Gyrosigma
Gyrosigma is a genus of diatoms belonging to the family Pleurosigmataceae.
The genus has a cosmopolitan distribution.
Like other diatoms, Gyrosigma has a siliceous cell wall called a frustule. The frustule is composed of two sections called valves, with one valve fitting inside the other valve similar to the two halves of a Petri dish. Gyrosigma has valves with a central slit called a raphe, a structure that allows movement of these diatoms.
The valves of Gyrosigma are sigmoid in outline, as well as the raphe. Striations could be parallel or perpendicular to the raphe. This contrasts to a similar genus Pleurosigma, which has striations that lie diagonally to the raphe.
Species
Species:- Gyrosigma acuminatum
- Gyrosigma aestuarium
- Gyrosigma algoris
- Gyrosigma angulatum
- Gyrosigma apula
- Gyrosigma arcticum
- Gyrosigma attenuatum
- Gyrosigma baculum
- Gyrosigma baicalense
- Gyrosigma baikalensis
- Gyrosigma balticum
- Gyrosigma beaufortianum
- Gyrosigma bhusavalensis
- Gyrosigma bigibbum
- Gyrosigma caffra
- Gyrosigma calaritanum
- Gyrosigma cali
- Gyrosigma centropunctatum
- Gyrosigma coelophilum
- Gyrosigma compactum
- Gyrosigma constrictum
- Gyrosigma contortum
- Gyrosigma crassum
- Gyrosigma curtum
- Gyrosigma curvulum
- Gyrosigma cuspidata
- Gyrosigma diaphanum
- Gyrosigma diminutum
- Gyrosigma dissimilis
- Gyrosigma distortoides
- Gyrosigma diversitatum
- Gyrosigma dongzhaiense
- Gyrosigma dubia
- Gyrosigma dubium