An investigation into the morphology and genetics of<i>Cyclotella comensis</i>and closely related taxa

Diatoms are one of the most abundant and arguably the most species‐rich group of protists. Diatom species delimitation has often been based exclusively on the recognition of morphological discontinuities without investigation of other lines of evidence. Even though DNA sequences and reproductive experiments have revealed several examples of (pseudo)cryptic diversity, our understanding of diatom species boundaries and diversity remains limited. The cosmopolitan pennate raphid diatom genus Pinnularia represents one of the most taxon‐rich diatom genera. In this study, we focused on the delimitation of species in one of the major clades of the genus, the Pinnularia subgibba group, based on 105 strains from a worldwide origin. We compared genetic distances between the sequences of seven molecular markers and selected the most variable pair, the mitochondrial cox1 and nuclear encoded LSU rDNA, to formulate a primary hypothesis on the species limits using three single‐locus automated species delimitation methods. We compared the DNA‐based primary hypotheses with morphology and with other available lines of evidence. The results indicate that our data set comprised 15 species of the P. subgibba group. The vast majority of these taxa have an uncertain taxonomic identity, suggesting that several may be unknown to science and/or members of (pseudo)cryptic species complexes within the P. subgibba group.

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“…, Kistenich et al. ). Specifically in Pinnularia , it was used for phylogenetic inferences of the entire genus, including Caloneis (Bruder et al.…”

Section: Discussionmentioning

confidence: 98%

“…, Kistenich et al. ). For molecular species delimitation, (i) a “barcode gap” should be present (i.e., the intraspecific variation must be distinctly lower than the interspecific variation) and (ii) the markers should be variable enough to distinguish between closely related species.…”

mentioning

confidence: 98%

A polyphasic approach to the delimitation of diatom species: a case study for the genusPinnularia(Bacillariophyta)

Kollár

Pinseel

Vanormelingen

et al. 2019

Journal of Phycology

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“…For culturing conditions see kistenicH et al (2014). Molecular results of our previous studies (kistenicH et al 2014(kistenicH et al , DulebA et al 2015 were used for comparison; information about details of culturing, molecular methods and phylogenetic analyses are available therein.…”

Section: Methodsmentioning

confidence: 99%

Pantocsekiella, a new centric diatom genus based on morphological and genetic studies

Ács¹,

Ari²,

Duleba³

et al. 2016

Fottea

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Previous morphological studies showed that the description of the Cyclotella genus was too general and according to new morphological criteria new genera were established based on both recent and fossil taxa (e.g. Discostella, Handmannia, Puncticulata, Tertiarius). Furthermore, previous molecular biological investigations proved that the Cyclotella genus was not monophyletic. Integrating the above mentioned knowledge the former Cyclotella genus has been split into 4 genera (Cyclotella s.s., Discostella, Tertiarius and Lindavia). Based on the position of rimoportula Lindavia genus was formed for involving the species of both the Cyclotella ocellata and C. bodanica lineages. Our morphological and molecular (genetic distance and phylogenetic analyses of rbcL and 18S rDNA sequences) investigations suggested that "Lindavia/Cyclotella ocellata group" could be raised from the Lindavia as a separate genus. Its distinctive morphological features are the followings: striae unequal in length, central area without areolae. We describe the new genus Pantocsekiella gen. nov. and we transferred several Lindavia taxa into it. We also provide an amended diagnosis for the genus Lindavia.

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“…Recent revisions and/or descriptions of new centric diatom genera like Stephanocostis (Genkal & Kuzmina, 1985), Discostella (Houk & Klee, 2004), Spicaticribra (Johansen et al, 2008), Lindavia (Nakov et al, 2015) and Pantocsekiella (Á cs et al, 2016) have increased our knowledge about the diversity of freshwater centric diatoms (Karthick & Kociolek, 2011), but also stressed a further need for detailed phylogenetic analyses of this group of taxa (Kociolek & Khursevich, 2013). In particular, difficulties like barely discernible differences in the morphological structures under light and scanning electron microscopy (Kling & Håkansson, 1988;Abonyi et al, 2012;Kistenich et al, 2014), interspecific similarity (Sabater & Klee, 1990), and largely unknown species ecology (Sládeček, 1986) greatly account for erroneous or inaccurate species identifications (Håkansson & Kling, 1994) and related misplacements into FGs. Therefore, both taxonomical accuracy and precise functional characterization (Izaguirre et al, 2012;Ž utinić et al, 2014) are fundamental for adequate ecological assessments (Cavalcante et al, 2013) and monitoring studies (Holzenthal et al, 2010;Martín & Reyes Fernández, 2012).…”

Section: Assemblage Analysesmentioning

confidence: 99%

“…Furthermore, physiological properties and ecotype placement (Gligora Udovič et al, 2015) of Lake Vransko is congruent with the placement of its dominant, typifying species into codon A. Pantocsekiella costei was originally described by Druart & Straub (1988) as Cyclotella costei during an ecological and palaeoecological study of a small alkaline, eutrophic lake Paladru (France). Pantocsekiella costei (Cyclotella costei) is closely related and probably conspecific with C. comensis and C. pseudocomensis (Kistenich et al, 2014;Duleba et al, 2015). Håkansson & Carter (1990) described Cyclotella cyclopuncta from Plitvice Lakes, but later taxonomic analyses of Houk et al (2010) showed that both species share the same morphological features, and thus, C. cyclopuncta was considered a synonym of P. costei.…”

Section: Assemblage Analysesmentioning

confidence: 99%

Defining centric diatoms of most relevant phytoplankton functional groups in deep karst lakes

et al. 2016

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Phytoplankton in karst lakes is characterized by co-occurrence of chrysophytes (Chrysophyceae), dinoflagellates (Dinophyceae), and diatoms (Bacillariophyta) as the most diverse and abundant group. Using Reynolds functional approach in ecological phytoplankton investigations makes karstic lakes comparable and facilitates interpretation of their responses to changing environmental conditions. Accurate taxonomic identification to species level, based on precise resolution of specific characteristics by electron microscopy, is essential in order to correctly associate species into coda. This paper defines the most abundant centric diatoms and coexisting species in the phytoplankton of karst lakes in Croatia as a contribution to better description of phytoplankton functional groups dominated by centric diatoms. Several representatives for diatom-based Reynolds functional groups of four lakes in Croatia were described in this paper: Pantocsekiella costei and Stephanocostis chantaica for group A, Pantocsekiella ocellata and Cyclotella distinguenda for group B, and Stephanodiscus neoastraea for group C, together with their ecological preferences which clearly correspond to pertaining functional classification. Selected and coexisting functional groups define natural, oligo-to mesotrophic karst deep lake systems.

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An investigation into the morphology and genetics ofCyclotella comensisand closely related taxa

Cited by 17 publications

References 33 publications

A polyphasic approach to the delimitation of diatom species: a case study for the genusPinnularia(Bacillariophyta)

A polyphasic approach to the delimitation of diatom species: a case study for the genusPinnularia(Bacillariophyta)

Pantocsekiella, a new centric diatom genus based on morphological and genetic studies

Defining centric diatoms of most relevant phytoplankton functional groups in deep karst lakes

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