• Category
  • Length Range
    55.4-73.7 µm
  • Width Range
    10.9-12.9 µm
  • Striae in 10 µm



Valves are linear-lanceolate, with slightly convex sides. The apices are acutely rounded. The axial area is narrow, with a rhombic central region. The central area is distinct, with an acutely angled, transverse fascia. The raphe is lateral, with tear drop shaped proximal ends and question mark shaped terminal fissures. Striae are strongly radiate in the center, becoming convergent toward the apices.

We examined the type slide (ANSP GC57557) and noted that specimens were shorter than stated in the original description.

Some varieties of Pinnularia brebissonii may be difficult to separate from P. wisconsinensis. In particular, the taxon P. brebissonii var. acuta should be examined as it may be conspecific with P. wisconsinensis (and have priority of publication).


Despite its name, Pinnularia wisconsinensis was described from Merriam Lake, New York. We documented it from other lakes in New York, including Deep Lake and Grass Pond.

Original Description

Pinnularia wisconsinensis Camburn & Charles, sp. nov. (Pl. 28, figs 5-7)

Valva linearis-lanceolata marginibus paulo convexis extremitatibus subrostratis interdum area asialii angusta versus aream centralem latiorem area centrali rhobica fascia transversa acutangulari. Raphe obliqua pro parte maxima apicibus distalibus amplis falcatis apicibus proximalibus bulbosis et flexis unilateralibus. Striae ad centrum valde radiatae versus extremitates valde convergens; 9-11 in 10 µm. Longitudo: 60-72 µm. Latitudo: 11-13 µm.
Holotypus: A.-G.C. 57557, in collectione generali diatomarum Academiae Scientarium Naturalium Philadelphiae.

Valve linear-lanceolate, sides slightly convex; ends may be subtly subrostrate. Axial area narrow, widening into a rhomboidal central area with an acute-angled transverse fascia. Raphe mostly oblique, polar terminals large and sickle-shaped, central terminals bulbous and slightly bent unilaterally. Striae strongly radiate toward the center of the valve to strongly convergent at the ends. Striae changeover point midway. Striae, 9-11 in 10 µm. Length, 60-72 µm. Breadth, 11-13 µm.
HOLOTYPE A.-G.C. 57557. In general diatom collection, Academy of Natural Sciences of Philadelphia.

Type locality. U.S.A., New York, Herkimer County, Merriam Lake, 43°51'22" N, 74°50'45" W, Core 2, 10.0-20.5 cm, August 6, 1982.

Pinnularia wisconsinensis is characterized by an acute-angled transverse fascia. A SEM of this taxon may be seen in Camburn et al. (1986, Pl. 52, Fig. 237).

  • Author
    Camburn and Charles 2000
  • Length Range
    60-72 µm
  • Width
    11-13 µm
  • Striae in 10µm

Original Images

Pin wisconsinesis org img
Pin wisconsinesis org descp

Cite This Page

Aycock, L. (2022). Pinnularia wisconsinensis. In Diatoms of North America. Retrieved May 20, 2024, from https://diatoms.org/species/pinnularia-wisconsinensis


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