• Category
  • Length Range
    77.6-86.9 µm
  • Width Range
    14.7-15.4 µm
  • Striae in 10 µm
    9-9.5 in the valve center, 11-12 at the ends



Valves are lanceolate with acute, protracted apices. The axial area is linear-lanceolate. The central area is transversely elliptic. The raphe is moderately lateral, with dilated external proximal raphe ends. Striae are radiate throughout. A few central striae are more widely spaced and more broad than other striae. The areolae number 26-32 in 10 μm.

Patrick and Reimer (1966) noted a report of N. hasta in North America by "Boyer and Hohn". We were unable to find records at ANSP by Matthew Hohn. However, Boyer (1916) reported N. hasta from a fossil deposit (likely Pliocene or Pleistocene) near Philadelphia. We confirmed these specimens at ANSP (Boyer 658). In the same publication, Boyer described a new variety, N. hasta var. punctata Boyer from Greenwich Point, Philadelphia. The site is noted for tidal influence and an abundance of brackish water taxa. Navicula hasta var. punctata was described as similar to the nominate variety, but with "striae in the middle distinctly punctate and reaching the median line". However, our exhaustive search of ANSP samples from Greenwich Point, including Mahoney and Reimer (1997) did not uncover specimens that match Boyer's description of N. hasta var. punctata.

Levkov et al. (2008) concluded that ‘hasta-like’ specimens are present in North America, they are not perfectly associated with the N. hasta of the type. For example, populations from Massachusetts and Arkansas have slightly finer striae than Pantocsek’s material (6.5-7 striae per 10 µm). North American specimens are probably more closely related to the N. hasta sensu lato populations from the ancient lakes in Japan and populations from the Baikal Rift Zone lakes. Thus, it is clear that the group is in need of taxonomic revision. The images presented here are as N. hasta sensu lato.

Images of specimens from several of these reports and collections are shown in the citations. The breadth of morphological variability in the Navicula hasta group needs further work including careful analysis of our North American populations.


Specimens of Navicula hasta illustrated here are from the Green River in Massachusetts and the Buffalo River in Arkansas. Other North American reports of Navicula hasta include specimens illustrated from the Great Smoky Mountains (Lowe and Kociolek 1984) and inland lakes (Douglas Lake, Cheboygan Co., Andresen and Stoermer 1978, MICH-Andresen SFB-5-18 [Fig. 3], SFB-5-20 [Fig. 1]; Grand Sable Lake, Pictured Rocks National Lakeshore, Edlund et al. 2011, SMM-12262a [Figs 4, 5]) and streams (Maple River, CAS-EFS 1175 [Fig. 2]) in Michigan. Other reports include blue clay fossil deposits from Pennsylvania (Boyer 1916, ANSP Boyer 658 [Fig. 6]), the Delaware River (Boyer 1927; no illustrations), the Laurentian Great Lakes (Stoermer and Kreis 1978, Stoermer et al. 1999, no illustrations), and the Savannah River in Allendale Co., South Carolina (ANSP GC-46383a [Fig. 7]). Images of specimens from several of these reports/collections are shown below.

Figs 1–7. Other North American populations of Navicula hasta from Michigan (Figs 1-5), Boyer 658 material from Pennsylvania, fossil (Fig. 6), and South Carolina (Fig. 7).

DONA Autecology Figs1 7

Original Description

Navicula hasta Pant. nov. spec. Valvis elongato lanceolatis 63-76 µ, longis, 14-18 µ latis, cum polis productis obtusis. Rhaphe directa, ab area axillari longitudinali sat dilatata cincta. Striae validae radiantes striolatae 8— 10 in 10 µ, ad centrum longiores et breviores. In stratis tertiariis aquae dulcis ad Bibarczfalva, Bodos et Köpecz in Transilvania. Icon: Beitrg. III., tab. 5., fig. 74 tab. 14., fig. 213.

  • Author
    Pant. 1892
  • Length Range
    63-76 µm
  • Width
    14-18 µm
  • Striae in 10µm

Original Images

N Hasta  Orig Ill1
N Hasta  Orig Ill2
N Hasta  Orig Descr

Citations & Links



  • Index Nominum Algarum
  • North American Diatom Ecological Database
    NADED ID: 46533

Cite This Page

Potapova, M., Edlund, M. (2021). Navicula hasta. In Diatoms of North America. Retrieved July 13, 2024, from https://diatoms.org/species/navicula_hasta


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