• Category
  • Length Range
    21.3-40.1 µm
  • Width Range
    6.8-9.6 µm
  • Striae in 10 µm
    18-22 at the valve center, 22-26 at the ends
  • Reported As
    Muelleria ambigua (Kociolek 2014, p. 40, pl. 54, figs 6-12)

Identification

Description

Valves are elliptic-lanceolate to linear in the largest specimens. The central margin is typically gibbous although some specimens lack a central inflation. Apices are broadly rounded. The raphe is straight and situated between two longitudinal canals. The axial area is narrow and linear, widening slightly near the small, elliptic central area. Proximal raphe ends are unilaterally deflected. Internally, a rectelevatum is present between the two raphe branches, typical for the genus Muelleria. Striae are radiate throughout, the central striae more widely spaced than in the rest of the valve. Areolae in the central striae appear larger and more distinct than areolae in more distal striae. Copulae are evident in girdle view in some specimens. External SEM images show simple round areolae openings, unilaterally bent proximal raphe ends that do not enter the first row of areolae, and bifurcating distal raphe fissures that separate at a wide angle due to the position of a large siliceous flap.

Autecology

Muelleria gibbula has been reported from a wide range of soft water, shallow water, soil and aerophilic habitats (Spaulding et al. 1999). Specimens of Muelleria gibbula pictured on this web page were collected from a small alpine tarn in Grand Teton National Park, Wyoming and a mossy pool high in the Mission Mountains of Montana (photos below).

Sample513101 Lakeat9801Feet
Credit: Beverly Boynton, Adventurers and Scientists for Conservation
Alpine tarn at 9801 feet elevation in the northern Teton Range, Teton County, Wyoming: home of Muelleria gibbula.
Sample513101 Samplesite
Credit: Beverly Boynton, Adventurers and Scientists for Conservation
Sample site where Muelleria gibbula was collected in the alpine tarn pictured above.
Missions Sample4 508001
Credit: Bill Agnew, Adventurers and Scientists for Conservation
Mossy pool in the Mission Mountains, Missoula County, Montana: home of Muelleria gibbula.

Original Description

  • Basionym
    Navicula gibbula
  • Author
    Cleve 1894
  • Length Range
    33-43 µm
  • Width
    8.5-10 µm
  • Striae in 10µm
    16 (middle), 21 (ends)

Original Images

Navicula Gibbula Origimag
Navicula Gibbula Origdesc

Cite This Page

Bahls, L. (2016). Muelleria gibbula. In Diatoms of North America. Retrieved July 23, 2018, from https://diatoms.org/species/muelleria_gibbula

Responses

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