科研之友
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摘要
The large-celled Navicula petrovii sp. nov., has distinct amphoroid symmetry and is described from recent sediments of the Black Sea coast of Crimea. In the past this species was identified by Peragallo from the Mediterrenean Sea as Amphora scabriuscula and later transferred by Mereschkowsky to Navicula. Our LM and SEM studies revealed that N. petrovii sp. nov. differs in terms of valve ultrastructure and symmetry from Amphora, and it shares features with several naviculoid genera. It has features similar to Navicula, including oblique opening of raphe internal fissure, and striae composed of lineolate areolae. Dorsiventral valves, reduced girdle bands at the ventral side are features shared with Seminavis, while features of a high mantle, presence of striae forming areolae clearly set off at the apices are shared with Hippodonta. Navicula petrovii sp. nov. resembles Trachyneis in terms of plastids in girdle view, LM appearance of striae, high, open girdle bands, external apical raphe endings and internal appearance of striae located in relatively deep, but open alveoli. Based on information available on plastid structure and valve ultrastructure we discuss the phylogenetic position of this enigmatic species and suggest it fits sufficiently within the circumscription of Navicula sensu stricto. The dorsiventral nature of the valve is discussed relative to other species with similar morphology, and the possible environmental conditions that might account for this development. Navicula petrovii sp. nov. is compared to Amphora scabriuscula which originally has been described from the Macassar Straits in the western Pacific Ocean. We have shown that these two taxa are different and that identifications of A. scabriuscula from the Mediterranean and Black Sea are erroneous. Hence further transfer of the latter species to Navicula by Mereschkovsky is not justified.
- 出版日期2014
