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


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.

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
Kim Byoung-Seok
Słowa kluczowe
Bacillariaceae; diatoms; Gulf of Mexico; Simonsenia; molecular phylogeny; morphology; new marine species; Yellow Sea
Słowa kluczowe
okrzemki; Zatoka Meksykańska; filogeneza molekularna; morfologia; nowe gatunki morskie; Morze Żółte
Witkowski Andrzej ORCID 0000-0003-1714-218X
Park Jong-Gyu
Li Chunlian ORCID 0000-0003-2279-7535
Trobajo Rosa
Mann David G.
Kim So-Yeon
Ashworth Matt
Bąk Małgorzata ORCID 0000-0001-6465-5047
Gastineau Romain ORCID 0000-0001-8661-5118
Typ zasobu
Identyfikator zasobu
DOI 10.5091/plecevo.2019.1614
Plant Ecology and Evolution, 2019, vol. 152 no. 2, pp. 248-261
Prawa autorskie
Publikacje pracowników US
Data udostępnienia25 maj 2023, 08:22:20
Data mod.25 maj 2023, 08:22:20
Aktywnych wyświetleń0