A New Species of Bisexual Milnesium (Eutardigrada: Apochela) Having Aberrant Claws from Innhovde, Dronning Maud Land, East Antarctica.

There have been several records in the last 60 years for East Antarctica for Milnesium tardigradum Doyère, 1840 sensu lato, now considered a species complex. During the 56th Japanese Antarctic Research Expedition summer operation (2014-2015), a new tardigrade species in the genus Milnesium Doyère, 1840 was found in an ice-free Innhovde area along Lützow-Holm Bay, Dronning Maud Land, East Antarctica. The new species has aberrant claws with four to seven points on each secondary claw branch, which distinguishes it from other Milnesium species. A male specimen was found in the population and evidence showed that an isolated adult female moulted twice without oviposition. This strongly suggested bisexual reproduction for this population. The new species, Milnesium rastrum sp. nov., is described with its phylogenetic position and a discussion on the reproductive strategies for the harsh environments.

Annotated zoogeography of non-marine Tardigrada. Part I: Central America.

Dividing the world into nine regions, this first paper describes literature records of the limno-terrestrial tardigrades (Tardigrada) reported from Central America. Updating previously published species lists we have revised the taxonomy and provided additional habitat, geographic co-ordinates, and biogeographic comments. It is hoped this work will serve as a reference point and background for further zoogeographic studies.

Annotated zoogeography of non-marine Tardigrada. Part V: Australasia.

This paper is the fifth monograph of the series that describes the global records of limno-terrestrial water bears (Tardigrada). Here, we provide a comprehensive list of non-marine tardigrades recorded from Australasia, providing an updated and revised taxonomy accompanied by geographic co-ordinates, habitat, and biogeographic comments. It is hoped this work will serve as a reference point and background for further zoogeographical and taxonomical studies.

20 years of Zootaxa: Tardigrada (Ecdysozoa: Panarthropoda).

Over the last two decades, Zootaxa has hosted nearly 200 papers concerning tardigrade taxonomy, systematics, phylogeny, and evolution. A total of 160 researchers from all continents (except the Antarctic) published descriptions of almost 200 new taxa, mostly species, but also genera and higher taxonomic ranks, such as families and superfamilies. This editorial is dedicated to the late Professor Clark W. Beasley who was the first tardigrade Associate Editor for Zootaxa.

Integrative description of a new Dactylobiotus (Eutardigrada: Parachela) from Antarctica that reveals an intraspecific variation in tardigrade egg morphology.

Tardigrades constitute one of the most important group in the challenging Antarctic terrestrial ecosystem. Living in various habitats, tardigrades play major roles as consumers and decomposers in the trophic networks of Antarctic terrestrial and freshwater environments; yet we still know little about their biodiversity. The Eutardigrada is a species rich class, for which the eggshell morphology is one of the key morphological characters. Tardigrade egg morphology shows a diverse appearance, and it is known that, despite rare, intraspecific variation is caused by seasonality, epigenetics, and external environmental conditions. Here we report Dactylobiotus ovimutans sp. nov. from King George Island, Antarctica. Interestingly, we observed a range of eggshell morphologies from the new species, although the population was cultured under controlled laboratory condition. Thus, seasonality, environmental conditions, and food source are eliminated, leaving an epigenetic factor as a main cause for variability in this case.

Phylum Tardigrada: an "individual" approach.

Phylum Tardigrada consists of ∼1000 tiny, hardy metazoan species distributed throughout terrestrial, limno-terrestrial and oceanic habitats. Their phylogenetic status has been debated, with current evidence placing them in the Ecdysozoa. Although there have been efforts to explore tardigrade phylogeny using both morphological and molecular data, limitations such as their few morphological characters and low genomic DNA concentrations have resulted in restricted taxonomic coverage. Using a protocol that allows us to identify and extract DNA from individuals, we have sequenced 18S rDNA from 343 tardigrades from across the globe. Using maximum parsimony and Bayesian analyses we have found support for dividing Order Parachela into three super-families and further evidence that indicates the traditional taxonomic perspective of families in the class Eutardigrada are nonmonophyletic and require re-working. It appears that conserved morphology within Tardigrada has resulted in conservative taxonomy as we have found cases of several discrete lineages grouped into single genera. Although this work substantially adds to the understanding of the evolution and taxonomy of the phylum, we highlight that inferences gained from this work are likely to be refined with the inclusion of further taxa-specifically representatives of the nine families yet to be sampled. © The Willi Hennig Society 2008.

Assessing meiofaunal variation among individuals utilising morphological and molecular approaches: an example using the Tardigrada.

BACKGROUND: Meiofauna - multicellular animals captured between sieve size 45 mum and 1000 mum - are a fundamental component of terrestrial, and marine benthic ecosystems, forming an integral element of food webs, and playing a critical roll in nutrient recycling. Most phyla have meiofaunal representatives and studies of these taxa impact on a wide variety of sub-disciplines as well as having social and economic implications. However, studies of variation in meiofauna are presented with several important challenges. Isolating individuals from a sample substrate is a time consuming process, and identification requires increasingly scarce taxonomic expertise. Finding suitable morphological characters in many of these organisms is often difficult even for experts. Molecular markers are extremely useful for identifying variation in morphologically conserved organisms. However, for many species markers need to be developed de novo, while DNA can often only be extracted from pooled samples in order to obtain sufficient quantity and quality. Importantly, multiple independent markers are required to reconcile gene evolution with species evolution. In this primarily methodological paper we provide a proof of principle of a novel and effective protocol for the isolation of meiofauna from an environmental sample. We also go on to illustrate examples of the implications arising from subsequent screening for genetic variation at the level of the individual using ribosomal, mitochondrial and single copy nuclear markers. RESULTS: To isolate individual tardigrades from their habitat substrate we used a non-toxic density gradient media that did not interfere with downstream biochemical processes. Using a simple DNA release technique and nested polymerase chain reaction with universal primers we were able amplify multi-copy and, to some extent, single copy genes from individual tardigrades. Maximum likelihood trees from ribosomal 18S, mitochondrial cytochrome oxidase subunit 1, and the single copy nuclear gene Wingless support a recent study indicating that the family Hypsibiidae is a non-monophyletic group. From these sequences we were able to detect variation between individuals at each locus that allowed us to identify the presence of cryptic taxa that would otherwise have been overlooked. CONCLUSION: Molecular results obtained from individuals, rather than pooled samples, are a prerequisite to enable levels of variation to be placed into context. In this study we have provided a proof of principle of this approach for meiofaunal tardigrades, an important group of soil biota previously not considered amenable to such studies, thereby paving the way for more comprehensive phylogenetic studies using multiple nuclear markers, and population genetic studies.

Annotated zoogeography of non-marine Tardigrada. Part III: North America and Greenland.

This paper is the third monograph of the series that describes the global records of limno-terrestrial water bears (Tardigrada). Here, we provide a comprehensive list of non-marine tardigrades recorded from the North America, providing an updated and revised taxonomy accompanied by geographic co-ordinates, habitat, and biogeographic comments. It is hoped this work will serve as a reference point and background for further zoogeographical and taxonomical studies.

Annotated zoogeography of non-marine Tardigrada. Part II: South America.

This paper is the second monograph of nine that describes the global records of limno-terrestrial water bears (Tardigrada). Here, we provide a comprehensive list of non-marine tardigrades recorded from South America, providing an updated and revised taxonomy accompanied by geographic co-ordinates, habitat, and biogeographic comments. It is hoped this work will serve as a reference point and background for further zoogeographical and taxonomical studies.

New species in the Old World: Europe as a frontier in biodiversity exploration, a test bed for 21st century taxonomy.

The number of described species on the planet is about 1.9 million, with ca. 17,000 new species described annually, mostly from the tropics. However, taxonomy is usually described as a science in crisis, lacking manpower and funding, a politically acknowledged problem known as the Taxonomic Impediment. Using data from the Fauna Europaea database and the Zoological Record, we show that contrary to general belief, developed and heavily-studied parts of the world are important reservoirs of unknown species. In Europe, new species of multicellular terrestrial and freshwater animals are being discovered and named at an unprecedented rate: since the 1950s, more than 770 new species are on average described each year from Europe, which add to the 125,000 terrestrial and freshwater multicellular species already known in this region. There is no sign of having reached a plateau that would allow for the assessment of the magnitude of European biodiversity. More remarkably, over 60% of these new species are described by non-professional taxonomists. Amateurs are recognized as an essential part of the workforce in ecology and astronomy, but the magnitude of non-professional taxonomist contributions to alpha-taxonomy has not been fully realized until now. Our results stress the importance of developing a system that better supports and guides this formidable workforce, as we seek to overcome the Taxonomic Impediment and speed up the process of describing the planetary biodiversity before it is too late.