Diatoms of North AmericaDiatoms of North America

Craticula subminuscula

(Manguin) C.E.Wetzel and Ector 2015

N Subminuscula Guide
  • Category
    Symmetric Biraphid
  • Length Range
    7.3-10.5 µm
  • Width Range
    3.3-5.0 µm
  • Striae in 10 µm
    20-28
  • Synonyms
    Eolimna subminuscula (Manguin) Gerd Moser, Lange-Bert. and Metzeltin 1998
  • Reported As
    Navicula luzonensis ()

Identification

Craticula subminuscula LM2 Craticula subminuscula LM5 Craticula subminuscula LM7 Craticula subminuscula LM1 Craticula subminuscula LM6 Craticula subminuscula LM4 Craticula subminuscula LM3
View image metadata
46562 Sem2 46562 Sem1

Description

Valves are elliptical-lanceolate, with acute ends, 3.3-5.0 µm wide, 7.3-10.5 µm long. The raphe is filiform, with slightly bent branches. The axial area is thickened, linear, only slightly widened in the center. Striae are radiate throughout, 20-28 in 10 µm, uniseriate. Areolae round or transapically elongated, often visible in LM .

Autecology

This taxon has been reported with light micrographs from the Great Plains, intermountain valleys, Wyoming Basin, Cascades, coastal streams, and Great Basin (Bahls 2023).

In the Great Lakes National Parks (Edlund et al. 2009, 2011, 2012, 2013), this taxon (as Navicula frugalis) is uncommon (1-5% abundance) in sediment core material from Isle Royale (Harvey, Richie, Ahmik lakes), Pictured Rocks (Beaver Lake), and Voyageurs (Ryan, Shoepack, Locator lakes).

This taxon is known to occur in lakes (Edlund et al. 2009, 2011, 2012, 2013), streams and rivers with cool alkaline waters of moderate conductivity and nutrient content (Bahls 2023). This taxon is eutraphentic.

Several research groups consider this taxon an indicator organism and published regional environmental optima and tolerances including:

Bahls (2023): Conductivity - 755 µS/cm, pH - 7.7, Temperature - 15.1°C, Total Nitrogen - 1.55 mg/L, Total Phosphorus - 159 µg/L.

Original Description

Valve eliptique lancéolée, à extrémités arrondie aiguës. Raphé droit; area axial très étroit, non élargi autour du nodule central. Stries radiales, un peu plus distantes dans la partie valvaire médiane, environ 25 en 10 µm, vers les extremites plus de 30. Long. 9-10 µm, larg. 4.5 µm. Pl. II, fig. 39. Cette espèce ne diffère de N. Lenzi Krasske (11: p. 556, Pl. XIX, fig. 11, 12) que par ses stries non ponctuées. Santa-Maria (XIV) R.: cuvette rocheuse à Potamogeton fluitans

  • Basionym
    Navicula subminuscula
  • Author
    Manguin 1942
  • Length Range
    9–10 µm
  • Width
    4.5 µm
  • Striae in 10µm
    25

Original Images

Nasubminusc Orig Illus
Nasubminusc Orig Descr
Original text and images reproduced with permission by Paris: Le Laboratoire de cryptogamie du Museum national d'histoire naturelle.

Citations & Links

Citations

Links

Updates

Apr 25, 2016 - Transfer from the genus Navicula to Craticula

This taxon appeared as Navicula subminuscula Manguin 1942 from May 2009 until April 2016. As of that date, the taxon appears as Craticula subminuscula (Manguin) Wetzel and Ector 2015.

Feb 05, 2026 - Addition of Autecology

From 2010 until 2026, the autecological information on this taxon page was limited. As of this update, information on ecology, biogeography, and environmental optima have been added. - Lane Allen and Mark Edlund

Cite This Page

Potapova, M., Edlund, M., Allen, L. (2009). Craticula subminuscula. In Diatoms of North America. Retrieved March 24, 2026, from https://diatoms.org/species/44529/craticula_subminscula

Responses

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