Integrative description of Macrobiotus canaricus sp. nov. with notes on M. recens (Eutardigrada : Macrobiotidae)

In this paper we describe Macrobiotus canaricus sp. nov., a new tardigrade species of the Macrobiotus hufelandi group from the Canary Islands. Moreover, with the use of DNA sequencing, we confirm that Macrobiotus recens Cuénot, 1932 represents the hufelandi group, even though eggs laid by this species do not exhibit the typical hufelandi group morphology. Our study is based on both classical taxonomic methods that include morphological and morphometric analyses conducted with the use of light and scanning electron microscopy, and on the analysis of nucleotide sequences of four molecular markers (three nuclear: 18S rRNA, 28S rRNA, ITS-2, and one mitochondrial: COI). Our analyses revealed that M. canaricus sp. nov. is most similar to Macrobiotus almadai Fontoura et al., 2008 from the Archipelago of the Azores, from which it differs by the absence of granulation patches on the external and internal surfaces of legs I–III as well as by the absence of a cuticular pore in the centre of the external patch on legs I–III. Molecular sequences allowed us to pinpoint the phylogenetic positions of M. canaricus sp. nov. and M. recens within the M. hufelandi group

An integrative description of a population of Mesobiotus radiatus (Pilato, Binda & Catanzaro, 1991) from Kenya

In a moss sample collected from Mount Kulal in Kenya, a new population of Mesobiotus radiatus was found. Given that the original description of M. radiatus was based solely on the morphology observed by light microscopy and measurements based mostly on a single individual, here we describe the new population by means of integrative taxonomy and a large sample size. We provide an integrative description comprising a comprehensive set of morphometric and morphological data from light and scanning microscopy as well as nucleotide sequences of three nuclear fragments (18S rRNA, 28S rRNA, ITS-2) and one mitochondrial fragment (COI). Mesobiotus radiatus is most similar to M. binieki, M. coronatus, M. patiens, M. perfidus, M. philippinicus, M. pseudocoronatus, M. pseudopatiens, M. rigidus, M. simulans, and M. wuzhishanensis, but differs from them mainly by egg morphology and morphometry, and some characters of adult specimens

The first record of Macrobiotus vladimiri Bertolani, Biserov, Rebecchi & Cesari, 2011 (Tardigrada : Eutardigrada : Macrobiotidae : hufelandi group) from Poland

Tardigrade studies in Poland have been carried out for more than a century and to date, 102 species have been reported from this central European country. This constitutes nearly 9% of all known species within the phylum. Although previous studies have been thorough, a number of taxa now known to belong to species complexes have been treated in only a very general way. One such complex is the Macrobiotus hufelandi group, which has a worldwide distribution. To date, only three hufelandi group species have been recorded from Poland: M. hufelandi hufelandi C.A.S. Schultze, 1834; M. macrocalix Bertolani & Rebecchi, 1993; and M. polonicus Pilato, Kaczmarek, Michalczyk & Lisi, 2003. Here we first report M. vladimiri Bertolani, Biserov, Rebecchi & Cesari, 2011 from Poland. Moreover, we provide new morphometric data for the type series of the species

An integrative description of a new Richtersius species from Greece (Tardigrada: Eutardigrada: Richtersiusidae)

In this paper, we describe a new tardigrade species, Richtersius tertius sp. n., from Greece. The description is based on morphological and morphometric analysis using light and scanning electron microscopy as well as genetic analysis based on four molecular markers (DNA sequences of three nuclear, i.e., 18S rRNA, 28S rRNA, ITS-2 and one mitochondrial COI fragment). Morphological and morphometric differences, together with genetic comparisons, provide independent verifications of Richtersius tertius sp. n. as a species new to science. Phenotypically, the new taxon differs from Richtersius coronifer (Richters, 1903) and Richtersius ziemowiti Kayastha, Berdi, Miaduchowska, Gawlak, Łukasiewicz, Gołdyn, Jędrzejewski et Kaczmarek, 2020 mainly by the morphology and size of cuticular pores, present only in hatchlings (first instars), as well as some morphometric characters. The results presented herein contribute further to the recognition of the morphological variability and biodiversity within Richtersius, with Richtersius tertius sp. n. being the third species formally described within the genus

An integrative description of Mesobiotus ethiopicus sp. nov. (Tardigrada : Eutardigrada : Parachela : Macrobiotidae : harmsworthi group) from the northern Afrotropic region

A new species of the Mesobiotus harmsworthi group is described from Ethiopia. An integrative taxonomy approach was applied by combining morphological and morphometric analyses-imaging under phase contrast and scanning electron microscopy with molecular analysis (18S rRNA, 28S rRNA and COI markers)-to cross-verify the status of the population as a new species. The specimens of esobiotus ethiopicus sp. nov. are most similar to two taxa of the harmsworthi complex: M. harmsworthi obscurus (Dastych, 1985) and M. peterseni (Maucci, 1991). Nevertheless, the new species can be easily distinguished from the first of these taxa by the absence of additional teeth in the oral cavity and by a different accessory point morphology on the claws, and it can be distinguished from the second species mostly by a completely different egg process anatomy. Mesobiotus ethiopicus sp. nov. is only the second tardigrade species formally described as new for science from Ethiopia so far

An integrative description of Minibiotus ioculator sp. nov. from the Republic of South Africa with notes on Minibiotus pentannulatus Londoño et al., 2017 (Tardigrada: Macrobiotidae)

The genusMinibiotusis morphologically diverse, which may suggest its polyphyletic character. However,scarce genetic data and often also the lack of detailed morphological data currently do not allow for theverification of the relationships within this genus. Here, for the veryfirst time, we provide an integrativedescription of a newMinibiotusspecies.Minibiotus ioculatorsp. nov.from the Republic of South Africadiffers from other congeners mainly by egg ornamentation with processes on the egg shell that resemblethe hat of a royal jester. We also provide new taxonomic data onMinibiotus pentannulatusbased on apopulation newly found in Tanzania, which constitutes thefirst African record of this species originallydescribed from South America. Our study involved both classical taxonomic methods, which includemorphological and morphometric analyses conducted with the use of light and scanning electron mi-croscopy, and genetic data in the form of DNA sequences of four markers (three nuclear: 18S rRNA, 28SrRNA, ITS-2, and one mitochondrial: COI). The results of this study allow a discussion of speciescomposition withinMinibiotusand question the validity of the current diagnosis of the genus

Deceptive conservatism of claws : distinct phyletic lineages concealed within Isohypsibioidea (Eutardigrada) revealed by molecular and morphological evidence

Isohypsibioidea are most likely the most basally branching evolutionary lineage of eutardigrades. Despite being second largest eutardigrade order, phylogenetic relationships and systematics within this group remain largely unresolved. Broad taxon sampling, especially within one of the most speciose tardigrade genera, Isohypsibius Thulin, 1928, and application of both comparative morphological methods (light contrast and scanning electron microscopy imaging of external morphology and buccal apparatuses) and phylogenetic framework (18S + 28S rRNA sequences) resulted in the most comprehensive study devoted to this order so far. Two new families are erected from the currently recognised family Isohypsibiidae: Doryphoribiidae fam. nov., comprising all aquatic isohypsibioids and some terrestrial isohypsibioid taxa equipped with the ventral lamina; and Halobiotidae fam. nov., secondarily marine eutardigrades with unique adaptations to sea environment. We also split Isohypsibius into four genera to accommodate phylogenetic, morphological and ecological variation within the genus: terrestrial Isohypsibius s.s. (Isohypsibiidae), with smooth or sculptured cuticle but without gibbosities; terrestrial Dianea gen. nov. (Isohypsibiidae), with small and pointy gibbosities; terrestrial Ursulinius gen. nov. (Isohypsibiidae), with large and rounded gibbosities; and aquatic Grevenius gen. nov. (Doryphoribiidae fam. nov.), typically with rough cuticle and claws with branches of very similar heigths. Claw morphology is reviewed and, for the first time, shown to encompass a number of morphotypes that correlate with clades recovered in the molecular analysis. The anatomy of pharynx and cuticle are also shown to be of high value in distinguishing supraspecific taxa in Isohypsibioidea. Taxonomy of all isohypsibioid families and genera is discussed, with special emphasis on the newly erected entities. Finally, a dychotomous diagnostic key to all currently recognised isohypsibioid families and genera is provided

Integrative taxonomy identifies two new tardigrade species (Eutardigrada: Macrobiotidae) from Greenland

In this paper we describe Macrobiotus engbergi sp. nov. and Tenuibiotus zandrae sp. nov. from Greenland. Our study has involved both classical taxonomic methods, which include morphological and morphometric analyses conducted with the use of light and scanning electron microscopy, and genetic analysis based on four molecular markers (three nuclear: 18S rRNA, 28S rRNA, ITS-2, and one mitochondrial: COI). Moreover, we re-examined the type series of Tenuibiotus voronkovi (Tumanov, 2007) as well as the original sample where the species was found and we provide new morphological data from light and scanning electron microscopy which enabled us to amend its description. Finally, we also analysed slides with animals and egg of two populations from Nordaustlandet and Edgeøya (archipelago of Svalbard, Norway) designated as T. voronkovi within its recent redescription. The results and comparisons presented in our study question the validity of this designation.

Integrative redescription of a common Arctic water bear Pilatobius recamieri (Richters, 1911)

Tardigrada are a group of microscopic metazoans that inhabit a variety of ecosystems throughout the world, including polar regions, where they are a constant element of microfauna with densities exceeding hundreds of individuals per gram of dry plant material. However, despite a long history of research and their ubiquity in tundra ecosystems, the majority of tardigrade species have limited and outdated diagnoses. One such example is Pilatobius recamieri, a common tardigrade that is widely distributed in the Arctic. The aim of this study is to redescribe this species using new material from the type locality and tools of integrative taxonomy, viz. by combining classical imaging and morphometry by light microscopy and scanning electron microscopy imaging with DNA sequencing of four markers with various mutation rates: three nuclear (18S rRNA, 28S rRNA, and ITS-2) and one mitochondrial (COI). The sequences of the three latter markers are also the first to be presented for the genus Pilatobius. This study therefore provides the first necessary step towards the verification of the geographic range of P. recamieri, which is currently assumed to be very broad. A detailed comparison of P. recamieri with Pilatobius secchii (Bertolani and Rebecchi, 1996) from Italy revealed no morphological or morphometric differences between the two species, thus we designate P. secchii as a nomen inquirendum until molecular data for the taxon become available. Finally, we propose to replace the term "lunula" in the superfamilies Hypsibioidea and Isohypsibioidea with the more appropriate "pseudolunula" to differentiate it from the true lunula in other parachelans