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Gsiorek P, Vonina K. Atlas of the Echiniscidae (Heterotardigrada) of the Worldpart I: West Palaearctic Echiniscus species. Zootaxa 2023; 5344:1-72. [PMID: 38221356 DOI: 10.11646/zootaxa.5344.1.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Indexed: 01/16/2024]
Abstract
Traditionally Eurocentric tardigrade taxonomy has started to dissect endemics from very few truly cosmopolitan or widely distributed species, originally described mostly from the West Palaearctic, in the last decade. Obviously, the most problematic for taxonomic identification are species in large genera containing over 100 species in the case of Tardigrada. In limno-terrestrial heterotardigrades, only Echiniscus C.A.S. Schultze, 1840 fulfils this criterion, being a perfect example of taxonomic inflation. In Echiniscidae, this phenomenon results predominantly from the historical fallacy of attaching more importance to chaetotaxy than to the analysis of dorsal plate sculpturing. In this paper, the first of a series on echiniscids of the World, we review the current state of knowledge on the West Palaearctic Echiniscus species. Echiniscus granulatus (Doyre, 1840) and E. spinulosus (Doyre, 1840) are re-described based on multiple population data. Echiniscus lapponicus Thulin, 1911 and E. militaris Murray, 1911 are provided with the first SEM and molecular data, respectively. Following synonymies are made based on analyses of ample comparative material, type series, and redescriptions: E. blumi schizofilus Barto, 1941 syn. nov. and E. trojanus Maucci, 1973 syn. nov. of E. blumi blumi Richters, 1903; E. inocelatus Miheli, 1938 syn. nov., E. heterospinosus Maucci, 1954 syn. nov. and E. egnatiae Durante Pasa & Maucci, 1979 syn. nov. of E. granulatus; Echiniscus merokensis suecicus Thulin, 1911 syn. nov., E. columinis Murray, 1911 syn. nov., E. batramiae Iharos, 1936 syn. nov., E. jagodici Miheli, 1951 syn. nov. and E. laterospinosus Rudescu, 1964 syn. nov. of E. merokensis merokensis Richters, 1904; E. hexacanthus Maucci, 1973 syn. nov. of E. militaris Murray, 1911; E. carusoi Pilato, 1972 syn. nov. of E. spinulosus; E. osellai Maucci, 1974 syn. nov. of E. trisetosus Cunot, 1932. Two new nomina dubia are proposed: E. apuanus M. Bertolani, 1946 sp. dub. (and a probable synonymy with E. merokensis suggested) and E. pajstunensis Barto, 1941 sp. dub. Two new nomina inquirenda are established: E. marleyi Li, 2007 sp. inq. (another chaetotaxy-based morphotype of the Echiniscus blumi-canadensis complex) and E. punctus McInnes, 1995 sp. inq. (the lack of reliable morphological criteria separating it from E. granulatus). We summarise the morphological, phylogenetic and biogeographic information for the West Palaearctic Echiniscus species, and conclude with a total of 21 valid and identifiable taxa. We predict this number will decrease further with solving the species delimitation issues within the Echiniscus blumi-canadensis complex. Among these 21 taxa, 13 species (62%) are to be found solely in the Western Palaearctic and/or entire Holarctic regions. This augments the many recent findings that tardigrades are typically biogeographically structured and form clearly defined faunae.
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Affiliation(s)
- Piotr Gsiorek
- Department of Invertebrate Evolution; Faculty of Biology; Jagiellonian University; Gronostajowa 9; 30-387 Krakw; Poland; Natural History Museum of Denmark; University of Copenhagen; ster Voldgade 5-7; DK-1350; Universitetsparken 15; DK-2100; Copenhagen; Denmark.
| | - Katarzyna Vonina
- Senckenberg Research Institute and Natural History Museum Frankfurt; Senckenberganlage 25; 60325 Frankfurt am Main; Germany.
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Gąsiorek P. Eventually tested: Phylogenetic position of “Testechiniscus” meridionalis (Murray, 1906) (Heterotardigrada) revealed. ZOOL ANZ 2023. [DOI: 10.1016/j.jcz.2023.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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3
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Suzuki AC, Sugiura K, Tsujimoto M, Nakai R, McInnes SJ, Kagoshima H, Imura S. A New Species of Bisexual Milnesium (Eutardigrada: Apochela) Having Aberrant Claws from Innhovde, Dronning Maud Land, East Antarctica. Zoolog Sci 2023; 40:246-261. [DOI: 10.2108/zs220085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 11/30/2022] [Indexed: 02/04/2023]
Affiliation(s)
- Atsushi C. Suzuki
- Department of Biology, Keio University, 4-1-1 Hiyoshi, Yokohama 223-8521, Japan
| | - Kenta Sugiura
- Department of Biosciences and Bioinformatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522, Japan
| | - Megumu Tsujimoto
- Faculty of Environment and Information Studies, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan
| | - Ryosuke Nakai
- National Institute of Advanced Industrial Science and Technology, 2-17-2-1 Tsukisamu-Higashi, Sapporo 062-0052, Japan
| | - Sandra J. McInnes
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | | | - Satoshi Imura
- National Institute of Polar Research, 10-3 Midori-cho, Tachikawa, Tokyo 190-8518, Japan
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Integrative taxonomy helps to revise systematics and questions the purported cosmopolitan nature of the type species within the genus Diaforobiotus (Eutardigrada: Richtersiusidae). ORG DIVERS EVOL 2022. [DOI: 10.1007/s13127-022-00592-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Recent advances in tardigrade taxonomy have been greatly enhanced by the redescriptions of the type species for particular taxa or species groups. De novo characterisation of these key taxa now allows to describe tardigrade species diversity with improved precision and at higher rate, increasing the momentum towards resolving the taxonomic impediment in these micro-invertebrates. Since its description, Diaforobiotus islandicus (Richters, 1904) has been reported from many distinct localities around the world. This suggested, perhaps falsely, a cosmopolitan nature of the species. However, potential erroneous assignment of newly found populations to this species could be a result of the very general and superficial original description. In order to properly recognise and name species diversity within the genus, I provide here an integrative redescription of the type species (D. islandicus) with a neotype designation, a description of a new species, Diaforbiotus svalbardicus sp. nov, and dichotomous key for the genus. Both descriptions are based on detailed morphological and morphometric data associated with standard DNA sequences of four genetic markers (18S rRNA, 28S rRNA, ITS-2, and COI). The genus composition and diagnosis amendments of the family Richtersiuside are also discussed. The presented study constitutes a starting point for further systematic studies on the genus Diaforobiotus and new taxa discoveries.
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Gąsiorek P. Water bear with barbels of a catfish: A new Asian Cornechiniscus (Heterotardigrada: Echiniscidae) illuminates evolution of the genus. ZOOL ANZ 2022. [DOI: 10.1016/j.jcz.2022.06.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Bartylak T, Kayastha P, Roszkowska M, Kepel A, Kepel M, Kaczmarek Ł. Tardigrades of the Ivohibory forest (south-central Madagascar) with a description of a new Bryodelphax species. THE EUROPEAN ZOOLOGICAL JOURNAL 2022. [DOI: 10.1080/24750263.2022.2042404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- T. Bartylak
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poznań, Poland
| | - P. Kayastha
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poznań, Poland
| | - M. Roszkowska
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poznań, Poland
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University in Poznań, Poznań
| | - A. Kepel
- Polish Society for Nature Conservation “Salamandra”, Poznań, Poland
| | - M. Kepel
- Polish Society for Nature Conservation “Salamandra”, Poznań, Poland
| | - Ł. Kaczmarek
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poznań, Poland
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An ancient, Antarctic-specific species complex: large divergences between multiple Antarctic lineages of the tardigrade genus Mesobiotus. Mol Phylogenet Evol 2022; 170:107429. [DOI: 10.1016/j.ympev.2022.107429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 11/21/2022]
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Azambuja M, Marcondes DS, Nogaroto V, Moreira-Filho O, Vicari MR. Population structuration and chromosomal features homogeneity in Parodon nasus (Characiformes: Parodontidae): A comparison between Lower and Upper Paraná River representatives. NEOTROPICAL ICHTHYOLOGY 2022. [DOI: 10.1590/1982-0224-2021-0162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ABSTRACT The ichthyofauna of the La Plata hydrographic basin is divided into Upper and Lower Paraná River systems due to the geographic isolation of the Sete Quedas waterfalls, currently flooded by the lake of the Itaipu dam. In Parodontidae, pairs of species, or groups of cryptic species were described between these systems. Although genetic isolation and speciation have already been proposed in other species in the group, Parodon nasus has been maintained as a valid species and distributed throughout the La Plata river basin. In this perspective, specimens of P. nasus from four different sampling sites in the Upper and Lower Paraná River systems were compared regarding the karyotypes, molecular analyzes of population biology and species delimitation to investigate their genetic and population isolation in the La Plata river basin. Despite a geographic barrier and the immense geographic distance separating the specimens sampled from the Lower Paraná River system compared to those from the Upper Paraná River, the data obtained showed P. nasus as a unique taxon. Thus, unlike other species of Parodontidae that showed diversification when comparing the groups residing in the Lower versus Upper Paraná River, P. nasus showed a population structure and a karyotypic homogeneity.
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Phenotypically exceptional Echiniscus species (Heterotardigrada: Echiniscidae) from Argentina (Neotropics). ZOOL ANZ 2021. [DOI: 10.1016/j.jcz.2021.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Gross V, Epple L, Mayer G. Organization of the central nervous system and innervation of cephalic sensory structures in the water bear Echiniscus testudo (Tardigrada: Heterotardigrada) revisited. J Morphol 2021; 282:1298-1312. [PMID: 34129245 DOI: 10.1002/jmor.21386] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/22/2021] [Accepted: 06/13/2021] [Indexed: 11/09/2022]
Abstract
The tardigrade brain has been the topic of several neuroanatomical studies, as it is key to understanding the evolution of the central nervous systems in Panarthropoda (Tardigrada + Onychophora + Arthropoda). The gross morphology of the brain seems to be well conserved across tardigrades despite often disparate morphologies of their heads and cephalic sensory structures. As such, the general shape of the brain and its major connections to the rest of the central nervous system have been mapped out already by early tardigradologists. Despite subsequent investigations primarily based on transmission electron microscopy or immunohistochemistry, characterization of the different regions of the tardigrade brain has progressed relatively slowly and open questions remain. In an attempt to improve our understanding of different brain regions, we reinvestigated the central nervous system of the heterotardigrade Echiniscus testudo using anti-synapsin and anti-acetylated α-tubulin immunohistochemistry in order to visualize the number and position of tracts, commissures, and neuropils. Our data revealed five major synapsin-immunoreactive domains along the body: a large unitary, horseshoe-shaped neuropil in the head and four neuropils in the trunk ganglia, supporting the hypothesis that the dorsal brain is serially homologous with the ventral trunk ganglia. At the same time, the pattern of anti-synapsin and anti-tubulin immunoreactivity differs between the ganglia, adding to the existing evidence that each of the four trunk ganglia is unique in its morphology. Anti-tubulin labeling further revealed two commissures within the central brain neuropil, one of which is forked, and additional sets of extracerebral cephalic commissures associated with the stomodeal nervous system and the ventral cell cluster. Furthermore, our results showing the innervation of each of the cephalic sensilla in E. testudo support the homology of subsets of these structures with the sensory fields of eutardigrades.
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Affiliation(s)
- Vladimir Gross
- Department of Zoology, Institute of Biology, University of Kassel, Kassel, Germany
| | - Lisa Epple
- Department of Zoology, Institute of Biology, University of Kassel, Kassel, Germany
| | - Georg Mayer
- Department of Zoology, Institute of Biology, University of Kassel, Kassel, Germany
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Kiosya Y, Vončina K, Gąsiorek P. Echiniscidae in the Mascarenes: the wonders of Mauritius. EVOLUTIONARY SYSTEMATICS 2021. [DOI: 10.3897/evolsyst.5.59997] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Many regions of the world remain unexplored in terms of the tardigrade diversity, and the islands of the Indian Ocean are no exception. In this work, we report four species of the family Echiniscidae representing three genera from Mauritius, the second largest island in the Mascarene Archipelago. Two species belong in the genus Echiniscus: Echiniscus perarmatus Murray, 1907, a pantropical species, and one new species: Echiniscus insularissp. nov., one of the smallest members of the spinulosus group and the entire genus, being particularly interesting due to the presence of males and supernumerary teeth-like spicules along the margins of the dorsal plates. The new species most closely resembles Echiniscus tropicalis Binda & Pilato, 1995, for which we present extensive multipopulation data and greatly extend its distribution eastwards towards islands of Southeast Asia. Pseudechiniscus (Meridioniscus) mascarenensissp. nov. is a typical member of the subgenus with elongated (dactyloid) cephalic papillae and the pseudosegmental plate IV’ with reduced posterior projections in males. Finally, a Bryodelphax specimen is also recorded. The assemblage of both presumably endemic and widely distributed tardigrade species in Mauritius fits the recent emerging biogeographic patterns for this group of micrometazoans.
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12
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Fleming JF, Arakawa K. Systematics of tardigrada: A reanalysis of tardigrade taxonomy with specific reference to Guil et al. (2019). ZOOL SCR 2021. [DOI: 10.1111/zsc.12476] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James F. Fleming
- Keio University Institute for Advanced Tsuruoka Japan
- University of Oslo Natural History Museum Oslo Norway
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13
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Gąsiorek P, Oczkowski A, Blagden B, Kristensen RM, Bartels PJ, Nelson DR, Suzuki AC, Michalczyk Ł. New Asian and Nearctic Hypechiniscus species (Heterotardigrada: Echiniscidae) signalize a pseudocryptic horn of plenty. Zool J Linn Soc 2020. [DOI: 10.1093/zoolinnean/zlaa110] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
The cosmopolitan echiniscid genus Hypechiniscus contains exclusively rare species. In this contribution, by combining statistical morphometry and molecular phylogeny, we present qualitative and quantitative aspects of Hypechiniscus diversity, which remained hidden under the two purportedly cosmopolitan species: H. gladiator and H. exarmatus. A neotype is designated for H. gladiator from Creag Meagaidh (Scotland), and an informal re-description is provided for H. exarmatus based on animals from Creag Meagaidh and the Isle of Skye (Inner Hebrides). Subspecies/forms of H. gladiator are suppressed due to the high developmental variability of the cirrus dorsalis. At the same time, four species of the genus are described: H. daedalus sp. nov. from Roan Mountain and the Great Smoky Mountains (Southern Appalachian Mountains, USA), H. flavus sp. nov. and H. geminus sp. nov. from the Yatsugatake Mountains (Honshu, Japan), and H. cataractus sp. nov. from the Malay Archipelago (Borneo and the Moluccas). Dorsal and ventral sculpturing, together with morphometric traits, are shown to be the key characters that allow for the phenotypic discrimination of species within the genus. Furthermore, the morphology of Hypechiniscus is discussed and compared to that of the most similar genera, Pseudechiniscus and Stellariscus. Finally, a diagnostic key to all recognized Hypechiniscus species is provided.
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Affiliation(s)
- Piotr Gąsiorek
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa, Kraków, Poland
| | - Artur Oczkowski
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa, Kraków, Poland
| | - Brian Blagden
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa, Kraków, Poland
| | - Reinhardt M Kristensen
- Natural History Museum of Denmark, University of Copenhagen, Universitetsparken, Copenhagen Ø, Denmark
| | - Paul J Bartels
- Department of Biology, Warren Wilson College, Asheville, NC, USA
| | - Diane R Nelson
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, USA
| | | | - Łukasz Michalczyk
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa, Kraków, Poland
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Stec D, Vecchi M, Maciejowski W, Michalczyk Ł. Resolving the systematics of Richtersiidae by multilocus phylogeny and an integrative redescription of the nominal species for the genus Crenubiotus (Tardigrada). Sci Rep 2020; 10:19418. [PMID: 33173036 PMCID: PMC7655870 DOI: 10.1038/s41598-020-75962-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/22/2020] [Indexed: 11/27/2022] Open
Abstract
The family Richtersiidae, although established recently with the use of phylogenetic methods, was considered potentially paraphyletic at the time of its erection. Until now, the family comprised four genera, Richtersius, Diaforobiotus, Adorybiotus and a newly erected genus Crenubiotus. However, the genetic characterisation for the latter two genera was very limited or absent. To address concerns about the phylogenetic affinity of these two genera, we present a multilocus phylogeny of the families Richtersiidae and Murrayidae based on four molecular markers (18S rRNA, 28S rRNA, ITS-2 and COI). Our results show a distinct evolutionary lineage composed of Adorybiotus and Crenubiotus, which is sister to Murrayidae. In order to accommodate the phylogenetic and morphological distinctiveness of this lineage, we erect a new family, Adorybiotidae fam. nov. The new taxon differs morphologically from other families in the superfamily Macrobiotoidea by a unique combination of traits: (1) the presence of tubercles/cushions with aggregations of microgranules on their surfaces present on all legs and on the dorso-caudal cuticle, (2) a system of internal septa in claws, and (3) buccal apparatus morphology. Moreover, in order to stabilise the taxonomy and nomenclature in the genus Crenubiotus, we redescribe its type species, Crenubiotus crenulatus, by means of integrative taxonomy and designate a new neotype based on a population from the original terra typica.
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Affiliation(s)
- Daniel Stec
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland.
| | - Matteo Vecchi
- Department of Biological and Environmental Science, University of Jyvaskyla, PO Box 35, Jyvaskyla, 40014, Finland
| | - Wojciech Maciejowski
- Institute of the Middle and Far East, Jagiellonian University, Oleandry 2a, 30-063, Kraków, Poland
| | - Łukasz Michalczyk
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland.
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Sugiura K, Minato H, Matsumoto M, Suzuki AC. Milnesium (Tardigrada: Apochela) in Japan: The First Confirmed Record of Milnesium tardigradum s.s. and Description of Milnesium pacificum sp. nov. Zoolog Sci 2020; 37:476-495. [PMID: 32972089 DOI: 10.2108/zs190154] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/31/2020] [Indexed: 11/17/2022]
Abstract
Presently, more than 40 species of the genus Milnesium Doyère, 1840 (Tardigrada: Eutardigrada: Apochela: Milnesiidae) have been described. In Japan, however, almost all records of milnesiid tardigrades should be re-examined with the current criteria on the taxonomy of this genus, except for one species, the recently described Milnesium inceptum Morek, Suzuki, Schill, Georgiev, Yankova, Marley, and Michalczyk, 2019. In this study, we found two species, Milnesium pacificum sp. nov. and Milnesium tardigradum Doyère, 1840, from three southern islands and two cold regions in Japan, respectively. Milnesium pacificum sp. nov., having dorsal sculpturing, exhibits an early positive change in claw configuration. On the other hand, M. tardigradum s.s. from Japan has an early negative claw configuration change, as has been reported in a recent study on the neotype population of this species. We performed DNA barcoding for both species, which indicated that M. pacificum sp. nov. has a close affinity with an undescribed Milnesium species collected from Brazil, and that M. tardigradum from Japan represents the recently described subclade that contains specimens from Poland, Hungary, and Russia. The chromosome numbers were 2n = 14 in M. pacificum sp. nov. and 2n = 10 in M. tardigradum. We detected at least three species of the genus Milnesium present in Japan. Our results advance the investigation of the relationship between phylogenetic position and characteristic morphology as well as expand the known geographic range of M. tardigradum.
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Affiliation(s)
- Kenta Sugiura
- School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Hiyoshi, Yokohama 223-8522, Japan
| | - Hiroki Minato
- School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Hiyoshi, Yokohama 223-8522, Japan
| | - Midori Matsumoto
- School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Hiyoshi, Yokohama 223-8522, Japan
| | - Atsushi C Suzuki
- Department of Biology, School of Medicine, Keio University, Hiyoshi, Yokohama 223-8521, Japan,
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Vončina K, Kristensen RM, Gąsiorek P. Pseudechiniscus in Japan: re-description of Pseudechiniscus asper Abe et al., 1998 and description of Pseudechiniscus shintai sp. nov. ZOOSYST EVOL 2020. [DOI: 10.3897/zse.96.53324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The classification and identification of species within the genus Pseudechiniscus Thulin, 1911 has been considered almost a Sisyphean work due to an extremely high homogeneity of its members. Only recently have several contributions made progress in the taxonomy feasible through their detailed analyses of morphology and, crucially, by the re-description of the ancient, nominal species P. suillus (Ehrenberg, 1853). Herein, we focus on the Japanese representatives of this genus: P. asper, a rare species originally described from Hokkaido, and a new species P. shintai. Both taxa belong to the widespread suillus-facettalis complex. Detailed descriptions entailing DNA barcoding of four markers and illustrations of the ventral pillar patterns are indispensable for an accurate delineation of species within this genus.
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Gąsiorek P, Michalczyk Ł. Revised Cornechiniscus (Heterotardigrada) and new phylogenetic analyses negate echiniscid subfamilies and tribes. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200581. [PMID: 32742698 PMCID: PMC7353990 DOI: 10.1098/rsos.200581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
Abstract
Echiniscidae are undoubtedly the most thoroughly studied lineage of the class Heterotardigrada. Recently, new subfamilies and tribes grouping echiniscid genera based on traditionally recognized morphological clues have been proposed. Here, by integrative analyses of morphology and DNA sequences of numerous populations of a rare genus Cornechiniscus, we show that this hypothesized classification is artificial. Specifically, we demonstrate that Echiniscinae are diphyletic, as Bryodelphax forms a distinct phyletic lineage within Echiniscidae, and Pseudechiniscinae are polyphyletic, with Mopsechiniscus being indirectly related to Pseudechiniscus, which is closer to the Echiniscus-like genera than to other genera with pseudosegmental plates. Consequently, the subfamilies and tribes are considered as unsupported from the phylogenetic and morphological point of view. The genus Cornechiniscus is revised, and the phenotypic diagnoses of several species are updated thanks to new rich material from Africa, Asia and Europe. Cornechiniscus imperfectus sp. nov. is described from mountains of Kyrgyzstan, being the second appendaged species within the genus and the third known to exhibit dioecy. A taxonomic key to the genus is provided. Systematic positions of Acanthechiniscus and Multipseudechiniscus are also discussed. Acanthechiniscus goedeni is confirmed to be a member of the genus Acanthechiniscus.
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Affiliation(s)
- Piotr Gąsiorek
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Łukasz Michalczyk
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
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Gąsiorek P, Vončina K, Degma P, Michalczyk Ł. Small is beautiful: the first phylogenetic analysis of Bryodelphax Thulin, 1928 (Heterotardigrada, Echiniscidae). ZOOSYST EVOL 2020. [DOI: 10.3897/zse.96.50821] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The phyletic relationships both between and within many of tardigrade genera have been barely studied and they remain obscure. Amongst them is the cosmopolitan Bryodelphax, one of the smallest in terms of body size echiniscid genera. The analysis of newly-found populations and species from the Mediterranean region and from South-East Asia gave us an opportunity to present the first phylogeny of this genus, which showed that phenotypic traits used in classical Bryodelphax taxonomy do not correlate with their phyletic relationships. In contrast, geographic distribution of the analysed species suggests their limited dispersal abilities and seems to be a reliable predictor of phylogenetic affinities within the genus. Moreover, we describe three new species of the genus. Bryodelphax australasiaticussp. nov., by having the ventral plate configuration VII:4-4-2-4-2-2-1, is a new member of the weglarskae group with a wide geographic range extending from the Malay Peninsula through the Malay Archipelago to Australia. Bryodelphax decoratussp. nov. from Central Sulawesi (Celebes) also belongs to the weglarskae group (poorly visible ventral plates VII:4-2-2-4-2-2-1) and is closely related to the recently described Bryodelphax arenosus Gąsiorek, 2018, but is differentiated from the latter by well-developed epicuticular granules on the dorsum. Finally, a new dioecious species, Bryodelphax nigripunctatussp. nov., is described from Mallorca and, by the reduced ventral armature (II/III:2-2-(1)), it resembles Bryodelphax maculatus Gąsiorek et al., 2017. The latter species, known so far only from northern Africa, is recorded from Europe for the first time. A taxonomic key to the genus members is also presented.
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Grobys D, Roszkowska M, Gawlak M, Kmita H, Kepel A, Kepel M, Parnikoza I, Bartylak T, Kaczmarek Ł. High diversity in the Pseudechiniscus suillus–facettalis complex (Heterotardigrada: Echiniscidae) with remarks on the morphology of the genus Pseudechiniscus. Zool J Linn Soc 2020. [DOI: 10.1093/zoolinnean/zlz171] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Pseudechiniscus is a morphologically homogeneous genus of tardigrades. The morphological features commonly used for species discrimination in this genus are the dorsal sculpture, the shape and number of dorsal plates and trunk appendages. Species of the Pseudechiniscus suillus–facettalis complex are one of the most challenging tardigrades to identify. All species are similar in their general appearance and all lack trunk appendages. Moreover, not only the nominal Pseudechiniscus suillus, but also other members of the suillus–facettalis complex have been insufficiently described. In our study, we examined several populations from the Northern and the Southern Hemispheres that could be traditionally attributed to Pse. suillus. These populations were analysed using integrative taxonomy – a combination of classical morphology and morphometry with molecular data. Besides the differences in the dorsal sculpture and morphometry, we also found species-specific differences in ventral sculpture, which were originally used for discrimination of Pseudechiniscus species. Moreover, we provide an extensive discussion on all morphological and morphometric differences used in Pseudechiniscus taxonomy and indicate main taxonomic problems with this genus. Finally, we redescribe the nominal Pse. suillus from Italy.
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Affiliation(s)
- Daria Grobys
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, Poznań, Poznań, Poland
| | - Milena Roszkowska
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, Poznań, Poznań, Poland
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poznań, Poland
| | - Magdalena Gawlak
- The Institute of Plant Protection-National Research Institute, Poznań, Poland
| | - Hanna Kmita
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, Poznań, Poznań, Poland
| | - Andrzej Kepel
- Polish Society for Nature Conservation ‘Salamandra’, Poznań, Poland
| | - Marta Kepel
- Polish Society for Nature Conservation ‘Salamandra’, Poznań, Poland
| | - Ivan Parnikoza
- National Antarctic Scientific Center of Ukraine, Kyiv, Ukraine
- Institute of Molecular Biology and Genetics of National Academy of Science of Ukraine, Kyiv, Ukraine
| | - Tomasz Bartylak
- Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, Poznań, Poznań, Poland
| | - Łukasz Kaczmarek
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poznań, Poland
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20
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Stec D, Krzywański Ł, Arakawa K, Michalczyk Ł. A new redescription of Richtersius coronifer, supported by transcriptome, provides resources for describing concealed species diversity within the monotypic genus Richtersius (Eutardigrada). ZOOLOGICAL LETTERS 2020; 6:2. [PMID: 32047649 PMCID: PMC7003491 DOI: 10.1186/s40851-020-0154-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 01/06/2020] [Indexed: 05/08/2023]
Abstract
Richtersius coronifer, the nominal species for the family Richtersiidae and a popular laboratory model, exemplifies a common problem in modern tardigrade taxonomy. Despite undeniable progress in the field, many old and incomplete descriptions of taxa hinder both species delimitation and the estimation of species diversity and distribution. Although for over a century this species has been recorded throughout the world, recent research indicates that records to date are likely to represent a species complex rather than a single cosmopolitan species. However, in order to recognise and name species diversity within the complex, an integrative redescription of the nominal species is first needed. Here, we describe an R. coronifer population collected from Spitsbergen, i.e., one of the two localities mentioned in the original description, with detailed morphological and morphometric data associated with standard DNA sequences of four standard genetic markers (18S rRNA, 28S rRNA, ITS-2, and COI) and supported by transcriptome sequencing. We propose replacement of the neotype designated in 1981 by Maucci and Ramazzotti, as it is impossible to verify whether the existing neotype is conspecific with specimens studied by Richters in 1903 and 1904. Finally, using newly obtained cytochrome c oxidase subunit I (COI) sequences of populations from Spitsbergen, Italy, Poland, and Greece together with sequences deposited in GenBank (China, Greenland, Italy, Mongolia), we performed genetic species delimitation, which indicated seven distinct potential species within the genus Richtersius, in addition to the nominal taxon. This study marks a starting point for further research on the taxonomy of and species diversity within the genus. Moreover, this work has the potential to be the first tardigrade redescription to provide both genetic barcodes and a transcriptome of the species in question.
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Affiliation(s)
- Daniel Stec
- Department of Entomology, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Łukasz Krzywański
- Department of Entomology, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Kazuharu Arakawa
- Institute for Advanced Biosciences, Keio University, Mizukami 246-2, Kakuganji, Tsuruoka, Yamagata, Japan
| | - Łukasz Michalczyk
- Department of Entomology, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
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Stec D, Krzywański Ł, Zawierucha K, Michalczyk Ł. Untangling systematics of the Paramacrobiotus areolatus species complex by an integrative redescription of the nominal species for the group, with multilocus phylogeny and species delineation in the genus Paramacrobiotus. Zool J Linn Soc 2020. [DOI: 10.1093/zoolinnean/zlz163] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abstract
Incomplete descriptions of nominal taxa are one of the most significant obstacles in modern taxonomy, including the taxonomy of Tardigrada. Another major problem in tardigrade systematics is the lack of tests for the reliability of genetic markers in species delineation. Here, we employ an integrative taxonomy approach to redescribe the nominal taxon for the P. areolatus complex, Paramacrobiotus areolatus. Moreover, we obtained multilocus DNA sequences for another 16 populations representing 9–12 Paramacrobiotus species collected from Europe, North America, Africa and Australia, enabling us to reconstruct the most extensive phylogeny of the genus to date. The identification of a pair of potentially cryptic dioecious P. areolatus complex species with divergent genetic distances in ITS2 (1.4%) and COI (13.8%) provided an opportunity to test the biological species concept for the first time in the history of tardigrade taxonomy. Intra- and interpopulation crosses did not differ in reproductive success in terms of F1 offspring. However, because of the low F1 family sizes, we were unfortunately unable to test F1 hybrid fertility. Although our results are only partially conclusive, they offer a baseline not only for further taxonomic and phylogenetic research on the areolatus complex, but also for studies on species delineation in tardigrades in general.
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Affiliation(s)
- Daniel Stec
- Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Łukasz Krzywański
- Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Krzysztof Zawierucha
- Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznań, Poznań, Poland
| | - Łukasz Michalczyk
- Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
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22
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Gąsiorek P, Blagden B, Michalczyk Ł. Towards a better understanding of echiniscid intraspecific variability: A redescription of Nebularmis reticulatus (Murray, 1905) (Heterotardigrada: Echiniscoidea). ZOOL ANZ 2019. [DOI: 10.1016/j.jcz.2019.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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23
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Cesari M, Montanari M, Kristensen RM, Bertolani R, Guidetti R, Rebecchi L. An integrated study of the biodiversity within the Pseudechiniscus suillus–facettalis group (Heterotardigrada: Echiniscidae). Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz045] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Abstract
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.
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Affiliation(s)
- Michele Cesari
- Department of Life Sciences, University of Modena and Reggio Emilia, Italy
| | - Martina Montanari
- Department of Life Sciences, University of Modena and Reggio Emilia, Italy
| | | | - Roberto Bertolani
- Department of Education and Humanities, University of Modena and Reggio Emilia, Italy
- Civic Museum of Natural History, Verona, Italy
| | - Roberto Guidetti
- Department of Life Sciences, University of Modena and Reggio Emilia, Italy
| | - Lorena Rebecchi
- Department of Life Sciences, University of Modena and Reggio Emilia, Italy
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Morek W, Michalczyk Ł. First extensive multilocus phylogeny of the genus Milnesium (Tardigrada) reveals no congruence between genetic markers and morphological traits. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz040] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Witold Morek
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa, Kraków, Poland
| | - Łukasz Michalczyk
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa, Kraków, Poland
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25
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Gąsiorek P, Vončina K. New Echiniscidae (Heterotardigrada) from Amber Mountain (Northern Madagascar). EVOLUTIONARY SYSTEMATICS 2019. [DOI: 10.3897/evolsyst.3.33580] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A moss sample from the local biodiversity hotspot in lowland rainforest in the vicinity of Amber Mountain, Madagascar, yielded the discovery of twoEchiniscusC.A.S. Schultze, 1840 species, of which one is new to science.Echiniscussuccineussp. nov.is related to other members of thespinulosusgroup, but differs from them by the highly complicated structure of the dorsal plates, with intricately thickened parts of the armour forming ornamented pattern. The validity of the intraporal dark rings as a taxonomic trait is discussed in the context of the recovered intraspecific variability for the new taxon. Besides, rareEchiniscusafricanusMurray, 1907 is reported for the first time from the island.
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Gąsiorek P, Michalczyk Ł. Echiniscus siticulosus (Echiniscidae: spinulosus group), a new tardigrade from Western Australian scrub. NEW ZEALAND JOURNAL OF ZOOLOGY 2019. [DOI: 10.1080/03014223.2019.1603166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Piotr Gąsiorek
- Department of Entomology, Institute of Zoology and Biomedical Research, Jagiellonian University Kraków, Poland
| | - Łukasz Michalczyk
- Department of Entomology, Institute of Zoology and Biomedical Research, Jagiellonian University Kraków, Poland
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Gąsiorek P, Morek W, Stec D, Michalczyk Ł. Untangling the
Echiniscus
Gordian knot: paraphyly of the “
arctomys
group” (Heterotardigrada: Echiniscidae). Cladistics 2019; 35:633-653. [DOI: 10.1111/cla.12377] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2019] [Indexed: 11/30/2022] Open
Affiliation(s)
- Piotr Gąsiorek
- Institute of Zoology and Biomedical Research Faculty of Biology Jagiellonian University Gronostajowa 9 30‐387 Kraków Poland
| | - Witold Morek
- Institute of Zoology and Biomedical Research Faculty of Biology Jagiellonian University Gronostajowa 9 30‐387 Kraków Poland
| | - Daniel Stec
- Institute of Zoology and Biomedical Research Faculty of Biology Jagiellonian University Gronostajowa 9 30‐387 Kraków Poland
| | - Łukasz Michalczyk
- Institute of Zoology and Biomedical Research Faculty of Biology Jagiellonian University Gronostajowa 9 30‐387 Kraków Poland
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28
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Gąsiorek P, Kristensen RM. Echiniscidae (Heterotardigrada) of Tanzania and Uganda. TROPICAL ZOOLOGY 2018. [DOI: 10.1080/03946975.2018.1477350] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Piotr Gąsiorek
- Department of Entomology, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Reinhardt Møbjerg Kristensen
- Section for Biosystematics, Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, Copenhagen Ø DK-2100, Denmark
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Gąsiorek P, Vončina K, Michalczyk Ł. Echiniscus testudo (Doyère, 1840) in New Zealand: anthropogenic dispersal or evidence for the ‘Everything is Everywhere’ hypothesis? NEW ZEALAND JOURNAL OF ZOOLOGY 2018. [DOI: 10.1080/03014223.2018.1503607] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Piotr Gąsiorek
- Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Katarzyna Vončina
- Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Łukasz Michalczyk
- Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
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30
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Morek W, Stec D, Gąsiorek P, Surmacz B, Michalczyk Ł. Milnesium tardigradum
Doyère, 1840: The first integrative study of interpopulation variability in a tardigrade species. J ZOOL SYST EVOL RES 2018. [DOI: 10.1111/jzs.12233] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Witold Morek
- Department of Entomology Institute of Zoology and Biomedical Research Jagiellonian University Kraków Poland
| | - Daniel Stec
- Department of Entomology Institute of Zoology and Biomedical Research Jagiellonian University Kraków Poland
| | - Piotr Gąsiorek
- Department of Entomology Institute of Zoology and Biomedical Research Jagiellonian University Kraków Poland
| | - Bartłomiej Surmacz
- Department of Entomology Institute of Zoology and Biomedical Research Jagiellonian University Kraków Poland
| | - Łukasz Michalczyk
- Department of Entomology Institute of Zoology and Biomedical Research Jagiellonian University Kraków Poland
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Stec D, Morek W, Gąsiorek P, Michalczyk Ł. Unmasking hidden species diversity within the Ramazzottius oberhaeuseri complex, with an integrative redescription of the nominal species for the family Ramazzottiidae (Tardigrada: Eutardigrada: Parachela). SYST BIODIVERS 2018. [DOI: 10.1080/14772000.2018.1424267] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Daniel Stec
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Witold Morek
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Piotr Gąsiorek
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Łukasz Michalczyk
- Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
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do Nascimento VD, Coelho KA, Nogaroto V, de Almeida RB, Ziemniczak K, Centofante L, Pavanelli CS, Torres RA, Moreira-Filho O, Vicari MR. Do multiple karyomorphs and population genetics of freshwater darter characines (Apareiodon affinis) indicate chromosomal speciation? ZOOL ANZ 2018. [DOI: 10.1016/j.jcz.2017.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Gąsiorek P, Suzuki AC, Kristensen RM, Lachowska-Cierlik D, Michalczyk Ł. Untangling the Echiniscus Gordian knot: Stellariscus gen. nov. (Heterotardigrada : Echiniscidae) from Far East Asia. INVERTEBR SYST 2018. [DOI: 10.1071/is18023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Species constituting the family Echiniscidae are highly derived, armoured and inhabit terrestrial habitats, in contrast to other heterotardigrades that are predominantly marine. The genus Echiniscus C.A.S. Schultze, 1840, nominal for the family Echiniscidae, is currently the most speciose tardigrade genus. However, the great morphological variability, in comparison with other heterotardigrade genera, suggests the polyphyletic character of the genus. Here, we analyse new specimens of Echiniscus pseudelegans Séméria, 1994 collected in Japan and conclude that the species as well as two other related taxa, E. elegans Richters, 1907 and E. latifasciatus Dudichev and Biserov, 2000, represent a new genus, Stellariscus, gen. nov. The new genus is characterised by a mixture of peculiar morphological apomorphies: black eyes, star-like dorsal plate sculpturing, no trunk appendages (only cephalic cirri present), two types of ventral plates, and striking sexual dimorphism in both qualitative and quantitative traits. Morphological phylogeny of the family Echiniscidae suggests a close affinity between Stellariscus, Hypechiniscus Thulin, 1928 and Pseudechiniscus Thulin, 1911. The polyphyletic status of both Echiniscus and Testechiniscus Kristensen, 1987 is also inferred. The taxonomic significance of ventral armature in echiniscid phylogeny and taxonomy is discussed.
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