| 1. |
- Al-Handal, Adil Y, 1952, et al.
(författare)
-
Entomoneis annagodheisp. nov., a new marine diatom (Entomoneidaceae, Bacillariophyta) from the west coast of Sweden
- 2020
-
Ingår i: Diatom Research. - : Informa UK Limited. - 0269-249X .- 2159-8347. ; 35:3, s. 269-279
-
Tidskriftsartikel (refereegranskat)abstract
- The genusEntomoneisincludes diatoms with an elevated bilobate keel, a sigmoid raphe canal and numerous girdle bands. It is known to inhabit various environments, from freshwater to marine, both plankton and benthos. During a phytoplankton investigation in the Kungalv estuary on the west coast of Sweden, we observed numerous cells belonging toEntomoneis. Further morphological investigations performed with light and electron microscopy allowed us to describeEntomoneis annagodhei, sp. nov., with a unique set of morphological characters. Most importantly, a still undocumented character proved to be an oblique transapical fascia across the centre of the valve. Other distinctive features of this species are a pronounced raphe canal with dense raphe fibulae, very fine striation, resolvable only with electron microscopy, external lanceolate slit-like opening of the central nodule, and fine, linear to undulate external ridges running more or less parallel and adjacent to the raphe and valve margin. The morphological characters and morphometry are discussed in comparison with similar taxa. Our results contribute to the under-appreciated diversity ofEntomoneis, especially inhabiting the marine plankton.
|
|
| 2. |
- Plikk, Anna, 1982-, et al.
(författare)
-
Diatom assemblages from an Eemian palaeolake in Northern Europe with morphological observations of rare Aulacoseira sp. resting spores
- 2021
-
Ingår i: Diatom Research. - 0269-249X .- 2159-8347. ; 36:4, s. 313-321
-
Tidskriftsartikel (refereegranskat)abstract
- An overview of the diatom flora of the last interglacial (Eemian) lacustrine gyttja deposit at Sokli, northeastern Finland is presented together with descriptions including photomicrographs of resting spores similar to the Aulacoseira islandica-skvortzowii group, not found in recent material from Europe. Comparisons are made with literature data on similar taxa. The morphology of the resting spores (e.g., the number of striae and areolae in 10 mu m) links them to the A. islandica-skvortzowii group, but the lack of vegetative cells in the Sokli record makes the determination of true synonymy difficult. The presence of spores similar/related to the A. islandica-skvortzowii group in the Sokli Eemian palaeolake may reflect a more widespread distribution of this group in the past.
|
|
| 3. |
- Al-Handal, Adil Y, 1952, et al.
(författare)
-
Entomoneis grisslehamnensis, a New Diatom (Bacillariophyceae) from the Baltic Coast of Sweden with taxonomic and ecological notes on Entomoneis paludosa (W. Smith) Reimer
- 2023
-
Ingår i: Diatom Research. - 0269-249X. ; 38:1, s. 55-68
-
Tidskriftsartikel (refereegranskat)abstract
- The diatom genus Entomoneis includes species with panduriform frustules characterized by a bilobate, elevated keel, sigmoid raphe canal and numerous open, porous girdle bands. During a phytoplankton survey along the Baltic coast of Sweden, we observed numerous Entomoneis cells, some belonging to the well-known Entomoneis paludosa, while others remained unknown. Morphological and ultrastructural studies of the unknown species were performed with light microscopy (LM), scanning (SEM) and transmission (TEM) electron microscopy, and revealed a unique set of morphological characters. Live cells of Entomoneis grisslehamnensis sp. nov. contain one plate-like plastid and show various degrees of torsion about the apical axis. Microscopic features of cleaned frustules are discussed in comparison with similar species. Most importantly, every 2nd to 5th virga is strongly elevated, uniseriate striae are composed of quadrangular areolae with finely perforated hymenes; the winged keel with a discernible raphe canal is structurally strengthened by raphe fibulae with a flattened wing area, and the main part of the valve bulges towards the margins; striation is decussate on the wings and there is one row of raphe canal areolae at the central area. In addition to describing this new species of an underappreciated, yet cosmopolitan diatom genus, we contribute to the taxonomy of E. paludosa with LM, SEM and TEM details, some of which were not sufficiently noted in original descriptions or re-examination of type material and other specimens made by Dalu et al. [2015. A re-examination of the type material of Entomoneis paludosa (W. Smith) Reimer and its morphology and distribution in African waters. Fottea 15: 11-25] and Long et al. [2022. Ultrastructure of three species of Entomoneis (Bacillariophyta) from Lake Qinghai of China, with reference to the external areola occlusions.
|
|
| 4. |
- Al-Handal, Adil Y, 1952, et al.
(författare)
-
Navithidium gen. nov., a new monoraphid diatom (Bacillariophyceae) genus based on Achnanthes delicatissima Simonsen
- 2021
-
Ingår i: Diatom Research. - 0269-249X. ; 36:2, s. 133-141
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated the ultrastructure of Achnanthes delicatissima Simonsen in materials collected from the Swedish Baltic coast. Valve structure differs markedly from that of Achnanthes sensu lato, particularly in the absence of cribrate areolae which separates Achnanthes from all other members of the family Achnanthaceae. Comparing this species with those recently described achnanthoid genera, such as Scalariella Riaux-Gobin & Witkowski and Madinithidium Witkowski, Desrosiers & Riaux-Gobin revealed morphological differences that warrant the erection of a new genus, Navithidium. Owing to the small size of the frustules, it is difficult to identify Navithidium delicatissima in light microscopy due to similarities with some closely related taxa like Achnanthidium pseudochamaepinnularia (which is here transferred to Navithidium). A comparison with related genera is provided and discussed. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
|
|
