• Category
  • Length Range
    16-23 µm
  • Width Range
    5.8-6.4 µm
  • Striae in 10 µm
  • Synonyms
    Cymbella sinuata var. antiqua (Grunow) Cleve 1894
    Cymbella sinuata f. antiqua (Grunow) Reimer 1975



Valves are asymmetrical to the apical axis. Both the dorsal and ventral margin are convex. The ventral margin is markedly tumid at the middle of the valve. The apices are protracted to capitate and broadly rounded. The axial area is straight and expanded laterally toward the ventral margin, forming a distinct asymmetrical central area.

The raphe is filiform to weakly lateral and straight. The external proximal raphe ends are slightly dilated. The external distal raphe ends are deflected to the ventral side. A single, round stigma is present in the center of the valve. Striae are parallel to slightly radiate. Striae are composed of areolae that are usually not resolvable in LM. Apical pore fields are distinct and positioned on the ventral margin of the valve.

Further work may show that Reimeria capitata (Cleve-Euler) Levkov and Ector may be the correct name for fo. antiqua, at least with respect to the interpretation by Cleve-Euler (1955, fig. 1203f, g; as compared to Grunow’s taxon as interpreted by Cleve-Euler (1955, fig. 1203c).


This taxon has been reported infrequently across North America, including from Montana (Bahls 2010), the Central and Western Plains (Frey et al. 2011), and Arkansas (Smith 2000). The images displayed here are of specimens from Douglas Lake, Michigan.

Original Description

C. abnormis var. antiqua Grun. Unterscheidet sich von C. abnormis durch die mehr kopfformig verdickten Enden und etwas entfernter stehenden Streifen, welche sehr zart punktirt sind. Bei den meisten recenten Formen der im Umriss sehr variablen C. abnormis ist der mittlere glatte Theil der Bauchseite durch zwei seichte Einschnürungen vom übrigen Theile der Schale gesondert, was bei der fossilen Form (übrigens auch bei manchen jetzt lebenden) nicht der Fall ist. Länge 0.032-0.033 mm, Breite 0.008 mm, Querstreifen 7-8 in 0.01 mm. Hin und wieder. Tab XXIX (I), Fig. 31.

  • Basionym
    Cymbella abnormis var. antiqua
  • Author
    Grunow 1882
  • Length Range
    32-33 µm
  • Width
    8 µm
  • Striae in 10µm

Original Images

Reimeriasinuatafantiqua Origfig
Reimeriasinuatafantiqua Origdesc

Citations & Links

Cite This Page

Kociolek, P., Bishop, I. (2015). Reimeria sinuata f. antiqua. In Diatoms of North America. Retrieved September 25, 2021, from https://diatoms.org/species/reimeria_sinuata_f._antiqua


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Reimeria sinuata f. antiqua 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.