• Category
  • Length Range
    135-261 µm
  • Width Range
    65-100 µm
  • Striae in 10 µm
  • Reported As
    Surirella davidsonii (Metzeltin and Lange-Bertalot 1998, pl. 214, figs 1, 2.)
    Surirella davidsonii (Rumrich et al. 2000, pl. 189, figs 2, 3.)



Cells are large and solitary. Valves are heteropolar; the head pole is broadly rounded, while the foot pole is cuneately rounded. The valves appear flat in LM, except for a depression at the head pole that appears out of focus. Two spines are occasionally visible at both sides of the depression. The areolae and striae are too delicate to be visible under LM. The raphe is positioned within a marginal canal, raised onto a keel and supported by alar canals. The fibula density is 28-31 in 100 µm. The costae are short.

The keel appears shallow, but in SEM alar canals are visible. Externally, the raphe is discontinuous at the head pole. Internally, the raphe is continuous at the head pole and discontinuous at the foot pole. Note that fenestrae are absent, which may be due to the closely spaced alar canals.

Note that Surirella guatimalensis Ehrenb. 1854 has priority over S. cardinalis Kitton 1868 and S. davidsonii A. Schmidt 1875. This taxon was identified as S. davidsonii A. Schmidt by Metzeltin and Lange-Bertalot (1998) and Rumrich et al. (2000).


Iconella guatimalensis is found occasionally in lakes of the Northeastern US. It is not a particularly rare species, but is commonly missed in routine counts of fixed number of valves, as are many other large-celled diatoms.

Collections from La Selva Biological Station, Costa Rica (Site CR4, Rebecca Bixby) included samples with abundant cells here shown in SEM.

Original Description

  • Basionym
    Surirella guatimalensis
  • Author
    Ehrenb. 1854

Original Images

Suri Guatimalensis Orig Ill
Suri G Uatimalensis Orig Descr

Citations & Links



Cite This Page

Potapova, M. (2022). Iconella guatimalensis. In Diatoms of North America. Retrieved October 03, 2023, from https://diatoms.org/species/iconella-guatimalensis


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