Diatoms of North AmericaDiatoms of North America

Meridion anceps

(Ehrenb.) D.M.Williams 1985

Meridion Anceps Guide
  • Category
    Araphid
  • Length Range
    10.4-65 µm
  • Width Range
    5.2-7.0 µm
  • Striae in 10 µm
    18-23
  • Synonyms
    Diatoma anceps (Ehrenb.) Kirchn. 1878

Identification

Meridion anceps LM9 Meridion anceps LM8 Meridion anceps LM6 Meridion anceps LM3 Meridion anceps LM2 Meridion anceps LM5 Meridion anceps LM1
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Description

Valves are apically and transapically symmetric; linear with capitate ends. Small valves, however, may be more elliptical with less capitate ends than larger valves. Valves possess both primary and secondary costae, which measure 3.3-4.9 in 10 µm. Striae are visible in LM but individual areolae cannot be observed. The sternum is central and well-defined. Each valve has a single, sub-apical rimoportula.

Autecology

Meridion anceps is widely distributed across North America, notably in the western United States. It can be found in aerophilic zones, wet walls, small creeks, larger rivers. It is common in submerged mosses and liverworts and co-occurs with several species in the Meridion, Diatoma, Tabellaria, and Tetracylus genera.

Screen Shot 2015 05 08 At 4 13 38 Pm
Credit: USGS BioData
Distribution of D anceps in the continental U.S. rivers sampled for the National Water Quality Assessment program. (Retrieved 08 May 2015)
Screen Shot 2015 05 08 At 4 14 18 Pm
Credit: USGS BioData
Distribution of D anceps in the Alaskan rivers sampled for the National Water Quality Assessment program. (Retrieved 08 May 2015)

Original Description

F? anceps, parva linearis testulis a latere laxe striatis, apicibus, constrictis obtusis subcapitatis. Gomphonema Pupulae affinis.

  • Basionym
    Fragilaria anceps
  • Author
    Ehrenb. 1843

Original Images

Original Description

Updates

Jun 27, 2023 - Expansion of size range

From May 2015 until June 2023, the length range of this taxon was posted as 10.4-45.8 µm. Images of larger specimens were added to the page, and the posted length was updated to 10.4-65 µm. - S. Spaulding

Cite This Page

Bishop, I. (2015). Meridion anceps. In Diatoms of North America. Retrieved April 25, 2024, from https://diatoms.org/species/meridion_ancep

Responses

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