Lacustriella Guide
Credit: Mark Edlund, David Burge
  1. Valves lanceolate to elliptic
  2. Apices acute
  3. Terminal raphe fissures oppositely curved
  4. Striae end at the face-mantle junction in an elongate areola

Species of Lacustriella are characterized by large valves with acute apices, uniseriate striae and terminal raphe fissures that are oppositely deflected. The valve outline ranges from lanceolate to elliptic. The raphe fissures continue onto the mantle. Striae are uniseriate and radiate, and terminate with an elongate areola. Striae do not continue on to the mantle.

Lacustriella contains several taxa formerly placed in Cavinula and Navicula sensu lato. The genus was separated based on large valves, striae termination, and distal raphe ends. While the generitype is only reported from Lake Baikal, Russia, the species L. lacustris is widely distributed. It has been reported from North America (Bahls 2017, Patrick and Reimer 1966, Stoermer 1980, Foged 1981), Europe and Asia.