• Category
  • Length Range
    16.0-42.2 µm
  • Width Range
    6-10 µm
  • Striae in 10 µm
    13-15 on both valves

Identification

Description

Smaller valves are lanceolate, becoming distinctly triundulate in larger specimens, with narrowly rounded to cuneate ends. The raphe valve has a narrow axial area and a rectangular central area reaching the valve margins. The raphe is sinuous externally, with proximal ends deflected slightly in one direction and distal ends curved strongly towards mantle in opposite direction. Internal raphe slits with proximal ends straight. The rapheless valve axial area is near the valve margin. Striae are punctate and radiate throughout on raphe valve. Striae on the rapheless valve are parallel in the center, becoming radiate and curved at the ends of the valves. Internal thickenings separating striae have oblique ridges in in the rapheless valve forming a spiral pattern visible by SEM.

Autecology

This species has been verified from one location, the Iao Valley of Maui, Hawai'i, where it was found on a relatively dry, volcanic rock wall. Other taxa at the site include Cosmioneis sp., Achanthes tumescens, Luticola sp., Diadesmis contenta, Diadesmis sp., and Denticula cf. subtilis.

Original Description

Valves distinctly triundulate in large specimens (Figs 31-34, 41-45), becoming less triundulate and more lanceolate in smaller valves (Figs 35-40, 46-50), with narrowly rounded to cuneate ends, 11-46 µm long, 6-10 µm wide. Raphe valve with narrow axial area and a rectangular central area reaching the valve margins. Raphe externally sinuous, with proximal ends deflected slightly in one direction (Fig. 51), with distal ends curved strongly towards mantle in opposite direction. Internal raphe slits with proximal ends straight (Fig. 52). Rapheless valve with axial area near valve margin. Striae punctate, radiate throughout on raphe valve (Figs 31-40), on rapheless valve parallel in the center becoming radiate with respect to the axial area, curved at ends (Figs 41-50), 13-15 in 10 µm on both valves. Puncta 16 in 10 µm on both valves. Internal costae separating striae with oblique ridges in rapheless valve forming a spiral pattern visible by SEM (Figs 53, 54).

  • Author
    R.L.Lowe and A.R.Sherwood 2009
  • Length Range
    11-46 µm
  • Width
    6-10 µm
  • Striae in 10µm
    13-15 on both valves

Original Images

Achnanthes felinophilia orig illus
Achnanthes felinophila orig desc

Cite This Page

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

Responses

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