Genetic diversity in the parthenogenetic reproducing tardigrade Echiniscus testudo (Heterotardigrada: Echiniscoidea)

Jørgensen, Aslak; Faurby, Søren; Persson, Dennis K.; Halberg, Kenneth A.; Kristensen, Reinhardt Møbjerg; Møbjerg, Nadja

doi:10.4081/jlimnol.2013.s1.e17

Cited by 15 publications

(12 citation statements)

References 28 publications

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“…In each examined sample only one species was identified. The same result was reported by Guidetti et al [13] in a study on parthenogenetic and amphimictic species of the tardigrade genus Richtersius, while other studies on parthenogenetic species evidenced a mix of haplotypes within the same sample both for the cox1 gene (in Echiniscus [8], in Milnesium [73]) and the ITS2 gene (but not for the cox1 gene in Ramazzottius [74]). In many cases, the substrate colonized by the P. richtersi complex is very similar; therefore it is possible to speculate that the absence of syntopy could be due to the competition or mutual exclusion among species, such that only one species prevails.…”

Section: Discussionsupporting

confidence: 85%

“…The presence of cryptic tardigrade species, evidenced by molecular methods, has also been reported in the literature [8–17]. In fact, in tardigrades genetic diversity within the same morphotype was observed before the use of DNA barcoding.…”

Section: Introductionmentioning

confidence: 69%

“…Amphimictic species have often reduced/local distribution, while parthenogenetic species have widespread distribution (e.g. in Echiniscus and Richtersius ; [8, 13, 63]). To date, the only exception is represented by the amphimictic species Macrobiotus macrocalix Bertolani and Rebecchi [60], identified with a molecular approach in Italy (in Apennines and Alps; [39]), Sweden [39], Poland [64], and Portugal [65], while the morpho-species was also cited in Poland [66], Austria [67], Albania [68], Spain [69], and Seychelles Islands [70].…”

Section: Discussionmentioning

confidence: 99%

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High diversity in species, reproductive modes and distribution within the Paramacrobiotus richtersi complex (Eutardigrada, Macrobiotidae)

et al. 2019

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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.Electronic supplementary materialThe online version of this article (10.1186/s40851-018-0113-z) contains supplementary material, which is available to authorized users.

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Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 99%

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High diversity in species, reproductive modes and distribution within the Paramacrobiotus richtersi complex (Eutardigrada, Macrobiotidae)

et al. 2019

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“…Species widely distributed in the Arctic and Europe, with a high dispersal potential (Jørgensen et al, 2007(Jørgensen et al, , 2013. The reports from the other localities, e.g., from South America, need confirmation .…”

Section: Echiniscus Blumimentioning

confidence: 99%

Tardigrada of Bory Tucholskie National Park, Zaborski Landscape Park, and their surroundings (Pomerania Province, Poland)

Kaczmarek¹,

Kosicki²,

Roszkowska³

2018

Turk J Zool

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“…Therefore, the analyzed morphological and morphometric variation was limited to phenotypic plasticity induced by environmental factors. On the other hand, the few available works that analyzed multiple populations of several tardigrade species focused almost exclusively on genetic variation, without a detailed comparisons of variability in morphological and morphometric traits within and between populations (Cesari, McInnes, Bertolani, Rebecchi, & Guidetti, ; Gąsiorek et al., ; Jørgensen, Møbjerg, & Kristensen, ; Jørgensen et al., ). Importantly, without integrative studies of intra‐ and interspecific variability, our power to delimit species will remain limited.…”

Section: Introductionmentioning

confidence: 99%

Milnesium tardigradum Doyère, 1840: The first integrative study of interpopulation variability in a tardigrade species

Morek

Stec

Gąsiorek

et al. 2018

J Zool Syst Evol Res

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Intraspecific variability of tardigrades is a poorly investigated field. The great majority of tardigrade species were described using single populations, sometimes even single individuals. Moreover, intraspecific variability between multiple, integratively verified populations has never been described for any tardigrade species. In this study, we analyzed morphological, morphometric, and genetic variability of nine European populations of Milnesium tardigradum, one of the first described tardigrade species that until recently was thought to be cosmopolitan. We found that the nine populations of M. tardigradum exhibited low to moderate diversity in the nuclear ITS‐2 marker (0.2%–4.0%, 1.1% on average) and low to high divergence in the mitochondrial COI fragment (0.2%–11.4%, 4.4% on average). Despite the considerable variability in COI, all M. tardigradum populations exhibited mostly uniform morphology and morphometry. Moreover, we analyzed ontogenetic variability in claw and lamellae configuration under scanning electron microscopy, which resulted in the description of novel taxonomically important traits for M. tardigradum. The phylogenetic analysis unambiguously showed that all GenBank sequences predating the redescription of M. tardigradum and labeled as “M. tardigradum” or “M. cf. tardigradum” represent other species. Thus, the neotype population from Germany and the additional eight European populations analyzed in this study are the only confirmed records of M. tardigradum to date. Finally, in order to clarify ontogenetic nomenclature, we propose distinct names for the first and second immature instars in the order Apochela (hatchling and juvenile, respectively) and concise definitions of time and direction of ontogenetic changes in claw configuration (i.e., early/late and positive/negative change).

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Genetic diversity in the parthenogenetic reproducing tardigrade Echiniscus testudo (Heterotardigrada: Echiniscoidea)

Abstract: Little

Cited by 15 publications

References 28 publications

High diversity in species, reproductive modes and distribution within the Paramacrobiotus richtersi complex (Eutardigrada, Macrobiotidae)

High diversity in species, reproductive modes and distribution within the Paramacrobiotus richtersi complex (Eutardigrada, Macrobiotidae)

Tardigrada of Bory Tucholskie National Park, Zaborski Landscape Park, and their surroundings (Pomerania Province, Poland)

Milnesium tardigradum Doyère, 1840: The first integrative study of interpopulation variability in a tardigrade species

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