Morphological investigations of the frustule, perizonium and initial valves of the freshwater diatom Achnanthes crenulata Grunow (Bacillariophyceae)

Kensuke Toyoda, David M. Williams, Jiro Tanaka, Tamotsu Nagumo

Research output: Contribution to journalArticle

17 Citations (Scopus)


The present study clarifies the fine structure of the vegetative frustules, initial valves and perizonium of Achnanthes crenulata Grunow. The valves of the vegetative cell are distinctly linear-lanceolate with an undulate margin. The valve face is quite flat and in girdle view is smoothly curved as in species of Gephyria (Bacillariophyceae). However, the valve face of the initial cells is slightly rounded and does not have an undulate margin. Furthermore, the rapheless sternum is centrally positioned along the apical axis of the araphid initial valve. As this taxon develops from auxospore to initial valve, it forms only longitudinal perizonial bands; no transverse bands arise. The perizonium consists of three silicified bands: one large, central longitudinal plate and two bands that underlie this plate; these two bands are either open or closed. This taxon has several conspicuous structures compared to other marine species of Achnanthes, but the structure of the perizonium supports the position of A. crenulata within Achnanthes sensu stricto.

Original languageEnglish
Pages (from-to)173-182
Number of pages10
JournalPhycological Research
Issue number3
Publication statusPublished - 2006 Sep



  • Achnanthes crenulata
  • Achnanthes sensu stricto
  • Freshwater diatom
  • Initial cell
  • Monoraphid diatom
  • Perizonium

ASJC Scopus subject areas

  • Aquatic Science
  • Agricultural and Biological Sciences (miscellaneous)
  • Plant Science

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