PreprintArticleVersion 1Preserved in Portico This version is not peer-reviewed
The Perizonium Ultrastructure, Divided Apical Pore Fields, Various Pore Occlusions and Visible Intermissio in Cymbella (Bacillariophyceae) with Descriptions of Four New Species
Yang, B.; Liu, B.; Blanco, S.; Rioual, P. The Perizonium Ultrastructure, Divided Apical Pore Fields, Various Pore Occlusions and Visible Intermissio of Cymbella (Bacillariophyceae) with Descriptions of Four New Species. Plants2024, 13, 1851.
Yang, B.; Liu, B.; Blanco, S.; Rioual, P. The Perizonium Ultrastructure, Divided Apical Pore Fields, Various Pore Occlusions and Visible Intermissio of Cymbella (Bacillariophyceae) with Descriptions of Four New Species. Plants 2024, 13, 1851.
Yang, B.; Liu, B.; Blanco, S.; Rioual, P. The Perizonium Ultrastructure, Divided Apical Pore Fields, Various Pore Occlusions and Visible Intermissio of Cymbella (Bacillariophyceae) with Descriptions of Four New Species. Plants2024, 13, 1851.
Yang, B.; Liu, B.; Blanco, S.; Rioual, P. The Perizonium Ultrastructure, Divided Apical Pore Fields, Various Pore Occlusions and Visible Intermissio of Cymbella (Bacillariophyceae) with Descriptions of Four New Species. Plants 2024, 13, 1851.
Abstract
The initial valves of two Cymbella species are observed under the scanning electron microscope and the perizonium ultrastructure of Cymbella is revealed for the first time. The perizonium is composed of alternate nodes and internodes and lacks transverse perizonium bands. Four new species, Cymbella apiculatophora sp. nov., C. hunanensis sp. nov., C. juglandis sp. nov. and C. menyuanensis sp. nov., are described using light and scanning electron microscope from epilithon samples collected in rivers from Hunan and Qinghai Provinces, China. Cymbella menyuanensis is a typical Cymbella species that closely resembles species in the group around C. cymbiformis Agardh, the lectotype species of the genus. Cymbella apiculatophora is similar to C. sinensis Metzeltin & Krammer while Cymbella hunanensis is closer to the C. hustedtii Krasske group. The last species, C. juglandis, has a cymbelloid valve outline, obscured intermissio, internal occlusions of areolae, dorsally deflected distal raphe fissures, and a divided APF at each apex, and does not appear to belong to any group. In addition, new observations on C. cf. excisiformis Krammer and C. hustedtii are reported. The current concept of the genus Cymbella does not represent a monophyletic group as shown by molecular phylogenetic analyses. However, these analyses are still at the preliminary stage and are not yet sufficient to support a complete revision of the genus. Thus, although extremely diverse ultrastructural features are observed in the six Cymbella species investigated in this paper, we prefer to keep them within Cymbella at this moment for the sake of nomenclatural stability.
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
