• Valve is organized around a line (bilateral symmetry)
  • Valves symmetrical to transapical axis, asymmetrical to apical axis
  • Raphid system well developed, and enclosed within a canal

Note: The specimen(s) pictured to the right are not from Antarctica, excepting Naviculoid example.

Taxon Name Basionym synonyms ID
Rhopalodia rupestris Rhopalodia gibberula var. rupestris 251