• Category
  • Length Range
    28.8-66.2 µm
  • Width Range
    11.7-15.0 µm
  • Striae in 10 µm
    14-17 at valve center, 18-21 at the apices

Identification

Description

Valves are broadly lanceolate to elliptic-lanceolate in smaller specimens. Valve margins are convex and apices are cuneate. The raphe branches are straight, located between two longitudinal canals. Proximal raphe ends are unilaterally deflected within a small, elliptic central area. Striae are straight and radiate throughout. The central striae are 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. Under SEM, external areolae openings are lineolate and appear as apically-oriented slits. Proximal raphe ends do not enter the first row of areolae and distal raphe fissures are bifurcate with branches that separate at a wide angle.

More work is needed to determine if this taxon is conspecific with Muelleria spauldinga Kociolek 2014. The observed differences in external areolae openings (lineolate in M. spauldingiae, round in M. spauldinga) may be due to differential erosion of the external foramina. Although the maximum reported size of M. spauldinga is 48 µm long and 12 µm wide, larger valves may yet be found. Internal valve SEM views are needed for both taxa.

Nomenclatural note: The names Muelleria spauldingiana and M. spauldingiae were published for different species in January and March 2014, respectively. The epithet spauldingiana is an adjectival form based on the noun Spaulding. The epithet spauldingiae is the genitive form of the same noun. Although the use of the genitive and the adjectival form of the same word to designate two different species of the same genus should be avoided, the names are not likely to be confused and are not considered to be homonyms according to the Melbourne Code (McNeill et al. 2012, Article 53.3, Example 12).

Autecology

Muelleria spauldingiae has been collected from a small alpine tarn in the Teton Mountains of Wyoming and from a mossy pool in the Mission Mountains of Montana (photos below). These habitats lie at 9801 feet and 7940 feet elevation, respectively.

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

Valves are elliptic to linear-elliptic in the largest specimens. Valve margins are convex and apices are obtusely rounded. Valve length 28.8-66.2 μm; valve width 11.7-15.0 μm. The raphe is straight and filiform between two thickened longitudinal ribs, which occupy a narrow axial area. Proximal raphe ends are bent to the same side within a small elliptic central area. Striae are straight and radiate throughout. Areolae in the central striae appear larger and more distinct than areolae in more distal striae. Striae number 14-17 in 10 μm at valve center, 18-21 in 10 μm at the apices.

  • Author
    Bahls 2014
  • Length Range
    28.8-66.2 µm
  • Width
    11.7-15.0 µm
  • Striae in 10µm
    14-17 at valve center, 18-21 near the apices

Original Images

Figures 127 142

Cite This Page

Bahls, L. (2015). Muelleria spauldingiae. In Diatoms of North America. Retrieved July 23, 2018, from https://diatoms.org/species/muelleria_spauldinga

Responses

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