• Category
  • Length Range
    22.6-47.8 µm
  • Width Range
    8-10.5 µm
  • Striae in 10 µm
    13-15 on raphe valve, 12-14 on rapheless valve

Identification

Description

Valves are lanceolate with slightly swollen center and rounded ends. The raphe valve has a narrow axial area with the central area expanded laterally to the valve margins. The proximal raphe ends are deflected slightly in the same direction while the distal raphe ends curve strongly toward the mantle in a direction opposite the proximal raphe ends. The axial area on the rapheless valve is near the valve margin and central area is lacking. On the raphe valve striae are punctate and parallel in the center becoming radiate near the ends. Striae on the rapheless valve are strongly curved near the apicies.

Autecology

Achnanthes longboardia was described from a wet wall in Oahu, Hawaii.

Original Description

Valves lanceolate with rounded ends, slightly swollen near the center in larger valves 19-50.5 long 8-10.5 wide. Raphe valve with narrow axial area with a wide central area expanded laterally to the valve margins. Raphe with proximal ends deflected slightly in the same direction with distal raphe ends curved strongly toward mantle in opposite direction. Rapheless valve with axial area near the valve margin. Striae punctate and parallel in the center becoming radiate near the ends. Striae on the rapheless valve are strongly curved near the apicies.

  • Author
    A.R.Sherwood and R.L.Lowe 2009
  • Length Range
    19-51 µm
  • Width
    8-11 µm

Original Images

Achnanthes longboardia orig illus
Achnanthes longboardia orig descr

Cite This Page

Lowe, R. (2011). Achnanthes longboardia. In Diatoms of North America. Retrieved July 21, 2018, from https://diatoms.org/species/achnanthes_longboardia

Responses

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