Nunduva, a new marine genus of Rivulariaceae (Nostocales, Cyanobacteria) from marine rocky shores

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A population of Desertifilum (Cyanobacteria, Oscillatoriales) from an oligotrophic desertic biotope was isolated and characterized using a polyphasic approach including molecular, morphological, and ecological information. The population was initially assumed to be a new species based on ecological and biogeographic separation from other existing species, however, phylogenetic analyses based on sequences of the 16S rRNA gene and 16S–23S ITS region, placed this strain clearly within the type species, Desertifilum tharense. Comparative analysis of morphology, 16S rRNA gene similarity, 16S–23S ITS secondary structure, and percent dissimilarity of the ITS regions for all characterized strains supports placing the six Desertifilum strains (designated as PD2001/TDC17, UAM‐C/S02, CHAB7200, NapGTcm17, IPPAS B‐1220, and PMC 872.14) into D. tharense. The recognition of Desertifilum salkalinema and Desertifilum dzianense is not supported, although our analysis does support continued recognition of Desertifilum fontinale. Pragmatic criteria for recognition of closely related species are proposed based on this study and others, and more rigorous review of future taxonomic papers is recommended.

“…, Mareš et al. ). Phylogenetic analyses of aligned orthologous ITS regions can also be useful in demonstrating reciprocal monophyly within species (Perkerson et al.…”

Section: Discussionmentioning

confidence: 98%

“…While genera are rather unambiguously defined (a collection of species that forms a monophyletic taxon, see González‐Resendiz et al. ), the discussion over what constitutes a species is still a matter of serious debate (Johansen and Casamatta , Komárek , Dvořák et al. ).…”

Section: Discussionmentioning

confidence: 99%

A bridge too far in naming species: a total evidence approach does not support recognition of four species in Desertifilum (Cyanobacteria)

González-Resendiz

Johansen

León‐Tejera

et al. 2019

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“…2014a, González‐Resendiz et al. ,b) is in the ambiguous range of 0.055 < P < 0.065 (Table ), indicating that the process of speciation is still underway based on this recognition criterion.…”

Section: Discussionmentioning

confidence: 98%

When Is A Lineage A Species? A Case Study In Myxacorys gen. nov. (Synechococcales: Cyanobacteria) With The Description of Two New Species From The Americas

Pietrasiak

Osorio‐Santos

Shalygin

et al. 2019

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Soil cyanobacteria are crucial components of biological soil crusts and carry out many functions in dryland ecosystems. Despite this importance, their taxonomy and population genetics remain poorly known. We isolated 42 strains of simple filamentous cyanobacteria previously identified as Pseudophormidium hollerbachianum from 26 desert locations in the North and South America and characterized these strains using a total evidence approach, that is, using both morphological and molecular data to arrive at taxonomic decisions. Based on a phylogenetic analysis of 16S rRNA gene sequences, we propose and characterize Myxacorys gen. nov. with two new species Myxacorys chilensis, the generitype, and M. californica. We also found distinct 16S‐23S ITS sequence variability within species in our dataset. Especially interesting was the presence of two distinct lineages of M. californica obtained from locations in close spatial proximity (within a few meters to kilometers from each other) suggesting niche differentiation. The detection of such unrecognized lineage‐level variability in soil cyanobacteria has important implications for biocrust restoration practices and conservation efforts.

“…, González‐Resendiz et al. ). Phylogenies of the Rivulariaceae typically show an intermixing of Calothrix and Rivularia species when based upon strains from culture collections, and the type species for both genera require sequencing in order to determine to which genera and species strains belong.…”

mentioning

confidence: 99%

“…Calochaete, Roholtiella, and Macrochaete have been split out of Calothrix (Hauer et al 2013, Bohunick a et al 2015a, Berrendero et al 2016, whereas Cyanomargarita has been described as a cryptic genus inseparable morphologically from Rivularia (Shalygin et al 2017). Kyrtuthrix and Nunduva belong to a clade of marine Rivulariaceae that has a number of potentially new genera and species based on phylogenetic and morphological evidence (Le on-Tejera et al , Gonz alez-Resendiz et al 2018. Phylogenies of the Rivulariaceae typically show an intermixing of Calothrix and Rivularia species when based upon strains from culture collections, and the type species for both genera require sequencing in order to determine to which genera and species strains belong.…”

mentioning

confidence: 99%

Two new species of Phyllonema (Rivulariaceae, Cyanobacteria) with an emendation of the genus

González-Resendiz

Johansen

Escobar‐Sánchez

et al. 2018

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Two untapered, heterocytous species were observed and collected from the intertidal and supratidal zones of the Mexican coastline of the Pacific Ocean near Oaxaca and from the Gulf of Mexico. These populations were highly similar in morphology to the freshwater taxon Petalonema incrustans in the Scytonemataceae. However, 16S rRNA sequence data and phylogenetic analysis indicated that they were sister taxa to the epiphyllic, Brazilian species Phyllonema aveceniicola in the Rivulariaceae, described from culture material. While genetic identity between the two new species was high, they differed significantly in morphology, 16S rRNA gene sequence identity, and sequence and structure of the 16S-23S ITS region. Their morphology differed markedly from the generitype of the previously monotypic Phyllonema, which has tapered, heteropolar, single-false branched trichomes with very thin or absent sheath. The two new species, Phyllonema ansata and Phyllonema tangolundensis, described from both culture and environmental material, have untapered, isopolar, geminately false branched trichomes with thick, lamellated sheaths, differences so significant that the species would not be placed in Phyllonema without molecular corroboration. The morphological differences are so significant that a formal emendation of the genus is required. These taxa provide a challenge to algal taxonomy because the morphological differences are such that one would logically conclude that they represent different genera, but the phylogenetic evidence for including them all in the same genus is conclusive. This conclusion is counter to the current trend in algal taxonomy in which taxa with minor morphological differences have been repeatedly placed in separate genera based primarily upon DNA sequence evidence.