Diatoms of North AmericaDiatoms of North America

Seminavis pusilla

(Grunow in A.Schmidt) E.J.Cox and G.Reid 2004

Navicymbula Pusilla Guide
  • Category
    Asymmetric Biraphid
  • Length Range
    16-33 µm
  • Width Range
    4.2-5.9 µm
  • Striae in 10 µm
    16-18 in the center valve, 19-20 at the ends
  • Synonyms
    Cymbella pusilla Grunow in Schmidt et al. 1875
    Navicymbula pusilla (Grunow) Krammer 2003

Identification

Navicymbula pusilla LM3 Navicymbula pusilla LM2 Navicymbula pusilla LM5 Navicymbula pusilla LM4 Navicymbula pusilla LM1
View image metadata
Navicymbula pusilla SEM1

Description

Valves are moderately dorsiventral with an arched dorsal margin. The ventral margin is flat, to slightly convex. The apices are rounded and not protracted. The axial area is narrow and widens in the valve center to form a small, lanceolate central area. The raphe is straight and weakly lateral. The external proximal ends and terminal fissures are hooked to the dorsal side. Striae are radiate in the valve center, becoming convergent at the ends. Areolae are lineolate and number 45-55 in 10 μm.

Autecology

Navicymbula pusilla is found in waters of high mineral content.

Original Description

  • Basionym
    Cymbella pusilla
  • Author
    Grunow in Schmidt et al. 1875

Original Images

Npusilla Orig Ill

Updates

May 19, 2026 - Transfer to Seminavis

From 10/13/2011 until 5/19/2026, this taxon appeared on this website as Navicymbula pusilla (Grunow in A.Schmidt) Krammer 2003. Publications (Cox and Reid 2004, Jeong and Lee 2024, Yilmaz et al. 2024) strongly support the species as aligning within Seminavis. The taxon now appears as Seminavis pusilla (Grunow) E.J.Cox and G.Reid 2004 and the Navicymbula genus page is closed - M. Edlund and M. Potapova

Cite This Page

Potapova, M. (2011). Seminavis pusilla. In Diatoms of North America. Retrieved May 22, 2026, from https://diatoms.org/species/47122/seminavis_pusilla

Responses

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