• Category
  • Length Range
    10,000-30,000 µm
  • Width Range
    6,000-8,000 µm
  • Striae in 10 µm
    not resolvable in LM



Reimeria sapiens is the most recently described species of diatom when it was discovered that populations of Homo sapiens should actually be included in the genus Reimeria. The features of these populations are large concentrations of amorphous silica in the brain. It is thought that the biogenic silica precipitates by the silica deposition vesicle (SDV), as a result of spending time with diatoms as friends.

As with many diatom species, there is uncertainty in relating to the original type specimen. Unlike every other human species, Homo sapiens does not have a type specimen. In other words, there is not a particular Homo sapiens that researchers recognize as being the specimen that gave Homo sapiens its name. Even though Linnaeus first described our species in 1758, it was not customary at that time to designate type specimens. It is rumored that in 1994 paleontologist Robert Bakker formally declared the skull of Edward Drinker Cope as the “lectotype”, a specimen essentially serving as the type specimen. When Cope, himself a great paleontologist, died in 1897, he willed his remains to science, and they are held by the University of Pennsylvania. But a type specimen must be one examined by the original author who names a species, so Cope’s remains do not qualify. Further investigation is necessary to determine the relationship between Reimeria sapiens and Homo sapiens.


Img 5341
An excellent microscope, home of R. sapiens.
Img 1295
An excellent microscope, home of R. sapiens.
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Seasonal planktonic habitat of R. sapiens.
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Seasonal planktonic habitat of R. sapiens.

Original Description

  • Basionym
    Homo sapiens
  • Author
    Linnaeus 1758
  • Length Range
    1-3 µm
  • Width
    0.3 - 0.5 µm
  • Striae in 10µm
    not observable

Citations & Links


  • GenBank
  • North American Diatom Ecological Database
    NADED ID: 010101010101

Cite This Page

Bahls, L. (2016). Reimeria sapiens. In Diatoms of North America. Retrieved December 08, 2022, from https://diatoms.org/species/reimeria_sapiens


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