Marine tardigrades from Lützow-Holm Bay, East Antarctica with the description of a new species

Fujimoto, Shinta; Suzuki, Atsushi; Ito, Motohiro; Tamura, Takeshi; Tsujimoto, Megumu

doi:10.1007/s00300-020-02671-w

Cited by 8 publications

(3 citation statements)

References 44 publications

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“…These structures comprise an evolutionary solution that allows females to lay more than one brood without the need to copulate again. Its existence is very widespread among the Myriapoda [81,82], worms [83], Chelicerata [84,85], Tardigrada [86,87], and Onychophora [88,89] and Insecta [90,91]. It must be considered that the moment of copulation tends to be one of the moments when the individuals are more defenceless against predators; therefore, the time is usually minimised.…”

Section: Discussionmentioning

confidence: 99%

Influence of Storage Time on the DNA Integrity and Viability of Spermatozoa of the Spider Crab Maja brachydactyla

Rodríguez-Pena,

Suárez,

Estévez-Pérez

et al. 2023

Animals

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Natural populations of the spider crab Maja brachydactyla constitute a fishery resource of great economic importance in many countries. As in the rest of eubrachyurans, the females of this species have ventral-type seminal receptacles where they store sperm from copulations. Sperm can be stored in these structures for months and even years before egg fertilisation, with the consequent degradation of the sperm cells during the time. In this work, we analyse the viability and the possible genetic damage in sperm accumulated in the seminal receptacles of M. brachydactyla females as a function of the storage time (from 0 to 14 months) using the comet assay technique. On one hand, we developed an algorithm for comet image analysis that improves the comet segmentation compared with the free software Open comet v1.3.1 (97% vs. 76% of detection). In addition, our software allows the manual modification of the contours wrongly delimited via the automatic tool. On the other hand, our data show a sharp decline in sperm viability and DNA integrity in the first four months of storage, which could lead to a decrease in the fecundity rate and/or viability of the embryos or larvae from the second and third clutches of the annual cycle if the repair capacity in these gametic cells is low.

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Section: Discussionmentioning

confidence: 99%

Influence of Storage Time on the DNA Integrity and Viability of Spermatozoa of the Spider Crab Maja brachydactyla

Rodríguez-Pena,

Suárez,

Estévez-Pérez

et al. 2023

Animals

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“…Based on this list, we recognized that 28.3% of the taxa have not been determined at a specific level, and in others, it has not been possible to delimit new taxa based solely on morphological characteristics, which is evidence of the absence of an integrative strategy for the study of tardigrades diversity. The use of integrative methods that include different types of observation of morphological characters, and molecular markers focused on the delimitation of taxa, has been documented in other works for the phylum [18,19,[103][104][105]. The use of a multidisciplinary approach that takes advantage of the complementarity between different techniques of analysis of morphological [106] and genetic variation analyses [107] will allow clarifying the status of the taxa in Mexico and will provide more robust identifications and hypotheses testing of species.…”

Section: Discussionmentioning

confidence: 99%

A Strategy to Provide a Present and Future Scenario of Mexican Biodiversity of Tardigrada

et al. 2022

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Although the number of known tardigrade taxa in Mexico has increased significantly in the last ten years, the knowledge of their diversity faces challenges, as more than half of the Mexican territory has no records of this phylum. Thus, we developed a strategy to provide a present and future scenario for understanding the Mexican biodiversity of Tardigrada, described the distribution patterns of the current recorded species, calculated the estimated richness, and the estimated taxonomic effort needed to complete the national inventory. We obtained 474 records of 105 taxa, belonging to 42 genera and 75 species, distributed in 12 of the 14 biogeographical provinces of Mexico. We found that 54.72% of the species are present in more than three world regions and 3.79% of species that have been recorded only in Mexican provinces. Distribution patterns could be recognized for 11 species, two of which have a Nearctic distribution, seven are Neotropical and two are distributed in both regions. The Mexican biogeographical provinces with the greatest diversity of tardigrades, both at specific and generic level, were the Transmexican Volcanic Belt (TVBP) and the Sierras Madre Oriental (SMOrP) and Sierra Madre Occidental (SMOcP), which have been previously identified as particularly species-rich regions. Diversity estimation methods predict that more than 290 species of tardigrades could be found in Mexico.

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“…Universal primers, including the widely used "Folmer primers" (Folmer et al 1994), generally bind to arthrotardigrade sequences with low affinity impairing amplification or amplifying non-tardigrade DNA (Jørgensen et al 2010). Notably, only four arthrotardigrade sequences of the mitochondrial cytochrome c oxidase subunit I (COI) are available to date: Batillipes pennaki (see Ryu et al 2007), Styraconyx takeshii (see Fujimoto et al 2020), Florarctus sp. (GenBank Accession number MT999946) and Batillipes longispinosus (KF938943), with Batillipes species represented by partial mitochondrial genome sequences.…”

Section: Introductionmentioning

confidence: 99%

Actinarctus doryphorus (Tanarctidae) DNA barcodes and phylogenetic reinvestigation of Arthrotardigrada with new A. doryphorus and Echiniscoididae sequences

GROLLMANN,

JØRGENSEN,

MØBJERG

2023

Zootaxa

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Little is still known about the diversity and evolution of marine arthrotardigrades, as they are generally difficult to sample, resulting in a limited amount of molecular data for barcoding and phylogenetic studies. With the current study, we provide the first investigation into COI haplotype diversity in a marine tanarctid and at the same time readdress arthrotardigrade phylogeny. Specifically, we provide COI mtDNA, 18S and 28S rDNA sequences from a population of Actinarctus doryphorus (Tanarctidae) sampled off the coast of Roscoff, France and further provide new 18S sequences from two marine echiniscoidids. A. doryphorus COI sequences confirmed the presence of a single species and further revealed five haplotypes shared among nine sequenced individuals. Our 18S and 28S rDNA datasets were individually and combined analysed with Bayesian inference and Maximum Likelihood. Actinarctus doryphorus was placed together with Tanarctus sequences within a maximally supported Tanarctidae, confirming previous interpretations that the clade is distinct from Halechiniscidae. Although several studies in recent decades have concluded that the marine arthrotardigrades are paraphyletic, recent studies have argued that the clade may not be paraphyletic. Our phylogenetic analyses consistently inferred Arthrotardigrada as paraphyletic, as the clade includes the monophyletic Echiniscoidea. Accordingly, we propose that it is time to suppress the order Arthrotardigrada as it clearly does not reflect tardigrade phylogeny.

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Marine tardigrades from Lützow-Holm Bay, East Antarctica with the description of a new species

Cited by 8 publications

References 44 publications

Influence of Storage Time on the DNA Integrity and Viability of Spermatozoa of the Spider Crab Maja brachydactyla

Influence of Storage Time on the DNA Integrity and Viability of Spermatozoa of the Spider Crab Maja brachydactyla

A Strategy to Provide a Present and Future Scenario of Mexican Biodiversity of Tardigrada

Actinarctus doryphorus (Tanarctidae) DNA barcodes and phylogenetic reinvestigation of Arthrotardigrada with new A. doryphorus and Echiniscoididae sequences

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