• Category
  • Length Range
    12-38 µm
  • Width Range
    4.5-6.6 µm
  • Striae in 10 µm
    16-20 near the center valve, 18-20 near the headpole, 16-20 near the footpole



Valves are clavate, with a broadly rounded to subrostrate headpole. The footpole is narrow and rounded. The axial area is narrow. The central area may be transverse or round and contains a single stigma. The raphe is slightly undulate and lateral. Distinct helictoglossae are present near both apices. The striae are radiate near the central area, becoming nearly parallel near the valve ends. One to two striae distal to the helictoglossae are radiate. Some striae near the central area are irregular and shortened. An apical pore field is present at the footpole.

In the SEM, the valve exterior is covered with round areolae, organized into multiseriate striae. The striae are biseriate, to arranged in a quincunx near the axial area. Externally, the proximal raphe ends are straight. At the headpole, the distal raphe fissure is straight; at the footpole, the distal raphe fissure extends over the mantle and bisects the apical pore field. The stigma has a simple, round external opening. The apical pore field is composed of small, round porelli. Internally, a reduced pseudoseptum is present at the headpole. The striae are located in depressed chambers; an axial plate and marginal lamella are both absent. The proximal raphe ends are recurved at the central nodule. The internal expression of the stigma is multichambered. Distally, the raphe terminates at distinct helictoglossae. The apical pore field has depressed chambers.

The specimens presented here represent the range of one population - large initial valves to valves smallest end of the size range.


Cells examined for this study were collected from 17 samples from five sites on Soda Butte Creek, Montana in 1972 and 1973. The stream is high elevation (2290 m.), moderate flow (2.5 cms mean flow), cold (0-10 °C), alkaline (pH 7.5-8.5), soft (26-74 mg/l CaCO3), well oxygenated (8.6-11 mg/l DO), and low to moderate nutrient content (0-0.05 mg/l NO3+NO2 and 0.02-0.06 µm/l PO4). Groundwater running through an abandoned gold and silver mine tailings pile leached reduced (Fe+2) iron into the stream 2.4 km above the sample point. Dilution from a relatively large tributary reduced the concentration of total iron at the sample point to 0.5-5.0 mg/l total Fe.

Soda  Butte And  Woody  Cr
Credit: Frank Pickett
Confluence of Soda Butte Creek and Woody Creek, Montana, where Gomphosinica geitleri grows in high abundance. Image taken August 2011.

Original Description

Valves are lanceolate to linear-lanceolate, with a capitate headpole and narrow footpole. The axial area is narrow, with a straight raphe. The central area is variable, orbicular to rectangular, and has a single isolated punctum. Striae number 13-16 in 10 µm and are radiate at the central area, strongly radiate at the footpole and nearly parallel at the headpole. Length 17-45 µm, breadth 5-8 µm.

  • Basionym
    Gomphoneis geitleri
  • Author
    Kociolek and Stoermer 1991
  • Length Range
    17-45 µm
  • Width
    5-8 µm
  • Striae in 10µm

Original Images

Gomphonema geitleri orig illus


Feb 25, 2024 - Transfer from Gomphoneis to Gomphosinica

This page originally appeared on Diatoms of the US as Gomphoneis geitleri Kociolek and Stoermer. In 2015, the genus Gomphonsinica was published. As of this date, the page was revised to show the transfer to Gomphonsinica. - S. Spaulding

Cite This Page

Pickett, F., Spaulding, S. (2011). Gomphosinica geitleri. In Diatoms of North America. Retrieved February 25, 2024, from https://diatoms.org/species/gomphosinica_geitleri


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