New Insights into Plagiogrammaceae (Bacillariophyta) Based on Multigene Phylogenies and Morphological Characteristics with the Description of a New Genus and Three New Species

Abstract

Plagiogrammaceae, a poorly described family of diatoms, are common inhabitants of the shallow marine littoral zone, occurring either in the sediments or as epiphytes. Previous molecular phylogenies of the Plagiogrammaceae were inferred but included only up to six genera: Plagiogramma, Dimeregramma, Neofragilaria, Talaroneis, Psammogramma and Psammoneis. In this paper, we describe a new plagiogrammoid genus, Orizaformis, obtained from Bohai Sea (China) and present molecular phylogenies of the family based on three and four genes (nuclear-encoded large and small subunit ribosomal RNAs and chloroplast-encoded rbcL and psbC). Also included in the new phylogenies is Glyphodesmis. The phylogenies suggest that the Plagiogrammaceae is composed of two major clades: one consisting of Talaroneis, Orizaformis and Psammoneis, and the second of Glyphodesmis, Psammogramma, Neofragilaria, Dimeregramma and Plagiogramma. In addition, we describe three new species within established genera: Psammoneis obaidii, which was collected from the Red Sea, Saudi Arabia; and Neofragilaria stilus and Talaroneis biacutifrons from the Mozambique Channel, Indian Ocean, and illustrate two new combination taxa: Neofragilaria anomala and Neofragilaria lineata. Our observations suggest that the biodiversity of the family is strongly needed to be researched, and the phylogenetic analyses provide a useful framework for future studies of Plagiogrammaceae.

Multigene Assessment of Biodiversity of Diatom(Bacillariophyceae) Assemblages from the Littoral Zone of the Bohai and Yellow Seas in Yantai Region of Northeast China with some Remarks on Ubiquitous Taxa

“…Although there are numerous examples of studies where particular taxonomic or phylogenetic issues regarding marine benthic diatoms have been addressed, these are typically restricted to smaller, more tractable clades and genera with limited geographic sampling ( e. g. Ashworthet al, 2012Ashworthet al, , 2013Kooistra et al, 2004, Sato et al, 2008a . Understanding the dispersal and genetic variability of diatom species is only possible with a diverse range of DNA sampling from across the globe, which can include severely undersampled but geographically vast sites such as coastal China ( this study ) , the psychrophilic diatoms of the Arctic and Antarctic by Choi et al (2008) or tropical coral reefs ( Ashworth et al, 2012,;Lobban, et al, 2011;Li et al, 2015) . The study of Choi et al used SSU and rbcL and morphology ( LM and SEM ) to document the phylogenetic relationships between taxa inhabiting sea ice in the high latitudes of both hemispheres.…”

“…The protocol for DNA extraction and PCR amplification follows Li et al (2015) . Depending on cell density, several milliliters of cell suspension from an exponentially growing culture were centrifuged for 15 min at 8,000 rpm to create a cell pellet.…”

“…The following clones were isolated from CD5: Surirella cf. fastuosa ( Ehrenberg) Kützing ( SZCZCH189, Hendey, 1964 ) , a very small unidentified Navicula sensu stricto species ( SZCZCH965) , Orizaformis holarctica Witkowski, Li & Ashworth ( SZCZCH111, Li et al, 2015, Figure 3j) and Tryblionella sp. ( SZCZCH97, Figure 3i; 7) , which we describe here as a new species: T. gaoana Witkowski & Li sp.…”

Ultrastructural and molecular characterization of diversity among small araphid diatoms all lacking rimoportulae. I. Five new genera, eight new species

“…, Li et al. ). Williams and Kociolek () encouraged the rejection of the paraphyletic group and Kociolek and Williams () called for revisionary works on all levels of diatom groups based on monophyly.…”

“…, Lobban and Navarro , Lobban and Ashworth ,b, Li et al. ). Additional diversity is likely hidden within broadly defined araphid genera such as Synedra Ehrenberg and Fragilaria Lyngbye.…”