&lt;em&gt;Nitzschia imae&lt;/em&gt; sp. nov. (Bacillariophyta, Nitzschiaceae) from Iceland, with a redescription of &lt;em&gt;Hannaea arcus&lt;/em&gt; var. &lt;em&gt;linearis&lt;/em&gt;

Irene Álvarez-Blanco,Saúl Blanco

doi:10.3989/ajbm.2358

Abstract

From field-collected samples, two Icelandic diatom species were studied under light and electron microscopy, resulting in a newly described species and an emended description with a nomenclatural status change. A discussion on the morphological features of these taxa and their taxonomic affinities with related species is presented. Nitzschia imae is described from Blue Lagoon, south-west Iceland. The main diagnostic criteria include the presence of two differences morphotypes, one with obtusely rounded apices and the other with slightly asymmetrical valve outline and broadly rounded apices. Additionally, we propose an emended description for Hannaea arcus var. linearis since there is no concordance between morphometric features in the protologue and the type illustration.

Highlights

The freshwater diatom flora of Iceland was initially studied first by Hansen (1872) and Ostenfeld (1904), but it was not until 1918 when the first comprehensive flora was given by E. Østrup (1918), he studied 572 samples collected from a large number of sites in the main part of the country and enumerated 468 taxa, a remarkably large number for that time
The present paper studies the diatom flora from two aquatic ecosystems of Iceland, the Blue Lagoon, and the Laxá stream, both located in the south-west of the country
We first report a new taxon found at the Blue Lagoon belonging to genus Nitzschia, analyzing the valvar ultrastructure through light and scanning electron microscopy

Summary

INTRODUCTION

The freshwater diatom flora of Iceland was initially studied first by Hansen (1872) and Ostenfeld (1904), but it was not until 1918 when the first comprehensive flora was given by E. Østrup (1918), he studied 572 samples collected from a large number of sites in the main part of the country and enumerated 468 taxa, a remarkably large number for that time. The freshwater diatom flora of Iceland was initially studied first by Hansen (1872) and Ostenfeld (1904), but it was not until 1918 when the first comprehensive flora was given by E. The present paper studies the diatom flora from two aquatic ecosystems of Iceland, the Blue Lagoon (a shallow geothermal lake), and the Laxá stream, both located in the south-west of the country. We first report a new taxon found at the Blue Lagoon belonging to genus Nitzschia, analyzing the valvar ultrastructure through light and scanning electron microscopy. This species is compared with some closely related species. A nomenclatural change for this taxon is proposed based on differences existing between this and the nominal variety

MATERIAL AND METHODS

Methods

RESULTS AND DISCUSSION