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The genus Pseudo-nitzschia (Bacillariophyceae) in a temperate estuary with description of two new species: Pseudo-nitzschia plurisecta sp. nov. and Pseudo-nitzschia abrensis sp. nov.
Author(s) -
Orive Emma,
PérezAicua Lara,
David Helena,
GarcíaEtxebarria Koldo,
LazaMartínez Aitor,
Seoane Sergio,
Miguel Irati
Publication year - 2013
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/jpy.12130
Subject(s) - biology , nitzschia , diatom , botany , taxonomy (biology) , phylogenetic tree , taxon , clade , genus , zoology , ecology , phytoplankton , gene , genetics , nutrient
The genus P seudo‐nitzschia contains potentially toxic species of problematic taxonomy, making it one of the most intensively studied diatom genera. The study of 35 clonal strains isolated from the B ilbao estuary, an area that experiences recurrent blooms of P seudo‐nitzschia , revealed the presence of two new species, P . abrensis and P . plurisecta , differing from their congeners in both morphology and gene sequence. The morphological features were analyzed by LM and EM , whereas molecular analyses were based on the internal transcribed spacer ( ITS ) and large subunit ( LSU ) regions of the r DNA . P . plurisecta appears closely related to P . cuspidata / P . pseudodelicatissima in the phylogenetic tree, whereas P . abrensis forms a moderately supported clade with P . heimii/ P . subpacifica and P . caciantha/ P . circumpora . Comparison of the secondary structure of ITS 2 regions reveals marked differences in the most highly conserved regions among related taxa. Morphologically, the new species differ from their closest congeners in the arrangement of the poroid sectors and the density of valve striae and fibulae. The two species share similar pigment composition, and belong to the group of P seudo‐nitzschia species containing only chlorophyll c 2 and c 3 .