Evolutionary scenarios for the origin of an Antarctic tardigrade species based on molecular clock analyses and biogeographic data

Guidetti, Robertos; McInnes, Sandra J.; Cesari, Michele; Rebecchi, Lorena; Rota‐Stabelli, Omar

doi:10.1163/18759866-08602001

Cited by 27 publications

(24 citation statements)

References 54 publications

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“…Even accounting for the uncertainties of the estimated divergence times (see bars in Fig. 2) and the many prior assumptions embedded in the molecular clock of Antarctic organisms [85], our data exclude the hypothesis that the evolution of these bacterial clades was driven in response to the environmental pressure of the more recent Antarctica geological history. In fact, the last cooling events started once Antarctica reached the South Pole in the early Oligocene (~34 Ma), after the separation from Gondwanaland about 200 Ma [86], while the present icy conditions were established round 3 Ma.…”

Section: Discussionmentioning

confidence: 51%

Pre-Cambrian roots of novel Antarctic cryptoendolithic bacterial lineages

et al. 2021

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Background Cryptoendolithic communities are microbial ecosystems dwelling inside porous rocks that are able to persist at the edge of the biological potential for life in the ice-free areas of the Antarctic desert. These regions include the McMurdo Dry Valleys, often accounted as the closest terrestrial counterpart of the Martian environment and thought to be devoid of life until the discovery of these cryptic life-forms. Despite their interest as a model for the early colonization by living organisms of terrestrial ecosystems and for adaptation to extreme conditions of stress, little is known about the evolution, diversity, and genetic makeup of bacterial species that reside in these environments. Using the Illumina Novaseq platform, we generated the first metagenomes from rocks collected in Continental Antarctica over a distance of about 350 km along an altitudinal transect from 834 up to 3100 m above sea level (a.s.l.). Results A total of 497 draft bacterial genome sequences were assembled and clustered into 269 candidate species that lack a representative genome in public databases. Actinobacteria represent the most abundant phylum, followed by Chloroflexi and Proteobacteria. The “Candidatus Jiangella antarctica” has been recorded across all samples, suggesting a high adaptation and specialization of this species to the harshest Antarctic desert environment. The majority of these new species belong to monophyletic bacterial clades that diverged from related taxa in a range from 1.2 billion to 410 Ma and are functionally distinct from known related taxa. Conclusions Our findings significantly increase the repertoire of genomic data for several taxa and, to date, represent the first example of bacterial genomes recovered from endolithic communities. Their ancient origin seems to not be related to the geological history of the continent, rather they may represent evolutionary remnants of pristine clades that evolved across the Tonian glaciation. These unique genomic resources will underpin future studies on the structure, evolution, and function of these ecosystems at the edge of life.

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Section: Discussionmentioning

confidence: 51%

Pre-Cambrian roots of novel Antarctic cryptoendolithic bacterial lineages

et al. 2021

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“…Of the 64 limno-terrestrial genera of tardigrades, 11 are considered endemic at continental level [12], and continental endemism at the species level can be up to 60% [148]. In addition, species of the genus Mopsechiniscus follows the geological division of Gondwanan landmasses [150]. For tardigrades, biogeography indeed makes sense.…”

Section: Biogeographymentioning

confidence: 99%

Long-distance passive dispersal in microscopic aquatic animals

Fontaneto

2019

Mov Ecol

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Given their dormancy capability (long-term resistant stages) and their ability to colonise and reproduce, microscopic aquatic animals have been suggested having cosmopolitan distribution. Their dormant stages may be continuously moved by mobile elements through the entire planet to any suitable habitat, preventing the formation of biogeographical patterns. In this review, I will go through the evidence we have on the most common microscopic aquatic animals, namely nematodes, rotifers, and tardigrades, for each of the assumptions allowing longdistance dispersal (dormancy, viability, and reproduction) and all the evidence we have for transportation, directly from surveys of dispersing stages, and indirectly from the outcome of successful dispersal in biogeographical and phylogeographical studies. The current knowledge reveals biogeographical patterns also for microscopic organisms, with species-specific differences in ecological features that make some taxa indeed cosmopolitan with the potential for long-distance dispersal, but others with restricted geographic distributions.

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“…Currently, ca. 75 tardigrade species have been reported from continental Antarctic and few from other regions (for review see [12] and later publications [2,[13][14][15][16][17][18][19][20][21][22][23][24]).…”

Section: Introductionmentioning

confidence: 99%

New Records of Antarctic Tardigrada with Comments on Interpopulation Variability of the Paramacrobiotus fairbanksi Schill, Förster, Dandekar and Wolf, 2010

et al. 2020

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Studies on Antarctic tardigrades started at the beginning of the twentieth century and have progressed very slowly and ca. 75 tardigrade species are known from this region. Paramacrobiotus fairbanksi was described from USA based on genetic markers and later reported from Italy, Poland, and Spain. The “everything is everywhere” hypothesis suggests that microscopic organisms have specific features which help them to inhabit most of environments and due to this they can be considered cosmopolitan. In the present paper, we report eight tardigrade taxa from Antarctic, including the first report of Pam. fairbanksi from Southern Hemisphere, which could suggest that the “everything is everywhere” hypothesis could be true, at least for some tardigrade species. Moreover, we also genetically and morphologically compare a few different populations of Pam. fairbanksi. The p-distances between COI haplotypes of all sequenced Pam. fairbanksi populations from Antarctica, Italy, Spain, USA and Poland ranged from 0.002% to 0.005%. In the case of COI polymorphism analyses, only one haplotype was observed in populations from Antarctica, USA and Poland, two haplotypes were found in population from Spain, and six haplotypes were observed in population from Italy. We also found some statistically significant morphometrical differences between the populations of Pam. fairbanksi from different regions and designed a new specific primers for Paramacrobiotus taxa.

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Evolutionary scenarios for the origin of an Antarctic tardigrade species based on molecular clock analyses and biogeographic data

Cited by 27 publications

References 54 publications

Pre-Cambrian roots of novel Antarctic cryptoendolithic bacterial lineages

Pre-Cambrian roots of novel Antarctic cryptoendolithic bacterial lineages

Long-distance passive dispersal in microscopic aquatic animals

New Records of Antarctic Tardigrada with Comments on Interpopulation Variability of the Paramacrobiotus fairbanksi Schill, Förster, Dandekar and Wolf, 2010

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