• Category
  • Length Range
    15–54 µm
  • Width Range
    2.0–2.6 µm
  • Striae in 10 µm
  • Reported As
    Eunotia incisa (Camburn and Charles 2000, pg. 66, Pl. 13, Fig. 9)
    Eunotia incisa "narrow form" (Siver et al. 2005, p. 80, Pl. 26, Fig. 12)
    Eunotia sp. aff. incisa (Lange-Bertalot et al. 2011, pg. 336, Pl. 36, Fig. 39)



Valves are narrow and linear, with straight ventral margin and slightly arcuate dorsal margin. Valves are widest in the center and gradually tapering to the apices. The apices are acute and usually slightly bent to the ventral side. Valve length to width ratio is 7–24. The raphe is relatively long (5–7 μm) and situated mostly on the valve mantle. The helictoglossa at each apex is expanded, into an internal costa across the valve apex and penetrated by a single stria. Costae are clearly visible in LM. One large rimoportula per valve is present, placed centrally at the valve apex, occasionally visible in LM. Striae are parallel throughout the valve becoming slightly radiate at the apices. Areolae are circular and externally occluded, 45–55 in 10 μm. In girdle view, frustules are slender and (3.2–5.2 μm wide) rectangular with rounded edges.


Eunotia novaeangliae was described from Acadia National Park, Maine (Veselá & Johansen 2014), where it occured in the benthos of acidic and oligotrophic lakes and streams (pH 4.6–5.1, cond. 23–110 μS). It was also collected (although mis- or un-identified) from Big Moose Lake in the Adirondack Mountains region, New York (Camburn & Charles 2000), from lakes on Cape Cod Peninsula, Massachusetts (Siver et al. 2005), and from Canada (Lange-Bertalot et al. 2011). This species is likely more widely distributed on the east coast of North America, especially New England and southeastern Canada.

Original Description

In girdle view frustules are rounded-rectangular, slender, and 3.2–5.2 μm wide (Figs 35–39). Valves are linear with straight ventral margin and slightly arcuate dorsal margin, widest in the center and gradually tapering toward the ends throughout the whole length of the valve, with ends often slightly ventrally reflexed; with length to breadth ratio of 7–24:1, 15–54 μm long, 2–2.6 μm wide in the widest part (Figs 1–34). No siliceous protrusions on the valve exterior are present (Figs 40–48). Transition of the valve face towards the ventral valve mantle is sharp (Figs 41–48), whereas the transition is gradual on the dorsal side (Figs 41–48). Raphe is long, extending along the mantle for 5–7 μm, barely coming onto the valve face in subapical position (Figs 40–44, 46–48), and not extending past the helictoglossa. Helictoglossa at each apex is massive, expanded into an internal costa which extends obliquely across the valve apex and is penetrated by a single stria (Figs 49–55), with costae clearly visible in the LM (Figs 1–34). One rimoportula per valve is present (Figs 49, 51, 53–55), centered apically on the valve face, with a large external pore easily distinguishable from the external areolae apertures in SEM (Figs 40–41, 43, 46, 47), occasionally visible in LM (e.g., Figs 1, 9, 10, 32). Striae are parallel throughout the valve (Figs 1–34, 40, 43), slightly radiating at the apices (e.g., Figs 41, 42, 48), 21–22 in 10 μm. Areolae are circular, and externally occluded (Figs 40–46), 45–55 in 10 μm.

  • Author
    J.Veselá and J.R.Johans. 2014
  • Length Range
    15–54 µm
  • Width
    2.0–2.6 µm
  • Striae in 10µm

Original Images

Eunotia novaeangliae orig illus
Eun Novae  Original  Descr

Cite This Page

Veselá, J. (2017). Eunotia novaeangliae. In Diatoms of North America. Retrieved April 14, 2024, from https://diatoms.org/species/eunotia_novaeangliae


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