• Category
  • Length Range
    8.2-35.5 µm
  • Width Range
    5.6-14.0 µm
  • Striae in 10 µm



Valves are lanceolate-elliptical, with rounded to cuneate ends. Costae number 1-3 in 10 µm. Striae are radiate. Areolae may, or may not, be visible in LM on larger specimens. Costae are heavily silicified. Each girdle band contains a septum, which alternates between poles in adjacent copulae. A single transversely oriented rimoportula is located between the first and second costae toward one end, near the sternum. Copulae in girdle view are relatively linear and only slightly overlap.


Tetracyclus hinziae has been documented in several catchments in the Cascade Mountain Range, from shaded 1st order streams such as Mason Creek and Van Trump Creek, to wider, unshaded 3rd order rivers such as the South Fork Snoqualmie River. Tetracyclus hinziae is abundant in mossy splash zones and co-occurs with common araphids, including T. glans, Tabellaria flocculosa, Meridion circulare and Diatoma mesodon. It is likely often misidentified as the last of these (Bishop and Spaulding 2015).

Live Plate
Credit: Sarah Spaulding
Living cells of T. hinziae showing multiple chloroplasts. Scale bar is equal to 20 µm.
Mason  Creek Aerophilic Habitat
Credit: Ian Bishop
Mason Creek, Washington

Original Description

  • Author
    Bishop and Spaulding 2015
  • Length Range
    8.2-35.5 µm
  • Width
    5.6-14.0 µm
  • Striae in 10µm

Original Images

T Hinziae Orig Desc Image
T Hinziae Orig Desc Text

Cite This Page

Bishop, I. (2014). Tetracyclus hinziae. In Diatoms of North America. Retrieved May 28, 2024, from https://diatoms.org/species/tetracyclus_hinziae


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Tetracyclus hinziae 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.