Species Diversity of<i>Ramphogordius sanguineus/Lineus ruber</i>-Like Nemerteans (Nemertea: Heteronemertea) and Geographic Distribution of<i>R. sanguineus</i>

Kang, Xingxing; Fernández-Álvarez, Fernando Ángel; Alfaya, José E. F.; Machordom, Annie; Strand, Malin; Sundberg, Per; Sun, Shichun

doi:10.2108/zs150064

Cited by 26 publications

(35 citation statements)

References 43 publications

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“…When topology constraints were enforced (see Methods), the resulting inferences differed only in the enforced bipartitions, but the internal topology of the remaining clades did not differ from the unconstrained trees. Our results are similar overall to those of previous studies [29][30][31]55,56], and are further described in the electronic supplementary material.…”

Section: Sequencing and Phylogenetic Framework Inferencesupporting

confidence: 91%

A phylum-wide survey reveals multiple independent gains of head regeneration ability in Nemertea

Zattara

Fernández-Álvarez

Hiebert

et al. 2018

Preprint

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Animals vary widely in their ability to regenerate, suggesting that regenerative abilities have a rich evolutionary history. However, our understanding of this history remains limited because regeneration ability has only been evaluated in a tiny fraction of species. Available comparative regeneration studies have identified losses of regenerative ability, yet clear documentation of gains is lacking. We surveyed regenerative ability in 34 species spanning the phylum Nemertea, assessing the ability to regenerate heads and tails either through our own experiments or from literature reports. Our sampling included representatives of the 10 most diverse families and all three orders comprising this phylum. We generated a phylogenetic framework using sequence data to reconstruct the evolutionary history of head and tail regeneration ability across the phylum and found that while all evaluated species can remake a posterior end, surprisingly few could regenerate a complete head. Our analysis reconstructs a nemertean ancestor unable to regenerate a head and indicates at least four separate lineages have independently gained head regeneration ability, one such gains reconstructed as taking place within the last 10-15 mya. Our study highlights nemerteans as a valuable group for studying evolution of regeneration and identifying mechanisms associated with repeated gains of regenerative ability.

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Section: Sequencing and Phylogenetic Framework Inferencesupporting

confidence: 91%

A phylum-wide survey reveals multiple independent gains of head regeneration ability in Nemertea

Zattara

Fernández-Álvarez

Hiebert

et al. 2018

Preprint

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“…The discrepancy in detected entities by non-tree-based methods is due to the applied threshold of dissimilarity for separating entities. The most commonly applied threshold to separate nemertean lineages based on the COI gene sequence is 5% (Chen et al, 2010;Kang et al, 2015;Krämer et al, 2017;Sundberg, Thuroczy Vodoti, et al, 2009). Setting the threshold to extreme levels of 1% and 10% dissimilarity for separating entities results in considerably more or less recognized lineages, respectively.…”

Section: Comparison Of Molecular Genetic Species Delimitation Methodsmentioning

confidence: 99%

“…Moreover, a DNA-based approach is deemed pivotal to detect unrecognized nemertean species (Chernyshev, Polyakova, Turanov, & Kajihara, 2018;Krämer et al, 2017;Mendes, Norenburg, Solferini, & Andrade, 2018;Strand & Sundberg, 2005;Sundberg, Thuroczy Vodoti, Zhou, & Strand, 2009) the number of which is assumed to be relatively high (Appeltans et al, 2012;Sundberg, Kvist, et al, 2016). Molecular genetic methods, like tree-based, non-tree-based, and phylogenetic analyses have been successfully applied to delimit species and discover cryptic species in different nemertean genera (Chen et al, 2010;Chernyshev et al, 2018;Fernández-Álvarez & Machordom, 2013;Kang et al, 2015;Krämer et al, 2017;Leasi & Norenburg, 2014;Mendes et al, 2018;Strand & Sundberg, 2005;Sundberg, Thuroczy Vodoti, et al, 2009;Sundberg, Kvist, et al, 2016).…”

mentioning

confidence: 99%

Assessing the diversity and distribution ofCephalothrixspecies (Nemertea: Palaeonemertea) in European waters by comparing different species delimitation methods

Sagorny

Wesseler

Krämer

et al. 2019

J Zool Syst Evol Res

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Soft‐bodied marine taxa, like ribbon worms (Nemertea), often lack clear diagnostic morphological characters impeding traditional species delimitation. Therefore, recent studies concentrated on molecular genetic methods to solve taxonomic issues. Different delimitation methods were employed to explore species boundaries and the presence of cryptic species. However, the performance of the different delimitation methods needs to be tested. A particularly promising nemertean genus in this regard is the palaeonemertean genus Cephalothrix that is commonly found in European waters. In order to gain information on the number and distribution of European cephalotrichids and to test different tree‐based and non‐tree‐based delimitation methods, we analyzed a dataset comprising the barcoding region of the mitochondrial cytochrome c oxidase subunit I (COI) of 215 European Cephalothrix specimens, of which 78 were collected for this study. Our results show the presence of 12–13 European lineages of which several can be assigned to known European species. Analyzing a second dataset comprising 74 additional sequences from the Pacific and the Atlantic Oceans helped identify some of the unassigned European specimens. One resulting clade seems to represent a non‐native introduced Cephalothrix species, while another has never been recorded from Europe before. In our analysis, especially the tree‐based methods and the phylogenetic analysis proved to be a useful tool when delimiting species. It remains unclear whether the different identified clades result from cryptic speciation or from a high genetic variability of the COI gene.

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“…Despite recent efforts (Kang et al . ), their taxonomic status is currently unclear, mainly because of insufficient phylogenetic resolution.…”

Section: Introductionmentioning

confidence: 99%

“…Riser 1994;Sundberg & Saur 1998;Kajihara et al 2008;Herrera-Bachiller et al 2015). Despite recent efforts (Kang et al 2015), their taxonomic status is currently unclear, mainly because of insufficient phylogenetic resolution.…”

Section: Introductionmentioning

confidence: 99%

Population genomics of sexual and asexual lineages in fissiparous ribbon worms (Lineus, Nemertea): hybridization, polyploidy and the Meselson effect

et al. 2016

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Comparative population genetics in asexual vs. sexual species offers the opportunity to investigate the impact of asexuality on genome evolution. Here, we analyse coding sequence polymorphism and divergence patterns in the fascinating Lineus ribbon worms, a group of marine, carnivorous nemerteans with unusual regeneration abilities, and in which asexual reproduction by fissiparity is documented. The population genomics of the fissiparous L. pseudolacteus is characterized by an extremely high level of heterozygosity and unexpectedly elevated πN /πS ratio, in apparent agreement with theoretical expectations under clonal evolution. Analysis of among-species allele sharing and read-count distribution, however, reveals that L. pseudolacteus is a triploid hybrid between Atlantic populations of L. sanguineus and L. lacteus. We model and quantify the relative impact of hybridity, polyploidy and asexuality on molecular variation patterns in L. pseudolacteus and conclude that (i) the peculiarities of L. pseudolacteus population genomics result in the first place from hybridization and (ii) the accumulation of new mutations through the Meselson effect is more than compensated by processes of heterozygosity erosion, such as gene conversion or gene copy loss. This study illustrates the complexity of the evolutionary processes associated with asexuality and identifies L. pseudolacteus as a promising model to study the first steps of polyploid genome evolution in an asexual context.

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Species Diversity ofRamphogordius sanguineus/Lineus ruber-Like Nemerteans (Nemertea: Heteronemertea) and Geographic Distribution ofR. sanguineus

Cited by 26 publications

References 43 publications

A phylum-wide survey reveals multiple independent gains of head regeneration ability in Nemertea

A phylum-wide survey reveals multiple independent gains of head regeneration ability in Nemertea

Assessing the diversity and distribution ofCephalothrixspecies (Nemertea: Palaeonemertea) in European waters by comparing different species delimitation methods

Population genomics of sexual and asexual lineages in fissiparous ribbon worms (Lineus, Nemertea): hybridization, polyploidy and the Meselson effect

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