Lange-Bertalot and Cantonati 2010      Category: Symmetrical biraphid
TYPE SPECIES: Neidiomorpha binodiformis (Krammer) Cantonati, Lange-Bertalot and Angeli




CLASS: Bacillariophyceae
  ORDER: Naviculales
    FAMILY: Neidiaceae

  1. Shallow caves present
  2. Central valve margin constricted
  3. Proximal raphe ends straight

Neidiomorpha is a recently erected genus closely related to Neidium. In Neidiomorpha, the marginal canals are greatly reduced and are termed “shallow caves”. Valves are linear, with central margins constricted. The apices are rostrate. The proximal raphe ends are simple pores, slightly deflected to the primary side. Two plastids are present.

While species in the genus Neidium possess distinct canals at the valve margin, the canals are absent in Neidiomorpha. Also in contrast to Neidium, Neidiomorpha lacks longitudinal hyaline areas and bifurcate distal raphe fissures. The genus Neidiopsis also lacks marginal longitudinal canals, but is characterized by small areolae in double rows next to the axial area.

Neidiomorpha includes the species N. binodiformis and N. binodis. Neidiomorpha binodiformis is typical of moderate conductivity waters, while N. binodis is characteristic of carbonate, high conductivity and slightly saline waters.

Cite This Page:
Spaulding, S. (2013). Neidiomorpha. In Diatoms of the United States. Retrieved April 24, 2018, from

Contributor: Sarah Spaulding - April 2013