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Orthops is a widely distributed plant bug genus comprising 35 species. Its nominotypical subgenus includes seven species mostly known from the Palearctic, and four of them are widely distributed. Most of them live in sympatry having only little morphological differences. The species limits have never been tested using the molecular data. The aim of this work is to test whether currently defined species represent monophyletic lineages and to find their interrelationships using an integrative approach. Morphological studies on external characters and male and female genitalia were performed. The molecular studies were based on the mitochondrial (cytochrome c oxidase subunit I [COI] and 12S ribosomal RNA [rRNA]) and nuclear (internal transcribed spacer I [ITS1] and calcium ATPase [Ca‐ATPase]) markers and included comparison of the intra‐ and interspecific distances, species delimitation (ABGD, BPP, bGMYC, PTP, and bPTP), and phylogenetic analyses. All markers showed interspecific differences, and COI was the most variable. It was found that all species differed from each other morphologically, and the most reliable character complexes were parameres and female genitalia. In most analyses, Orthops kalmii and O. campestris were monophyletic. Orthops basalis formed a clade in most phylogenetic trees. Most of the species delimitation analyses confirmed the status of those three species. Orthops scutellatus was split into two clades, Palearctic and North American, which was also confirmed by the species delimitation analyses. Those two groups differed in parameres. Orthops campestris and O. scutellatus form a clade in all analyses, and O. basalis forms a clade with O. kalmii in most analyses. [ABSTRACT FROM AUTHOR]

The aim of this study was to understand the systematic relationships between certain fish genera with oromandibular discs in the Labeoninae. At the same time, this was an opportunity to clarify the taxonomic status of certain species in the genera Ageneiogarra, Garra, Placocheilus, and other taxa distributed in China. Morphological comparison and molecular analysis were used in the study. The results showed that the genera with oromandibular discs had no recent common ancestor and that their oromandibular discs were the result of convergent evolution in different evolutionary lineages. Due to the homogeneity of their habitats, these fish have evolved oromandibular discs with similar appearance and structure. Both morphological and molecular evidence suggests that (1) Placocheilus cryptonemus distributed in the Nu‐Jiang (the Upper Salween River Basin), Yunnan, China, represent a new genus, here described as Pseudoplacocheilus, and (2) Garra micropulvinus occurring in the Panlong‐He (the upper portion of the Lo River, a branch of the Red River Basin) from Wenshan, Yunnan, represents another new genus, here described as Supradiscus. [ABSTRACT FROM AUTHOR]

In the phylum Tardigrada, as in other meiofauna taxa, the small size of the animals and the paucity of morphological characters useful for taxonomy present a challenge for systematic studies. For this reason, an integrated approach is increasingly desirable, including at least morphology, morphometry and molecular investigations, and possibly reproductive biology, ecology, physiology and other approaches. In this light, we analysed different populations of Macrobiotus (Eutardigrada, Macrobiotidae) from Italy, France and Poland with persimilis type of eggs and with very similar animals. We compared the morphology and morphometry of the type materials of Macrobiotus persimilis and Macrobiotus polonicus with those of newly collected populations, which were also analysed from a molecular (cox1 mtDNA and 18S rDNA) and reproductive perspective. Our data confirmed the presence of a persimilis-polonicus complex, recognizable by very similar characters of the animals and the eggs. It comprises M. persimilis, M. polonicus, four new morphologically distinguishable species described in this paper (Macrobiotus dolosus sp. nov., Macrobiotus siderophilus sp. nov., Macrobiotus fontourai sp. nov., Macrobiotus muralis sp. nov.) and other species very similar from a morphological point of view. Molecular data, retrieved for the first three new species, reveal that they have very high genetic distances for cox1 (16.0–17.7%). Furthermore, we have been able to verify that more than one species of this complex can cohabit in the same moss. A wider persimilis group, comprising the persimilis-polonicus complex, could also be identified only on morphological basis. [ABSTRACT FROM AUTHOR]

Pseudechiniscus is the second most species-rich genus in Heterotardigrada and in the family Echiniscidae. However, previous studies have pointed out polyphyly and heterogeneity in this taxon. The recent erection of the genus Acanthechiniscus was another step in making Pseudechiniscus monophyletic, but species identification is still problematic. The present investigation aims at clarifying biodiversity and taxonomy of Pseudechiniscus taxa, with a special focus on species pertaining to the so-called ' suillus – facettalis group', by using an integrated approach of morphological and molecular investigations. The analysis of sequences from specimens sampled in Europe and Asia confirms the monophyly of the genus Pseudechiniscus. Inside the genus, two main evolutionary lineages are recognizable: the P. novaezeelandiae lineage and the P. suillus–facettalis group lineage. Inside the P. suillus–facettalis group, COI molecular data points out a very high variability between sampled localities, but in some cases also among specimens sampled in the same locality (up to 33.3% p-distance). The integrated approach to the study of Pseudechiniscus allows confirmation of its monophyly and highlights the relationships in the taxon, pointing to its global distribution. [ABSTRACT FROM AUTHOR]

The underestimation of biodiversity and scarce knowledge of the biogeographic distributions of terrestrial meiofaunal component limit our understanding of the origin of Antarctic fauna. One of its main components is tardigrades; nonetheless studies on tardigrade diversity are still few in the continental Antarctic area. In order to increase our knowledge of the underreported terrestrial meiofaunal communities within continental Antarctica, as well as to provide new information for biogeographic and evolutionary analysis of these communities, the tardigrade diversity of 11 samples collected along the coast of Victoria Land was considered. The application of an integrative approach in which morphological (Light – LM, scanning electron – SEM, and confocal laser scanning microscopy – CSLM) and molecular analysis (18S, 28S, cox1 genes) were combined allowed us to characterize the tardigrade fauna inhabiting mosses, lichens, and cyanobacterial mats of Victoria Land. These analyses allowed the detection of two tardigrade species new to science (Cryoconicus antiarktos sp. nov., Ramazzottius sabatiniae sp. nov.), and the emendation of known species ((Hebesuncus ryani Dastych and Harris, 1994, Ramazzottius nivalis Dastych, 2006, Cryoconicus ljudmilae comb. nov. (Biserov, 1997/98), and Cryoconicus cataphractus (Maucci, 1974)), together with the genus Cryoconicus. The Ramazzottius type of claws was redefined identifying three subtypes. Also, we investigated the phylogenetic position of some problematic/unresolved lineages all belonging to the family Ramazzottiidae. These data increased the knowledge of the biodiversity in Victoria Land, the number of endemic tardigrades in Antarctica, and provided evidence on the origin of Antarctic endemism. Lastly, new methods for integrative taxonomic studies on tardigrades were presented and discussed. [ABSTRACT FROM AUTHOR]

Species of the genus Bertolanius (Eohypsibiidae, Eohypsibioidea) are morphologically very similar and can be distinguished by only minute differences. During faunal surveys in Arctic areas (Disko I., Greenland; Uummannaq, Greenland; Abisko, Sweden), the four species Bertolanius nebulosus, Bertolanius smreczynskii, Bertolanius weglarskae and Bertolanius birnae sp. nov. were found. Bertolanius nebulosus and Bertolanius smreczynskii have been compared with their paratypes, and type material of other species of Bertolanius has been considered for comparison within the genus. Bertolanius birnae sp. nov. possesses a unique combination of characters (i.e., an evident anterior band of teeth, the median ridge of the buccal armature consisting of two large teeth instead of one, absence of eyes, and eggs with conical processes without areolation around their bases) that is not seen in any other species in the genus, though these characters may be present in other combinations within the genus. Our revision and analytical comparison among these Bertolanius species adds new and important information on claw, buccal armature, egg surface morphologies as well as the encystment process of the species. We also provide a taxonomic key to aid the identification of Bertolanius species. The new discoveries of Bertolanius species from northern polar regions further support the hypothesis that the distribution of Eohypsibioidea is restricted to the Holarctic in the Arctic and Periarctic areas, or in alpine areas between 550 and 2400 m a.s.l. of more temperate regions. [ABSTRACT FROM AUTHOR]

Eutardigrada systematics relies mainly on the morphology of the sclerified structures of the animals. In particular, the main division of Parachela into four superfamilies relies heavily upon claw morphology; however, this character, alone, may be either inadequate or useless for tardigrades with no claws, or when secondary claw branches are reduced or absent, as in the case of species belonging to the genus Haplomacrobiotus. This is a very uncommon genus, so far reported only in North America. The systematic position of this genus has been debated since its description, having first been placed in the family Macrobiotidae (Macrobiotoidea) and then in the family Calohypsibiidae (Hypsibioidea). Currently, the position of the supposedly related genus Hexapodibius is still debated, being attributed to Isohypsibiidae (Isohypsibioidea) or to Calohypsibiidae (Hypsibioidea), i.e. to two different superfamilies. The morphological (light and electron microscopy), chemical (X-ray spectroscopy), and molecular ( 18S and 28S genes) analyses of a population of Haplomacrobiotus utahensis Pilato & Beasley, 2005 from Snow Canyon State Park (Utah, USA) allowed us to validate the position of this genus within Isohypsibioidea. Our integrated findings placed Haplomacrobiotus in a close relationship with the genus Hexapodibius, and allowed us to erect the new family Hexapodibiidae, comprising the genera Hexapodibius, Parhexapodibius, Haplomacrobiotus, and Haplohexapodibius. [ABSTRACT FROM AUTHOR]

Important contributions have been made to the systematics of Eutardigrada in recent years, but these have also revealed that several taxa are polyphyletic and that cryptic species are present. To shed light on the taxonomy and systematic position of the genus Richtersius (Eutardigrada, Macrobiotoidea), six populations attributed to Richtersius coronifer were collected and analysed from morphological (light and scanning electron microscopy) and molecular ( mitochondrial cytochrome oxidase subunit 1, 18S, 28S) points of view. In particular, a new morphometric index (claw common tract: length of the common tract of the claw/total claw length × 100) and a new morphological character (stalk system) were introduced. Our integrative study was able to unveil the 'cryptic' species diversity within Richtersius, showing that the genus contains more than one evolutionary lineage. A morphological peculiarity in the animals of all lineages is the dimorphism in the morphology of the cuticle. Cuticular pores are present in the newborns and are lost with the first moult; this morphological change represents a novelty in the life cycle of eutardigrades. The phylogenetic analyses carried out on Richtersius populations and other Macrobiotoidea show that Richtersius is closely related to Macrobiotus islandicus, whereas Adorybiotus granulatus is more related to Richtersius and M. islandicus than to other members of the genus Macrobiotus (type genus of Macrobiotidae); therefore, the genus Macrobiotus and the family Macrobiotidae are not monophyletic. Based on these results, the new genus Diaforobiotus (for M. islandicus) and the new family Richtersiidae (composed of Richtersius, Diaforobiotus gen. nov., and Adorybiotus) are established. [ABSTRACT FROM AUTHOR]

Symbiosis can be defined as an interaction between individuals of different biological species. Despite the small number of studies solely devoted to symbiotic interactions between tardigrades and micro-organisms (such as bacteria, fungi and protozoans), numerous reports can be found in the literature, especially as notes in faunal and alpha-taxonomy studies. Here, we review the literature and compile a list of the interactions between tardigrades and micro-organisms, excluding those that constitute food for tardigrades. Furthermore, a genetic study on a tardigrade symbiophoront, the ciliate Pyxidium tardigradum van der Land, 1964 was performed. There are a few records of P. tardigradum on both European and Asian tardigrades, but no morphological discrepancies among populations have been observed. We present here the phylogenetic positioning for P. tardigradum inferred by using nuclear ribosomal markers (18S and 5.8S). The phylogenetic trees showed all P. tardigradum specimens grouped together, and belonging to the family Operculariidae, order Operculariida. Moreover, a study based on the genetic distances between a Portuguese and an Irish population of P. tardigradum was performed using internal transcribed spacers ITS1 and ITS2. The ITS1 and ITS2 sequences showed differences between populations, leading us to hypothesize the presence of cryptic species. [ABSTRACT FROM AUTHOR]

Antarctica is an ice-dominated continent and all its terrestrial and freshwater habitats are fragmented, which leads to genetic divergence and, eventually, speciation. Acutuncus antarcticus is the most common Antarctic tardigrade and its cryptobiotic capabilities, small size and parthenogenetic reproduction present a high potential for dispersal and colonisation. Morphological (light and electron microscopy, karyology) and molecular (18S rRNA and cytochrome c oxidase subunit I (COI) genes) analyses on seven populations of A. antarcticus elucidated the genetic diversity and distribution of this species. All analysed populations were morphologically indistinguishable and made up of diploid females. All specimens presented the same 18S rRNA sequence. In contrast, COI analysis showed higher variability, with most Victoria Land populations presenting up to five different haplotypes. Genetic distances between Victoria Land specimens and those found elsewhere in Antarctica were low, while distances between Dronning Maud Land and specimens from elsewhere were high. Our analyses show that A. antarcticus can still be considered a pan-Antarctic species, although the moderately high genetic diversity within Victoria Land indicates the potential for speciation events. Regions of Victoria Land are considered to have been possible refugia during the last glacial maximum and a current biodiversity hotspot, which the populations of A. antarcticus mirror with a higher diversity than in other regions of Antarctica. [ABSTRACT FROM AUTHOR]

Tardigrades represent one of the most abundant groups of Antarctic metazoans in terms of abundance and diversity, thanks to their ability to withstand desiccation and freezing; however, their biodiversity is underestimated. Antarctic tardigrades from Dronning Maud Land and Victoria Land were analysed from a morphological point of view with light microscopy and scanning electron microscopy, and from a molecular point of view using two genes (18S, 28S) analysed in Bayesian inference and maximum-likelihood frameworks. In addition, indel-coding datasets were used for the first time to infer tardigrade phylogenies. We also compared Antarctic specimens with those from Italy and Greenland. A combined morphological and molecular analysis led to the identification of two new evolutionary lineages, for which we here erect the new genera Acanthechiniscus, gen. nov. (Echiniscidae, Echiniscoidea) and Mesobiotus, gen. nov. (Macrobiotidae, Macrobiotoidea). Moreover, two species new to science were discovered: Pseudechiniscus titianae, sp. nov. (Echiniscidae : Echiniscoidea) and Mesobiotus hilariae, sp. nov. (Macrobiotidae : Macrobiotoidea). This study highlights the high tardigrade diversity in Antarctica and the importance of an integrated approach in faunal and taxonomic studies. [ABSTRACT FROM AUTHOR]

The cuticular portion of the tardigrade feeding apparatus is a complex structure that can be schematically divided into four parts: a buccal ring, a buccal tube, a stylet system (formed by two piercing stylets, each within a stylet coat, and two stylet supports), and the lining of a myoepithelial sucking pharynx. To better understand the function and evolution of the feeding apparatus, the morpho-functional traits and chemical composition of the structures forming the feeding apparatuses of eight different species of tardigrades were analyzed. These eight species are representative of almost all main phylogenetic lineages of the phylum. The calcium and chitin in the feeding apparatus were examined by light microscopy, scanning electron microscopy, confocal laser scanning microscopy, energy dispersive X-ray spectroscopy, and Raman microspectroscopy (Raman). In all species, the feeding apparatus had been subjected to biomineralization due to CaCO3 encrustations organized in the crystalline form of aragonite. Aragonite and chitin are present in different concentrations in the feeding apparatus according to the structures and species considered. Generally, where the structures are rigid there is more aragonite than chitin, and vice versa. The buccal tube and piercing stylets are rich in calcium, with the piercing stylets apparently composed exclusively of aragonite. In eutardigrades, chitin is in higher concentration in the structures subject to higher mechanical stresses, such as the crests of the buccal crown and the condyles of the stylet furca. [ABSTRACT FROM AUTHOR]

Tardigrade feeding apparatus is a complex structure with considerable taxonomic significance that can be schematically divided into four parts: buccal ring, buccal tube, stylet system, and pharynx. We analyzed the fine morphology and the tridimensional organization of the tardigrade buccal-pharyngeal apparatus in order to clarify the relationships between form and function and to identify new characters for systematic and phylogenetic studies. We conducted a comparative analysis of the cuticular structures of the buccal-pharyngeal apparatuses of twelve eutardigrade species, integrating data obtained by SEM and LM observations. Morphological diversity was observed and new cuticular structures such as the stylet coat of the stylet system were identified. The synthesis of the buccal-pharyngeal apparatus during molting was also analyzed obtaining a clear developmental sequence of its resynthesis. These findings lead us to redefine the previous interpretations of the functioning mechanisms of the buccal-pharyngeal apparatus and provide a more specific relationship between tardigrade diet and the anatomy of their feeding apparatuses. In addition, the detection by energy-dispersive X-ray spectroscopy of calcium in the stylets, buccal tube, and placoids of eutardigrade species (i.e., Milnesium tardigradum, Paramacrobiotus richtersi) indicates that CaCO incrustations are not an exclusive feature of heterotardigrades and lead to suppose that this trait was present in the ancestors of both classes. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Zoological Systematics & Evolutionary Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Zoological Systematics & Evolutionary Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Zoological Systematics & Evolutionary Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Zoological Systematics & Evolutionary Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Morphological and molecular studies on a tardigrade species have been carried out to verify the possibility of using a DNA barcoding approach for species identification in this phylum. Macrobiotus macrocalix Bertolani & Rebecchi,1993 was chosen as the test species since it belongs to a group of species in which the taxonomy is quite problematic. Animals and eggs belonging to three Italian and one Swedish populations have been investigated. Both morphological and molecular analyses show that all the populations belong to the same species. The low genetic distances recorded among the studied populations (0.3–1.0%) and the high genetic distance (15.9–16.3%) between these populations and a closely related species confirm the possibility of identifying a specimen of this species by its cytochrome oxidase subunit I sequence. Data from other authors support our results indicating that DNA barcoding can be applied to tardigrades. With our protocols, we have obtained voucher specimens that enable us to show a correspondence between morphology and molecular data. [ABSTRACT FROM AUTHOR]

Stressful environmental conditions limit survival, growth and reproduction, or these conditions induce resting stages indicated as dormancy. Tardigrades represent one of the few animal phyla able to perform both forms of dormancy: quiescence and diapause. Different forms of cryptobiosis (quiescence) are widespread and well studied, while little attention has been devoted to the adaptive meaning of encystment (diapause). Our goal was to determine the environmental factors and token stimuli involved in the encystment process of tardigrades. The eutardigrade Amphibolus volubilis, a species able to produce two types of cyst (type 1 and type 2), was considered. Laboratory experiments and long-term studies on cyst dynamics of a natural population were conducted. Laboratory experiments demonstrated that active tardigrades collected in April produced mainly type 2 cysts, whereas animals collected in November produced mainly type 1 cysts, indicating that the different responses are functions of the physiological state at the time they were collected. The dynamics of the two types of cyst show opposite seasonal trends: type 2 cysts are present only during the warm season and type 1 cysts are present during the cold season. Temperature represents the environmental factor involved in induction, maintenance and termination of the cyst. We also obtained evidence that A. volubilis is able to perform both diapause and cryptobiosis, even overlapping the two phenomena. The induction phase of tardigrade encystment can be compared to the induction phase of insect diapause, also indicating an involvement of endogenous factors in tardigrade encystment. As in insect diapause, tardigrade encystment can be considered a diapausing state controlled by exogenous and endogenous stimuli. [ABSTRACT FROM AUTHOR]

Abstract: The discovery of a new population of the non-marine heterotardigrade Novechiniscus armadilloides from Utah, USA, allowed us to reanalyse the species by means of scanning electron microscopy and differential interference contrast microscopy. This analysis confirmed the presence of bar shaped, unpaired segmental plates and of a long filament E in addition to the filament A always present in the class Heterotardigrada. It also provided additional information on characters not explicitly cited in the previous descriptions of this monotypic genus, such as details of the head cirri and clavae, details of the buccal tube and pharyngeal bulb, sculpture of the dorso-lateral and leg plates, details of the claws. The population is bisexual, but no secondary sexual dimorphism was observed. The male and female gonopores were described. New characters such as red eyes and red body colour were used in analysing the phylogeny of the family Echiniscidae. The phylogeny and biogeography of non-marine heterotardigrades provide intriguing questions for further research. [Copyright &y& Elsevier]

The morphology, biology and geographic distribution of Hypsibius zetlandicus (Murray 1907) are considered. Scanning electron microscopy (SEM) and/or light microscopy (LM) analyses have been carried out on H. zetlandicus and the type species of Hypsibius: Hypsibius dujardini (Doyère 1840), with particular emphasis on the buccal–pharyngeal apparatuses. Some unusual characteristics of this apparatus in H. zetlandicus lead us to the erection of the new genus Borealibius, to which H. zetlandicus ( Borealibius zetlandicus comb. n.) is transferred. In the light of new discoveries of this species from polar, sub-polar and alpine regions, and based on the available bibliographic references, we hypothesize a boreo–alpine distribution for this species. The presence of traits that are unusual and rare (in other tardigrade species) have been observed whilst analyzing the reproductive biology and ecology of B. zetlandicus (i.e., the presence of hermaphroditism, parental care and the colonization of very different substrates). [ABSTRACT FROM AUTHOR]

A comparative study of life history traits of two clones ( CDMr01 and CDMr02) of a triploid thelytokous apomictic population of the eutardigrade Macrobiotus richtersi has been carried out. Both clones were reared under the same lab conditions: temperature of 14 °C, photoperiod of 12 h/12 h (L/D), and nematodes ad libitum as food. Statistical analysis of the life history traits considered has indicated interclonal variability. The two clones were significantly different in the number of eggs per clutch (fertility), number of eggs laid per female per life span (fecundity), hatching percentage of eggs and hatching time. Similarities between clones have been observed with regard to life span, total number of ovipositions per life span, and age at first oviposition. In addition, significant differences in hatching time, with eggs hatched over a long period, were found within each clone. Interclonal variability in life history traits indicated the effects of genetic factors, whereas intraclonal variability reflected the effects of environmental factors. The evolutionary and adaptive significance of the life history phenotypic variations is discussed. [ABSTRACT FROM AUTHOR]

Tardigrades have two forms of dormancy, namely cryptobiosis and encystment. The encystment is a form of diapause known for a limited number of species of tardigrades and still little studied. To increase the knowledge on encystment, two species of eutardigrades from Italy have been considered: the moss-dwelling Amphibolus volubilis (Eohypsibiidae), and the limnic Dactylobiotus parthenogeneticus (Murrayidae). Cysts have been collected in nature, or induced under laboratory conditions. In the latter case, it was possible to follow the several steps of encystment processes. Two different types of cyst (“type 1” and “type 2”) have been found in A. volubilis, while in D. parthenogeneticus only one type has been found. In general, the ovoid-shaped cysts are constituted by a series of cuticles surrounding the animals and resemble an onion or a Matrioshka Russian doll. In all three types of cyst, the encystment processes show both common and peculiar traits. Encystment begins with the discharging of the sclerified parts of the buccal-pharyngeal apparatus, as in the molting process, but without the loss of the old cuticle. Then, two or three new cuticles are serially synthesized, according to cyst type. In A. volubilis, the ultrastructure of these new cuticular involucra is similar to that of non-encysted animal cuticles, while in D. parthenogeneticus the ultrastructure of the new cuticular involucra differs from that of non-encysted animal cuticle. A modified buccal-pharyngeal apparatus has been observed both in “type 2” cyst of A. volubilis and in the D. parthenogeneticus cyst. [ABSTRACT FROM AUTHOR]

It is not rare to find in references that anhydrobiotic tardigrades can survive for more than a century. However, a closer look at the empirical evidence provides very little support that tardigrades are capable of surviving dried for such a long time. In order to resolve this discrepancy, we carried out a study to evaluate the long-term survival of naturally dried tardigrades. A large fragment of dry lichen ( Xanthoria parietina) was collected in the field two days after a rainy day in 1999. The dry lichen was stored inside a paper bag in the laboratory at room temperature and humidity and under atmospheric oxygen exposure. Replicates of the dry lichen were re-hydrated after various time periods of storage, with all tardigrades extracted and the survivors enumerated. Five species of tardigrades were found, but two of them only occasionally. Ramazzottius oberhaeuseri, Echiniscus testudo and Echiniscus trisetosus were sufficiently represented for statistical analysis. At the beginning of the experiment 91.1% of R. oberhaeuseri and 71.7% of Echiniscus spp. were alive. R. oberhaeuseri survived up to 1604 days, while Echiniscus spp. lived up to 1085 days. Recovery after four years of anhydrobiosis has to be considered a very good long-term survival, which is important from an ecological and evolutionary point of view. [ABSTRACT FROM AUTHOR]

Guidetti, R., Gandolfi, A., Rossi, V.&Bertolani, R. (2005). Phylogenetic analysis of Macrobiotidae (Eutardigrada, Parachela): a combined morphological and molecular approach.— Zoologica Scripta, **, ***–***.Combined analyses of morphological and molecular data were used to resolve phylogenetic relationships within Macrobiotidae (Eutardigrada). Morphological data were analysed using a cladistic approach with a matrix comprising 15 taxa with 17 characters to obtain a phylogenetic reconstruction. Molecular data were obtained by sequencing the cytochromecoxidase subunit I gene in seven species of Macrobiotidae and one of Eohypsibiidae (used as outgroup). The morphological character defining the family, symmetrical claw on each leg, turns out to be plesiomorphic. Moreover, neither morphological nor molecular analyses supports a monophyletic clade for the subfamily Macrobiotinae, whereas both support a well defined evolutionary line (Murrayinae) within the family. We propose elevating the latter to family level (Murrayidae) while temporarily retaining as valid the family Macrobiotidae (amending its diagnosis, including within it only Macrobiotinae). Murrayidae opens an interesting evolutionary prospective, because the entire line has differentiated without sexual reproduction, constituting an example of evolution of asexual lineages. [ABSTRACT FROM AUTHOR]

The existence of a group of species similar to Diphascon (Diphascon) nobilei is shown. These species have some common characteristics: a well-evident drop-shaped thickening between the buccal tube and the pharyngeal tube, pharyngeal bulb, more or less elongate, with three rod-shaped macroplacoids and microplacoid, claws of the hind legs different from those of the first three pairs of legs in having a very wide basal portion and indented basal margin, basal spurs also present on the external claws and, in some cases, also on the internal claws of the first three pairs of legs. Four new species of this group are described: Diphascon (D.) serratum , D. (D.) nelsonae , D. (D.) platyungue , and D. (D.) hydrophilum . They differ from one another in the dimensions and shape of the claws; in some cases the difference also affects the value of the ptd index relative to the insertion point of the stylet supports, the buccal and the pharyngeal tube length or the macroplacoid length. [ABSTRACT FROM AUTHOR]

Presents a study which assessed the breeding system of different populations of eutardigrade Richtersius coronifer. Karyological analyses; Evaluation of sex-ratios; Genetic structure using allozyme markers; Deviation from Hardy-Weinberg equilibrium of genotype frequencies.

This work represents the first attempt to define tardigrade chromosomes using banding techniques. Macrobiotus richtersi, a eutardigrade morphospecies with amphimictic diploid and thelytokous triploid cytotypes, was used as a model. Prime consideration was given to oocyte chromosomes because they are larger than those of spermatocytes and of mitotic chromosomes. With Giemsa staining, the chromatids of the 6 bivalents of the diploid cytotypes and those of the 17–18 univalents of the triploid cytotypes were very similar to each other and appeared rod- or flame-shaped. In the amphimictic strain, a chiasma was generally present in each bivalent at diplotene, whereas there were no chiasmata in the oocyte prophase chromosomes of the triploid strain. Both in diploid and triploid cytotypes, C-banding and fluorescence showed a heterochromatic centromeric band on the telomere of each chromosome oriented towards the spindle pole, indicating that all of them were acrocentric. Silver staining showed the presence of a NOR in only a pair of chromosomes, close to the centromeric C-banded site. NOR was particularly evident in the oocyte prophases. Other silver positive regions, corresponding to the kinetochore, were located on all other chromosomes on the telomeres towards the spindle pole. [ABSTRACT FROM AUTHOR]

The cuticle of tardigrades is characterized by three main layers: epicuticle, intracuticle and procuticle. Pillars are present in the epicuticle of almost all heterotardigrades, but these structures are also known in a few species of eutardigrades. The apparent heterogeneity of the cuticular ultrastructure in several species of the Macrobiotidae (Eutardigrada) prompted us to analyse the structure of the cuticle in this family. Eleven species in several genera were investigated with light and/or electron microscopy. All the species of the genera Murrayon and Dactylobiotus showed pillars in the epicuticle, whereas the examined species of Macrobiotus, Richtersius and Xerobiotus completely lacked pillars. Therefore, in the Macrobiotidae, in contrast to what appears with light microscopy, the cuticle is homogeneous within each genus examined at the electron microscopic level. Considering the absence of pillars in the Macrobiotidae a synapomorphy, we propose the erection of two new subfamilies. Macrobiotinae subfam. n. is characterized by the absence of pillars in the epicuticular layer and includes, in addition to the genera Macrobiotus, Xerobiotus and Richtersius, the genera Pseudohexapodibius, Adorybiotus, and probably also Minibiotus, Calcarobiotus and Pseudodiphascon. Murrayinae subfam. n. is characterized by the presence of pillars in the epicuticular layer and includes the genera Murrayon, Dactylobiotus and, probably, Macroversum. [ABSTRACT FROM AUTHOR]

For many years, Paramacrobiotus richtersi was reported to consist of populations with different chromosome numbers and reproductive modes. To clarify the relationships among different populations, the type locality of the species (Clare Island, Ireland) and several Italian localities were sampled. Populations were investigated with an integrated approach, using morphological (LM, CLSM, SEM), morphometric, karyological, and molecular (18S rRNA, cox1 genes) data. Paramacrobiotus richtersi was redescribed and a neotype designed from the Irish bisexual population. Animals of all populations had very similar qualitative and quantitative characters, apart from the absence of males and the presence of triploidy in some of them, whereas some differences were recorded in the egg shell. All populations examined had the same 18S haplotype, while 21 haplotypes were found in the cox1 gene. In four cases, those qualitative characters were correlated with clear molecular (cox1) differences (genetic distance 14.6–21.8%). The integrative approach, which considered the morphological differences in the eggs, the reproductive biology and the wide genetic distances among putative species, led to the description of four new species (Paramacrobiotus arduus sp. n., Paramacrobiotus celsus sp. n., Paramacrobiotus depressus sp. n., Paramacrobiotus spatialis sp. n.) and two Unconfirmed Candidate Species (UCS) within the P. richtersi complex. Paramacrobiotus fairbanksi, the only ascertained parthenogenetic, triploid species, was redescribed and showed a wide distribution (Italy, Spain, Poland, Alaska), while the amphimictic species showed limited distributions. The difference in distribution between apomictic and amphimictic populations can be explained by the difference in the dispersal potentials associated with these two types of reproduction. [ABSTRACT FROM AUTHOR]

The article announces the Tenth International Symposium on Tardigrada that will be held on June 18-23, 2006 in Catania, Italy. It includes information on the organizing committee, issues that will be addressed, and the availability of tardigrade collections.