High diversity of Pseudo‐nitzschia along the northern coast of Sarawak (Malaysian Borneo), with descriptions of P. bipertita sp. nov. and P. limii sp. nov. (Bacillariophyceae)

Abstract

Forty-eight isolates of Pseudo-nitzschia species were established from the Miri coast of Sarawak (Malaysian Borneo) and underwent TEM observation and molecular characterization. Ten species were found: P. abrensis, P. batesiana, P. fukuyoi, P. kodamae, P. lundholmiae, P. multistriata, P. pungens, P. subfraudulenta, as well as two additional new morphotypes, herein designated as P. bipertita sp. nov. and P. limii sp. nov. This is the first report of P. abrensis, P. batesiana, P. kodamae, P. fukuyoi, and P. lundholmiae in coastal waters of Malaysian Borneo. Pseudo-nitzschia bipertita differs from its congeners by the number of sectors that divide the poroids, densities of band striae, and its cingular band structure. Pseudo-nitzschia limii, a pseudo-cryptic species in the P. pseudodelicatissima complex sensu lato, is distinct by having wider proximal and distal mantles, a higher number of striae, and greater poroid height in the striae of the valvocopula. The species were further supported by the phylogenetic reconstructions of the nuclear-encoded large subunit ribosomal gene and the second internal transcribed spacer. Phylogenetically, P. bipertita clustered with its sister taxa (P. subpacifica + P. heimii); P. limii appears as a sister taxon to P. kodamae and P. hasleana in the ITS2 tree. Pairwise comparison of ITS2 transcripts with its closest relatives revealed the presence of both hemi- and compensatory base changes. Toxicity analysis showed detectable levels of domoic acid in P. abrensis, P. batesiana, P. lundholmiae, and P. subfraudulenta, but both new species tested below the detection limit.

Phylogeny and species delineation in the marine diatomPseudo‐nitzschia(Bacillariophyta) usingcox1,LSU, andITS2rRNAgenes: A perspective in character evolution

“…The phylogenetic relationship between the sister taxa of P. subpacifica / P. heimii (not included in the present study), as seen in Teng et al. () and Orive et al. (), warrants further verification, especially regarding species identity.…”

“…(), and Teng et al. (, , ). Another nine strains of Pseudo‐nitzschia (belonging to P. batesiana ; P. bipertita ; P. brasiliana ; P. cuspidata ; and P. fukuyoi ) were newly established, isolated from the Miri and Bintulu coasts of Sarawak (Malaysian Borneo), the Port Dickson coast of Negeri Sembilan (Peninsular Malaysia), and St. John's Island (Singapore).…”

“…, , Teng et al. , , ). Meanwhile, the cytochrome c oxidase subunit 1 gene ( cox1 ) and SSU have only been used in a few studies (Lundholm et al.…”

Species occurrence of the potentially toxigenic diatom genus Pseudo-nitzschia and the associated neurotoxin domoic acid in the Argentine Sea

“…The number of described Pseudo-nitzschia species, as well as the number of confirmed DA producers in culture, has notably increased in the last few years (e.g., Lelong et al, 2012;Lim et al, 2013;Orive et al, 2013;Teng et al, 2016;Percopo et al, 2016). By contrast, the worldwide distribution of most of these species and their toxicity in natural populations is still poorly known.…”

An attempt to semi-quantify potentially toxic diatoms of the genus <i>Pseudo-nitzschia</i> in Tokyo Bay, Japan by using massively parallel sequencing technology

“…Using the study carried out by Yap-Dejeto et al (2010) as a basis for speculation, OTUs 6 and 12 may have represented P. pseudodelicatissima and P. delicatissima, respectively (Table 1). It is likely we would have been able to identify all species if, in addition to the MPS procedure carried out, we had also collected Pseudo-nitzschia cells (>100 cells) using a capillary pipette once every three or four samples, and obtained LSU including ITS sequences using subcloning techniques carried out on the pipetted cells (Nagai et al 2008, Teng et al 2016. Therefore, time-series monitoring of Pseudo-nitzschia using MPS-based techniques alongside the sub-cloning of known Pseudo-nitzschia cells may prove useful, especially in regions where highly toxic and non-toxic Pseudo-nitzschia species co-appear.…”