Valves are linear, with a slightly swollen center and cuneate ends. The axial area is narrow with an elliptic central area that is slightly wider on the primary side. Striae are radiate in the center and convergent at the apices. One longitudinal line marking internal openings of the alveoli and crossing the striae close to axial area is clearly visible under LM. The raphe is lateral with proximal raphe ends drop-shaped and deflected to the primary side. Terminal raphe fissures are hook-shaped.
Note that this taxon should be compared with Pinnularia latevittata var. domingensis Cleve, which was described from North America and also reported from the West Indies, Jamaica, San Domingo, and Ecuador (Cleve 1985). Pinnularia bihastata may have been reported as P. latevittata var. domingensis in the northeast (Camburn and Charles 2000).
This taxon has has been reported across a wide geographic range, but always in very rare abundance. The images shown here are from lakes in New Jersey, from collections at the Academy of Natural Sciences of Drexel University>
Kersey, M., Potapova, M. (2022). Pinnularia bihastata. In Diatoms of North America. Retrieved November 23, 2024, from https://diatoms.org/species/pinnularia-bihastata
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Pinnularia bihastata from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:
ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.