• Category
  • Length Range
    13-24.5 µm
  • Width Range
    5.4-6.1 µm
  • Striae in 10 µm
    24-26 at mid-valve, 28 at the ends
  • Reported As
    Navicula ruttneri var. capitata (ANSP Image Database (NADED ID 93177))



Valves are linear-lanceolate to elliptic-lanceolate, with broadly rounded rostrate to capitate ends. Valves have a strong subapical constriction, except in the smallest valves. The axial area is lanceolate, spanning approximately 1/4 of the valve at its broadest. The central area is bow tie-shaped and incomplete, with marginal striae alternating in length. Striae are radiate throughout, with a slight bend or curve halfway to the valve margin. Stria density increases from 24-26 in 10 µm at the center of the valve to 28 in 10 µm near the apices. Raphe is nearly linear and lateral, with slightly inflated proximal ends and oppositely deflected distal ends. At the termination of the valve there is a small internal notch or depression, visible in LM. Distinctly visible hyaline areas are present at the valve ends. Areolae are not visible in LM.

This species has heretofore not been recorded in North America. However, this is likely due to misidentification as the very similar Sellaphora javanica (replacement name for Navicula ruttneri var. capitata Hustedt). This taxon has been commonly reported in the southeastern United States (Bishop et al. 2017).

It should be noted that the type localities for Sellaphora japonica and Navicula ruttneri var. capitata are Japan and Indonesia, respectively.


The type locality of Sellaphora japonica is Ishimi-gawa, a tributary of Ahiri-gawa, which is itself a tributary of Ara-kawa, where Kobayasi first discovered it. Beyond this drainage, Mayama and Kobayasi (1986) note that this taxon has been found in mosses from Nakatsu Gorge, Arima Valley, and Nippara-gawa as well. The imaged populations for this taxon page derive from samples collected in the southeastern United States. This contributor could not find any records of S. japonica in North America; this is possibly due to misidentification as Navicula ruttneri var. capitata.

Original Description

Stauroneis japonica H. Kobayasi sp. nov. l.c. 69, Fig. 27a-c (nom. nud.)
Valvis 15-25 µ longis, 5 µ latis, inflationibus apudo medianam et terminales magis distinctis, area axiali angusta, zona ampla hyalina cincta, stauro amplissimo, versus marginibus valvae semper dilatato, striis radiantibus, centralibus 24 in 10 µ, terminalibus 28 in 10 µ, sbtiliter punctatis.

  • Basionym
    Stauroneis japonica
  • Author
    H.Kobayasi ex H.Kobayasi and Mayama 1986
  • Length Range
    15-25 µm
  • Width
    5-6 µm
  • Striae in 10µm
    24 near the center, 28 near the ends

Original Images

Sellaphora Japonica Orig Desc 1986 Text
Sellaphora Japonica Orig Desc 1986 Plate
Sellaphora Japonica Orig Desc 1965 Text

Cite This Page

Bishop, I. (2015). Sellaphora japonica. In Diatoms of North America. Retrieved May 28, 2024, from https://diatoms.org/species/sellaphora_japonica


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