Guide to Karayevia
Credit: Marina Potapova
- Rapheless valve with nearly parallel striae
- Raphe valve with radial striae
- External distal raphe fissures curved to one side
- Internal expression of areolae occluded
The valves of Karayevia are elliptic to lanceolate with rostrate to capitate ends. The rapheless valve possesses striae that are nearly parallel, composed of circular areolae. The raphe valve possesses radial striae, composed of transapically elongate areolae. Externally, the distal raphe fissures curve to the same side. Internally, the areolae are occluded. Cells grow attached to sand grains, with many species preferring alkaline waters. This genus contains species related to Achnanthes clevei Grunow in Cleve et Grunow.
The original description of the genus, as Kolbesia, was invalid because the type was not designated (Fourtanier and Kociolek 1999) Round (1998) later validily published the genus. The type of Kolbesia and its members have been transfered to Karayevia.