Valves are linear-lanceolate, with slightly protracted, rounded apices. The axial area is narrow and linear. The central area is transapically rectangular to bow-tie-shaped. A stigma is located mid-way between the valve center and the margin. Striae are coarsely punctate, with 4-5 areolae per stria. Striae are moderately radiate near the valve center, to strongly radiate near the apices.
Luticola arctica was described from Franz Josef Land, a Russian archipelago. The images shown on this page are from an Alaskan river; this taxon is known only from the Arctic.
12. Luticola arctica Levkov & Metzeltin sp. nov. (Figs 7: 1-25)
Valves linear to linear-lanceolate with convex valve margins. Valve apices protracted, rounded to truncate. Valve length 13.5-40.5 µm, valve width 6.0-8.5 µm. Axial area narrow, linear, slightly wider at central area. Central area wide, asymmetrical, rectangular to bow-tie-shaped stauros, bordered on each margin by a single row of areolae. Single, isolated, stigma in central area, located almost halfway between the valve center and margin. Proximal raphe endings deflected to side opposite stigma. Distal raphe fissures hook-shaped, extending onto valve mantle. Transapical striae with 4-5 round to slightly elongated areolae. Areolae close to valve margin larger. Transapical striae coarse, punctate, moderately radiate near mid-valve, becoming strongly radiate near apices, 12-15 in 10 µm.
Potapova, M. (2019). Luticola arctica. In Diatoms of North America. Retrieved October 15, 2024, from https://diatoms.org/species/luticola-arctica
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Luticola arctica 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.