Diatoms of North AmericaDiatoms of North America

Gomphonema mehleri

Camburn 1978

Gomphonema Mehleri Guide
  • Category
    Asymmetric Biraphid
  • Length Range
    33-59 µm
  • Width Range
    9.4-12.5 µm
  • Striae in 10 µm
    7.5-9 at center; 11-12 at headpole; 12-13 at footpole

Identification

Gomp Mehleri 15551B 03232016 Uncounted Gomp1 03 Cl Gomp Mehleri 15592A 08202015 26 Cl Gomp Mehleri 15551A 12162015 03 Cl Gomp Mehleri 15551B 03232016 Uncounted Gomp1 02 Cl 53754A 20161206 01 Typespecimen Cl Gomp Mehleri 15551B2 03242016 08 Cl Gomp Mehleri 15551B2 03242016 07 Cl
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Description

Valves are lanceolate to lanceolate-clavate and broadest near the center of the valve. From the center, the valve evenly tapers to a rounded headpole and variably expanded footpole. The axial area is nearly parallel, becoming tapered at the apices. Striae are coarsely punctate. Striae are weakly radiate at the center valve, becoming nearly parallel at the headpole and strongly radiate at the footpole. In line with the median striae on one side is a single, isolated stigma. Areolae are coarse and rectangular, numbering 16-20 in 10 µm. The raphe is lateral. An apical porefield present at footpole.

This taxon is relatively rare in the southeast region of the US (see Autecology section). It may be that similar species of Gomphonema have been misidentified as G. mehleri. The type image and description are included below from Camburn et al. (1978). Note that specimens illustrated in Kociolek and Kingston (1999) have a higher stria density that the type. Specimens illustrated in Thomas et al. (2009) are smaller, more narrow and have a higher stria density than the type. These differences are larger than expected within our morphological species concept and imply a greater diversity of species in the genus Gomphonema in the southeast than has been recognized.

Autecology

Gomphonema mehleri was described from South Carolina (Long Branch Creek; ANS GC53754). Specimens illustrated here were collected from rivers in Georgia (Little Haynes Creek) and North Carolina (Briar Creek). Note that complete location data is given for each image, by selecting and clicking on the image.

Original Description

Gomphonema mehleri Camburn sp. nov. PL. XV, Figs. 235-236

Valva lanceolata, latissima in medio, attenuata ad apicem et basem rotundatum, apice parum latiore. Area axiali et centrali aream latam lanceolatum formanti. Raphe filmentosa. Strii medianis in unico latere areae centralis puncto singulo terminantibus. Striis distincte punctatis, circa 15 punctis in 10 µm, pro maxima parte radiatis ad fere parallelas ad apicem. Striis 8-9 in 10 µm in medio valvae ad 11 in 10 µm prope apices. Longitudo 52-60 µm. Latitudo 11-11.5 µm.

Holotypus: A.N.S.P. - G.C. #53754, in collectione generali diatomarum Academiae Scientarum Naturalium Philadelphiae.

Valves lanceolate, broadest in the middle, narrowed toward the rounded apex and basis, apex slightly broader. Axial and central area forming a broad, lanceolate area. Raphe filamentous. Median stria on one side of the central area ending in an isolated punctum. Striae distinctly punctate, ca. 15 puncta in 10 µm, radiate throughout most of the valve to almost parallel at the apex. Striae, 8=9 in 10 µm at the center of the valve to 11 in 10 µm near the apices; Length, 52-60 µm; Breadth, 11-11.5 µm.

Holotype: A.N.S.P. - G.C. # 53754, In general diatom collection, Academy of Natural Sciences of Philadelphia.

  • Author
    Camburn 1978
  • Length Range
    52-60 µm
  • Width
    11-11.5 µm
  • Striae in 10µm
    8-9 at center valve, up to 11 near the apices

Original Images

Gomp Mehleri Orig Desc Plate
Gomp Mehleri Orig Desc Text

Cite This Page

Bishop, I. (2016). Gomphonema mehleri. In Diatoms of North America. Retrieved October 30, 2024, from https://diatoms.org/species/gomphonema_mehleri

Responses

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