivos e índice de consistência 0,86 para Stygarctidae, e 79 passos evolutivos e índice de consistência 0,63 para Digitopoda. Também foram feitas análises numéricas, com o auxílio do programa Hennig 86, comparando-se os resultados destas com as análises manuais. O algoritmo utilizado foi o mhennig*. O consenso de duas árvores de Stygarctidae apresentou topologia idêntica à do cladograma supracitado, com 98 passos evolutivos, índice de consistência 0,77 e índice de retenção 0,82. No caso de Digitopoda, o consenso de duas árvores apresentou uma topologia radicalmente diferente do resultado manual, com 66 passos evolutivos, índice de consistência 0,68 e índice de retenção 0,63. Também foram analisados dois caracteres multiestado, cada um com duas condições apomórficas, para três táxons terminais (nível de espécie) de Orzeliscinae. Neste caso, o cladograma obtido apresentou quatro passos evolutivos e índice de consistência 1. Stygarctidae foi mantido como táxon monofilético, apresentando a seguinte topologia entre os seus gêneros: ((Parastygarctus + Stygarctus) + ((Mesostygarctus + Pseudostygarctus) + Megastygarctides)). Digitopoda foi subdividido em dois táxons monofiléticos, apresentando a seguinte topologia: (Neostygarctus + (Neostygarctus + Batillipes + (Batillipes + (Halechiniscinae + Orzeliscinae) + ((Halechiniscinae + Orzeliscinae) + Dipodarctus + (Dipodarctus + (Floractinae + Tanarctinae))))) + Renaudarctus + (Renaudarctus + (Euclavarctinae + Styraconyxinae))). Halechiniscidae não é monofilético e Halechiniscinae é um táxon mais restrito, que inclui apenas Halechiniscus e Chrysoarctus. Orzeliscinae é redefinido de forma a incluir Paradoxipus, grupo-irmão de Opydorscus + Orzeliscus. Styraconyxinae inclui também Archechiniscus. Archechiniscinae não é válido. Neostygarctidae, Renaudarctidae, Neoarctidae e Megastygarctidinae foram eliminados do sistema de Tardigrada / Relationships among the subgroups of Stygarctidae and Digitopoda (Tardigrada, Archaeotardigrada, Macrocephala) were invetigated according to hennigian principles and methods. Morphological characters were selected from the literature for these two groups: 61 characters (43 binary and 18 multistate) for 17 species of Stygarctidae and 40 characters (31 binary and 9 multistate) for 10 major groups of Digitopoda. Manual analysis produced fully resolved cladograms with 101 evolutionary steps and consistency index = 0,86 for Stygarctidae, and 79 evolutionary steps and consistency index = 0,63 for Digitopoda. Numerical analysis were done using the software Hennig 86, for comparison with manual analysis. The algoritm mhennig* was used. The consensus tree of two Stygarctidae trees showed identical topology with the manual cladogram, with 98 evolutionary steps, consistency index = 0,77 and retention index = 0,82. The consensus tree of two Digitopoda trees showed a complete different topology from the manual cladogram, with 66 evolutionary steps, consistency index = 0,68 and retention index = 0,63. There were also analysed two multistate characters, each one with two apomorphic conditions, for three Orzeliscinae species. In this case, another fully resolved cladogram with four evolutionary steps and consistency index = 1 was obtained. Stygarctidae was maintained as a monophyletic taxon, showing the following system for its genera: ((Parastygarctus + Stygarctus) + ((Mesostygarctus + Pseudostygarctus) + Megastygarctides)). Digitopoda, branched into two monophyleitc taxa, showed the following system: (Neostygarctus + (Neostygarctus + Batillipes + (Batillipes + (Halechiniscinae + Orzeliscinae) + ((Halechiniscinae + Orzeliscinae) + Dipodarctus + (Dipodarctus + (Floractinae + Tanarctinae))))) + Renaudarctus + (Renaudarctus + (Euclavarctinae + Styraconyxinae))). Halechiniscidae is not a monophyletic taxon and Halechiniscinae is a more inclusive taxon comprising only Halechiniscus e Chrysoarctus. Orzeliscinae includes Paradoxipus, the sistergroup of Opydorscus + Orzeliscus. Styraconyxinae is monophyletic with the inclusion of Archechiniscus. Archechiniscinae is not valid. Neostygarctidae, Renaudarctidae, Neoarctidae and Megastygarctidinae are not supported in the system of the Tardigrada

The story of the Tardigrada Symposia began 35years ago in Pallanza, Italy. It was an idea of Professor Livia Tonolli, who wanted to honour Professor Giuseppe Ramazzotti, at that time the authority in that scientific field and her friend. Considering that tardigrades are a neglected group of metazoans (still to date), this particular event could be finished with that occasion, but it has not been so. With some gaps, the meetings have been proceeded till now, promoting scientific exchange among the researchers and improving the research quality. Following these 35years and the topics of the symposia, we can understand the changing in the scientific approach. Taxonomy and faunal studies were the predominant topics of the first symposium, but also ultrastructural morphology, ecology, physiology, cytotaxonomy and reproductive biology were represented. Furthermore, the studies by SEM moved their first steps in that occasion. Faunal and taxonomic studies represented often the main topic during the years, but also other kinds of researches involving phylogeny, physiology, ultrastructure of organs and cells always accompanied it. From these points of view, often tardigrades were compared with other animal groups, giving a wider sense to the research. Molecular aspects were already considered in the third symposium (1980, Tennessee), but reconsidered only in the symposium in Cambridge (1994) and developed from the symposium in Denmark (2000). The last symposia showed an increased number of participants and scientific contributions. In line with the increasingly international nature of publications, the quality of the proceedings has also increased, always using in the last 10years qualified international journals with peer review and impact factor, as now required by young scientists to further their careers.

<p> The search for life on other planets has brought with it a renewed interest in the study of extremophiles as it relates to cold-tolerance. The means for the elucidation of these studies has been through the use of analog-sites in the polar regions of Earth as approximations of extra-planetary environments. These extreme environments are typified by low annual temperatures, low levels of available liquid water, food and light. Despite these conditions, however, life prevails. Perhaps one of the most "extreme" organisms residing in these environments are tardigrades. These micrometazoans are capable of withstanding temperature extremes from 150°C to -276°C, pressure, X-ray radiation, dessication and salinity. Of relevance to this thesis is the ability of the tardigrade to withstand extreme low temperature, which they do by entering a cryobiotic, or latent state. Cryobiosis is seen as an extreme form of cold-tolerance, but apparently lacking a lower lethal temperature (LL T). Despite the incredible advantages that this strategy confers, cryobiosis remains poorly understood. This study provides a review of the literature on freeze tolerance and cryobiosis to bridge the two spheres of research, as well as clarifying the nomenclature used in these papers. Particular attention is paid to the terms of cryoprotective dehydration and cryobiosis, proposing that cryoprotective dehydration be thought of instead as a process leading to the latent state. Experiments were conducted to explore the relationship that time and temperature have on cryobiotic capability in the tardigrade Macrobiotus harmsworthii. Results showed that both time and temperature played a significant role above -80°C, with poor survivability at -20°C. At -80°C, however, time no longer appeared to play a role in viability. </p> / Thesis / Master of Science (MSc)

No description available.

1. Tardigrades comprise a micrometazoan phylum that is a sister group of the arthropods. 2. They are components of the meiobenthos in lotic habitats, and ≃ 50-70 species have been reported in such habitats world-wide. Approximately 800 species have been identified from all marine, freshwater, and terrestrial habitats. 3. Taxonomy is based primarily on the morphology of the claws, buccal-pharyngeal apparatus, cuticle and eggs. 4. Reproductive modes include sexual reproduction (amphimixis) and parthenogenesis. The sexual condition of individuals may be either gonochorism, unisexuality, or hermaphroditism. Moulting occurs throughout the life of the tardigrade. 5. Latent states (cryptobiosis, including encystment, anoxybiosis, cryobiosis, osmobiosis and anhydrobiosis) enable tardigrades to withstand unfavourable environmental conditions. 6. Population densities, life histories, dissemination and biogeography of freshwater species are poorly known.