Taxonomy and diversity of a little-known diatom genus Simonsenia (Bacillariaceae) in the marine littoral: novel taxa from the Yellow Sea and the Gulf of Mexico
Open Access
- 9 July 2019
- journal article
- research article
- Published by Agentschap Plantentuin Meise in Plant Ecology and Evolution
- Vol. 152 (2), 248-261
- https://doi.org/10.5091/plecevo.2019.1614
Abstract
Background and aims – The diatom genus Simonsenia has been considered for some time a minor taxon, limited in its distribution to fresh and slightly brackish waters. Recently, knowledge of its diversity and geographic distribution has been enhanced with new species described from brackish-marine waters of the southern Iberian Peninsula and from inland freshwaters of South China, and here we report novel Simonsenia from fully marine waters. Methods – New isolates of Simonsenia species were obtained from marine waters, the littoral zone of the Korean Yellow Sea coast and the Gulf of Mexico in Corpus Christi (Texas), and documented in LM, SEM and with DNA sequence data (plastid-encoded rbcL and psbC). Phylogenetic trees of raphid diatoms were constructed to assess the relationships of the new species and of the genus as a whole. Key results and conclusions – Two novel species of Simonsenia (S. eileencoxiae and S. paucistriata) are described and a further putative taxon is characterized morphologically. The molecular phylogeny of the new Simonsenia species and previously sequenced species supports both the monophyly of the genus and its place within the Bacillariaceae. The Simonsenia clade clusters with clades composed of Cylindrotheca, Denticula and some Nitzschia spp. (including N. amphibia, N. frustulum, N. inconspicua). Hence Simonsenia is firmly positioned within the Bacillariaceae by molecular phylogenies, confirming its position within this group based on the possession of a canal raphe and its ultrastructure, and rejecting its classification within the Surirellaceae. Morphological data from the new Simonsenia species is typical for the genus, with a “simonsenioid” canal raphe type supported over the valve face with fenestral braces, alar canals connecting the canal raphe with the cell lumen, and the presence of fenestrae between the alar canals externally. Our results indicate unequivocally that the biogeography and the biodiversity of Simonsenia remain highly underestimated.Keywords
This publication has 16 references indexed in Scilit:
- Observations of two marine members of the genus Cymbellonitzschia (Bacillariophyta) from Tokyo Bay, Japan, with the description of the new species Cymbellonitzschia banzuensisPhycological Research, 2015
- Simonsenia aveniformis sp. nov. (Bacillariophyceae), molecular phylogeny and systematics of the genus and a new type of canal raphe systemScientific Reports, 2015
- New Insights into Plagiogrammaceae (Bacillariophyta) Based on Multigene Phylogenies and Morphological Characteristics with the Description of a New Genus and Three New SpeciesPLOS ONE, 2015
- Genetic and Physiological Diversity in the Diatom Nitzschia inconspicuaThe Journal of Eukaryotic Microbiology, 2015
- A Description of Biremis panamae sp. nov., a New Diatom Species from the Marine Littoral, with an Account of the Phylogenetic Position of Biremis D.G. Mann et E.J. Cox (Bacillariophyceae)PLOS ONE, 2014
- RAxML version 8: a tool for phylogenetic analysis and post-analysis of large phylogeniesBioinformatics, 2014
- Origin and Evolution of the Canal Raphe System in DiatomsProtist, 2011
- A preliminary multigene phylogeny of the diatoms (Bacillariophyta): challenges for future researchPlant Ecology and Evolution, 2010
- Using diatoms as quality indicators for a newly-formed urban lake and its catchmentEnvironmental Monitoring and Assessment, 2009
- Life history and systematics ofPetroneis(Bacillariophyta), with special reference to British watersEuropean Journal of Phycology, 2005